Co-reporter:Zhaojie Wang;Zhenyu Li;Jinghui Sun;Hongnan Zhang;Wei Wang;Wei Zheng
The Journal of Physical Chemistry C April 8, 2010 Volume 114(Issue 13) pp:6100-6105
Publication Date(Web):2017-2-22
DOI:10.1021/jp9100202
Here we demonstrate the preparation and improved hydrogen monitoring properties based on p-NiO/n-SnO2 heterojunction composite nanofibers via the electrospinning technique and calcination procedure. NiO/SnO2 heterojuction composite nanofibers were spin-coated on the ceramic tube with a pair of Au electrodes for the detection of hydrogen. Extremely fast response−recovery behavior (∼3s) has been obtained at the operable temperature of 320 °C, based on our gas sensor, with the detection limit of approximate 5 ppm H2. The role of the addition of NiO into the SnO2 nanofibers and the sensing mechanism has also been discussed in this work.
Co-reporter:Rui Zhao, Xiang Li, Bolun Sun, He Ji, Ce Wang
Journal of Colloid and Interface Science 2017 Volume 487() pp:297-309
Publication Date(Web):1 February 2017
DOI:10.1016/j.jcis.2016.10.057
An environmentally benign and efficient hydrothermal carbonization method is widely applied for the preparation of carbon-based adsorbents. However, the adsorption capacity toward anionic species would be influenced due to the negatively charged surface of the traditional hydrothermal carbonaceous materials; moreover most of the carbonaceous materials were in the form of powder which restricted the practical applications. Herein, amino-rich hydrothermal carbon-coated electrospun polyacrylonitrile fiber (PAN@NC) adsorbents were obtained through one-step hydrothermal carbonization approach assisted by diethylenetriamine using polyacrylonitrile (PAN) fibers as the templates, which showed highly efficient adsorption for anionic pollutants. The PAN@NC fibers were characterized in detail to confirm their structures and composition. The flexible and robust PAN@NC fiber membrane exhibited high adsorption capacity and good regeneration and recycling ability toward the anionic metal ion Cr(VI) and herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). According to the Langmuir model, the adsorption behaviors showed monolayer adsorption capacities of 290.70 mg/g and 164.47 mg/g for Cr(VI) and 2,4-D, respectively, which were higher than that of many other adsorbents. Recycling study indicated that the removal efficiencies for both pollutants retained above 90% after five cycles. These findings demonstrate that PAN@NC fibers are promising adsorbents for the removal of anionic pollutants from wastewater solutions.
Co-reporter:Guangdi Nie;Xiaofeng Lu;Wei Wang;Maoqiang Chi;Yanzhou Jiang
Materials Chemistry Frontiers 2017 vol. 1(Issue 5) pp:859-866
Publication Date(Web):2017/05/04
DOI:10.1039/C6QM00232C
A simple and green strategy was proposed for the first time to fabricate uniform polyaniline (PANi) thorn/BiOCl chip (BPB) heterostructures at a low temperature without the assistance of any surfactant. During the synthetic process, Bi2S3 nanowires acted as both the sacrificial template and the Bi source for BiOCl, affording the synchronous formation of HCl-doped PANi conductive arrays and BiOCl chips supported on residual Bi2S3 nanowires. As expected, when utilized as electrode materials for supercapacitors, the obtained BPB nanocomposite exhibited a better electrochemical performance in neutral media with enhanced specific capacitance, a more acceptable rate capability and a smaller charge-transfer resistance in comparison with the individual PANi nanofibers due to the unique hierarchical nanostructure of BPB and the synergistic effect between the ionizable BiOCl and the PANi chain.
Co-reporter:Rui Zhao;Xiang Li;Bolun Sun;Yanzi Li;Yumei Li;Rui Yang
Journal of Materials Chemistry A 2017 vol. 5(Issue 3) pp:1133-1144
Publication Date(Web):2017/01/17
DOI:10.1039/C6TA09784G
Cr(VI) is a well-known highly toxic metal ion and a thorough cleanup of this pollutant in wastewater is of special concern. Herein, a novel branched polyethylenimine (bPEI) grafted electrospun polyacrylonitrile (PAN) fiber membrane for Cr(VI) remediation based on adsorption was synthesized by a facile refluxing approach. Benefiting from the electrospinning process, the diameter of PAN fibers could be decreased to hundreds of nanometers from more than ten micrometers, which led to a higher adsorption capacity toward Cr(VI). In addition, the electrospun fibers showed good membrane forming properties, guaranteeing their application in the filtration purification process. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), elemental analysis, contact angle and so forth were used to characterize the grafted fiber membranes. Different grafting ratios were achieved by varying the refluxing time to search for the optimized removal capacity toward Cr(VI). The adsorption properties of the grafted fiber membrane including batch adsorption and filtration adsorption were investigated. The results revealed that the bPEI grafted electrospun PAN fiber adsorbent possessed an excellent adsorption capacity toward Cr(VI) (qm = 637.46 mg g−1), which was higher than many other adsorbents. Moreover, the batch adsorption and dynamic filtration could also make the Cr(VI) concentration notably decrease from 10 or 5 mg L−1 to below 0.05 mg L−1, which is recommended as the drinking water standard by WHO. The obtained results suggested that the grafted electrospun fiber membrane could be potentially applied to the efficient removal of Cr(VI) in wastewater treatment.
Co-reporter:Mu Gao;Xiaofeng Lu;Maoqiang Chi;Sihui Chen
Inorganic Chemistry Frontiers 2017 vol. 4(Issue 11) pp:1862-1869
Publication Date(Web):2017/11/07
DOI:10.1039/C7QI00458C
Mixed transition-metal oxides (MTMOs) have attracted much research interest because of their promising applications in artificial enzymes. In this work, uniform hollow MnCo2O4 nanofibers have been fabricated via an electrospinning technique followed by a calcination process, which can be used as efficient oxidase mimics. In detail, the as-prepared hollow MnCo2O4 nanofibers display excellent oxidase-like activity toward the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) superior to their corresponding single-metal oxides without the addition of H2O2. Based on the high catalytic activity of hollow MnCo2O4 nanofibers and their inhibition effect by specific substances, the system of hollow MnCo2O4 nanofibers–TMB has potential to be applied in assays to detect sulfite and L-cysteine using a colorimetric approach with high sensitivity and selectivity. This work implies a broad application prospect of MTMOs in biosensors, environmental protection, food safety and medical science.
Co-reporter:Yumei Li, Xiang Li, Rui Zhao, Chuying Wang, Fangping Qiu, Bolun Sun, He Ji, Ju Qiu, Ce Wang
Materials Science and Engineering: C 2017 Volume 72() pp:106-112
Publication Date(Web):1 March 2017
DOI:10.1016/j.msec.2016.11.052
•Electrospun PCL fibers were subjected to an O2 plasma treatment to improve the hydrophilicity.•PANI was coated onto the surface of PCL fibers successfully after the plasma treatment.•HUVECs could attach, spread, and survive better on PANI-PCL fibers than on pure PCL fibers.•Electrical stimulation benefited proliferation of HUVECs on conductive PANI-PCL scaffold.Recently, electrically conductive biomaterial scaffolds have shown great potential in tissue regeneration. Herein, we reported an electrically conductive polyaniline (PANI) coated poly(ε-caprolactone) (PCL) electrospun micron-fiber scaffold for the enhanced attachment and proliferation of human umbilical vein endothelial cells (HUVECs) under electrical stimulation conditions. After the O2 plasma treatment toward PCL electrospun fiber, PANI could be polymerized onto their surfaces successfully. The obtained PANI-PCL fibers were characterized by SEM observations, FT-IR spectra, XPS analysis, and water contact angle measurement. The mechanical tests indicated that the fibers could satisfy the practical vascular scaffold requirements. The conductivity of the PANI-PCL fibers was 6.71 × 10− 3 S/cm which could provide a conductive in-vitro platform to study the effect of electrical stimulation on HUVECs proliferation. When PANI-coated PCL fibers were compared with PCL fibers, HUVECs exhibited highly enhanced adhesion and viability, especially under electrical stimulation (ES) of 200, 300, and 400 mV/cm. Proliferation of HUVECs on PANI-PCL fibers was strongly dependent on electrical stimulation intensity. The results showed new insights into conductive scaffolds for vascular tissue engineering.
Co-reporter:Rui Zhao, Yong Wang, Xiang Li, Bolun Sun, Yumei Li, He Ji, Ju Qiu, and Ce Wang
ACS Sustainable Chemistry & Engineering 2016 Volume 4(Issue 5) pp:2584
Publication Date(Web):April 6, 2016
DOI:10.1021/acssuschemeng.6b00026
Recently, much attention has been focused on the hydrothermal carbonization processes that use biomass as a carbon source to produce functional carbonaceous materials. Despite much progress in their synthesis and applications, flexible and high mechanical strength hydrothermal carbonaceous materials are in demand in practical environmental applications. In this work, a flexible hydrothermal carbon-coated electrospun PAN fiber membrane was developed. The carbon-coated PAN fibers showed an enhanced mechanical strength and were found to possess a good adsorption capacity toward paraquat. After the NaOH activation, the adsorption process became more efficient. The hydrothermal carbon coating and activation reactions were confirmed by SEM observations, TEM images, FT-IR spectra, Raman spectra, XPS analysis, and mechanical tests. The adsorption process followed the Langmuir isotherm and pseudo-second-order kinetic model; meanwhile, the activated adsorbent (AC-PAN) had a good recyclability and the removal efficiency remained at 83% after five cycles. The maximum adsorption capacity for AC-PAN was 437.64 mg/g, which was higher than those in classic paraquat adsorbents. Given the high adsorption and regenerability performance of the activated hydrothermal carbon-coated electrospun PAN fibers, they should have potential applications in water remediation.Keywords: Adsorption; Electrospinning; Flexibility; Hydrothermal carbonization; Paraquat;
Co-reporter:Ziqiao Jiang, Rui Zhao, Bolun Sun, Guangdi Nie, He Ji, Junyu Lei, Ce Wang
Ceramics International 2016 Volume 42(Issue 14) pp:15881-15888
Publication Date(Web):1 November 2016
DOI:10.1016/j.ceramint.2016.07.060
Abstract
In this study, a series of undoped and Eu-doped SnO2 nanofibers were synthesized via a simple electrospinning technique and subsequent calcination treatment. Field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were carefully used to characterize the morphologies, structures and chemical compositions of these samples. The results reveal that the as-prepared nanofibers are composed of crystallite grains with an average size of about 10 nm and Eu3+ ions are successfully doped into the SnO2 lattice. Compared with pure SnO2 nanofibers, Eu-doped SnO2 nanofibers demonstrate significantly enhanced sensing characteristics (e.g., large response value, short response/recovery time and outstanding selectivity) toward acetone vapor, especially, the optimal sensor based on 2 mol% Eu-doped SnO2 nanofibers shows the highest response (32.2 for 100 ppm), which is two times higher than that of the pure SnO2 sensor at an operating temperature of 280 °C. In addition, the sensor exhibits a good sensitivity to acetone in sub-ppm concentrations and the detection limit could extend down to 0.3 ppm, making it a potential candidate for the breath diagnosis of diabetes.
Co-reporter:Guangdi Nie, Xiaofeng Lu, Maoqiang Chi, Yanzhou Jiang and Ce Wang
RSC Advances 2016 vol. 6(Issue 60) pp:54693-54701
Publication Date(Web):18 May 2016
DOI:10.1039/C6RA08607A
A novel composite nanostructure of C–CoOx–C with CoOx nanoparticles embedded in N-containing porous graphite carbon nanofibers (CNF) is successfully prepared via sintering the electrospun polyacrylonitrile–cobalt acetate tetrahydrate nanofibers covered by a polypyrrole (PPy) sheath that were attained from the chemical vapor-phase polymerization of pyrrole monomers using concentrated nitric acid as both the dopant and oxidant for the first time. The unique configuration with a well-defined morphology possesses a large specific surface area and prominent conductivity contributed to by the catalysis of metallic Co and the external PPy-derived carbon envelope, which could facilitate effective electron transfer and rapid ion penetration in C–CoOx–C, thus improving its electrochemical performance. As expected, when employed as an electrode active material for supercapacitors, the resultant C–CoOx–C showed a more acceptable specific capacitance, better rate capability and higher cycling stability than individual CNF and CoOx nanoparticle-decorated CNF without the coating of a N-doped carbon layer from PPy (C–CoOx).
Co-reporter:Rui Zhao, Yong Wang, Xiang Li, Bolun Sun, and Ce Wang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 48) pp:26649
Publication Date(Web):November 16, 2015
DOI:10.1021/acsami.5b08403
Water-insoluble β-cyclodextrin-based fibers were synthesized by electrospinining followed by thermal cross-linking. The fibers were characterized by field-emission scanning electron microscopic (FE-SEM) and Fourier transformed infrared spectrometer (FT-IR). The highly insoluble fraction obtained from different pH values (3–11) indicates successful cross-linking reactions and their usability in aqueous solution. After the cross-linking reaction, the fibers’ tensile strength increases significantly and the BET surface area is 19.49 m2/g. The cross-linked fibers exhibited high adsorption capacity for cationic dye methylene blue (MB) with good recyclability. The adsorption performance can be fitted well with pseudo-second-order model and Langmuir isotherm model. The maximum adsorption capacity is 826.45 mg/g according to Langmuir fitting. Due to electrostatic repulsion, the fibers show weak adsorption toward negatively charged anionic dye methyl orange (MO). On the basis of the selective adsorption, the fiber membrane can separate the MB/MO mixture solution by dynamic filtration at a high flow rate of 150 mL/min. The fibers can maintain good fibrous morphology and high separation efficiency even after five filtration–regeneration cycles. The obtained results suggested potential applications of β-cyclodextrin-based electrospun fibers in the dye wastewater treatment field.Keywords: adsorption; dye; electrospinning; separation; β-cyclodextrin
Co-reporter:Guangdi Nie, Xiaofeng Lu, Junyu Lei, Liu Yang, Ce Wang
Electrochimica Acta 2015 Volume 154() pp:24-30
Publication Date(Web):1 February 2015
DOI:10.1016/j.electacta.2014.12.090
•Bi2S3 nanorods-reduced graphene oxide nanosheet (BGNS) composites were prepared.•A simple and facile one-pot hydrothermal reaction was developed.•The synthetic procedure could accomplish the controlled fabrication of BGNS hybrids.•The novel BGNS composites exhibited enhanced supercapacitor performance.Bi2S3 nanorods-reduced graphene oxide nanosheet (BGNS) composites with uniform morphology have been successfully prepared via a facile one-pot hydrothermal reaction using thioacetamide (TAA) as both the sulfur source and reducing agent. The simple and versatile synthetic procedure could accomplish the controlled fabrication of BGNS hybrids with tunable size and composition through adjusting the additive amount of GO. When employed as active materials for supercapacitor electrodes, in comparison with pristine rGO and X-Bi2S3 that obtained in the absence of GO, the BGNS composites displayed enhanced electrochemical performance by combining desired functions of individual components and introducing extra synergistic effects into the system. It is believed that the novel BGNS composites with multifarious advantages including nontoxicity, abundant resource and low cost are promising for practical application in supercapacitors.
Co-reporter:Ziqiao Jiang, Tingting Jiang, Jinfeng Wang, Zhaojie Wang, Xiuru Xu, Zongxin Wang, Rui Zhao, Zhenyu Li, Ce Wang
Journal of Colloid and Interface Science 2015 Volume 437() pp:252-258
Publication Date(Web):1 January 2015
DOI:10.1016/j.jcis.2014.09.056
•Sr-doped SnO2 nanofibers have been successfully obtained via electrospinning and calcination.•Sr-doped SnO2 nanofibers show high response and rapid response/recovery behavior to ethanol.•Sr-doped SnO2 nanofibers exhibit good discriminative ability to ethanol from acetone.•Sr-doped SnO2 nanofibers display good selectivity to some reducing gases.We demonstrated a new metal oxides based chemiresistor (MOC), which exhibits fast response/recovery behavior, large sensitivity, and good selectivity to ethanol, enabled by Sr-doped SnO2 nanofibers via simple electrospinning and followed by calcination. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS) were carefully used to characterize their morphology, structure, and composition. The ethanol sensing performances based on Sr-doped SnO2 nanofibers were investigated. Comparing with the pristine SnO2 nanofibers, enhanced ethanol sensing performances (more rapid response/recovery behavior and larger response values) have been achieved owing to the basic SnO2 surface caused by Sr-doping, whereas the acetone sensing performances have been weakened. Thus, good discriminative ability to ethanol from acetone has been realized. Additionally, Sr-doped SnO2 nanofibers also exhibit good selectivity.
Co-reporter:Zhaojie Wang, Siyuan Liu, Tingting Jiang, Xiuru Xu, Jun Zhang, Changhua An and Ce Wang
RSC Advances 2015 vol. 5(Issue 79) pp:64582-64587
Publication Date(Web):23 Jul 2015
DOI:10.1039/C5RA08863A
Highly-efficient chemical sensors based on various nanostructures have attracted considerable attention owing to their practical applications in industry and in the daily lives of human beings. One of the most interesting and urgent challenges is to synthesize hierarchical heterostructured nanomaterials with high performance. In this paper, hierarchical p–n junction nanostructures made of n-type SnO2 nanosheets standing on p-type carbon nanofibers have been successfully fabricated by combining electrospinning technique and hydrothermal method. The morphologies of the SnO2 nanosheets can be easily controlled through tuning the experimental conditions such as hydrothermal reaction time. The gas sensing performances based on the hierarchical nanostructures with hydrogen as target molecule have been evaluated. The expected sensing performances (e.g., low operating temperature, large response and fast response-recovery behaviors) have been achieved owing to the synergistic effect between SnO2 nanosheets, CNFs and the well-defined shaped hybrid nanostructures.
Co-reporter:Mengqi Shen, Lianbo Ma, Jun Zhu, Xiang Li and Ce Wang
RSC Advances 2015 vol. 5(Issue 73) pp:59659-59664
Publication Date(Web):25 Jun 2015
DOI:10.1039/C5RA10476A
An assembled-nanosheets discus-like Ni(OH)2 hierarchical structure is synthesized through a facile solvothermal method without any surfactant used in the synthesis. The morphology and microstructure of the Ni(OH)2 products can be tuned using the solvothermal temperature. The as-prepared Ni(OH)2 samples are investigated as electrode materials for supercapacitors. It is found that the assembled-nanosheets Ni(OH)2 hierarchical structure exhibits excellent capacitive performance with a specific capacitance as high as 1830.3 F g−1 at a current density of 1.0 A g−1, great electrochemical stability with a capacitance retention of 98.9% after 1000 cycles at a constant current density of 10 A g−1, and a high energy density of 146.4 W h kg−1. The remarkable capacitive performance can be attributed to the unique hierarchical structure of the Ni(OH)2 product, which can facilitate the penetration and migration of electrolyte ions, shorten the diffusion distance of charges and increase the utilization of active materials. The excellent capacitive performance makes the Ni(OH)2 hierarchical architecture a promising electrode material for electrochemical energy storage applications.
Co-reporter:Rui Zhao, Xiang Li, Bolun Sun, Yan Tong, Ziqiao Jiang and Ce Wang
RSC Advances 2015 vol. 5(Issue 22) pp:16940-16949
Publication Date(Web):02 Feb 2015
DOI:10.1039/C4RA16208K
The ideal wound dressing should achieve rapid healing with hemostasis, antimicrobial activity, maintenance of a moist wound bed, etc. The electrospun blend mat meets the requirements outlined for wound healing, by their microfibrous structures providing a suitable environment for wound healing. In this study, a dual-layer nanofiber blend mat wound dressing of nitrofurazone (NFZ)-loaded poly(L-lactide) (PLLA)/sericin nanofibers and NFZ-loaded PLLA nanofibers is fabricated by electrospinning. The NFZ-loaded PLLA/sericin nanofibers act as the first layer and then the NFZ-loaded PLLA nanofibers are the second layer to prepare the dual-layer fiber dressings. The prepared dual-layer NFZ-loaded fiber dressings have satisfactory antibacterial activity against both Gram-positive and Gram-negative bacteria. In vitro drug release studies show that the drug release profiles can be controlled by adjusting the drug amount in different layers of the dual-layer dressings. The methyl thiazolyl tetrazolium (MTT) assays demonstrate that the NFZ-loaded PLLA/sericin fibers are nontoxic and biocompatible. In vivo wound healing tests are performed in rats. The results reveal that the dual-layer fiber dressings perform better than commercial non-woven dressing in decreasing wound size. It is observed at 12 days that the wound size reduction is 97% for being dressed with the dual-layer fiber dressings but 84% for the commercial woven dressing. These NFZ-loaded PLLA/sericin‖PLLA dual-layer fiber mats may provide a promising candidate for accelerating wound healing.
Co-reporter:Weining Sun, Xiaofeng Lu, Yan Tong, Junyu Lei, Guangdi Nie and Ce Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 19) pp:6740-6746
Publication Date(Web):20 Feb 2014
DOI:10.1039/C3TA15441F
In this report, a palladium/polypyrrole/polyacrylonitrile (Pd/PPy/PAN) composite nanofiber membranes was synthesized by a one-pot redox polymerization process between pyrrole monomers and Na2PdCl4 in the presence of electrospun PAN nanofibers, without the introduction of any other surfactants or reductants. The as-prepared Pd/PPy/PAN nanofiber membrane exhibited good catalytic performance towards hydrogen generation from the hydrolysis of ammonia borane (AB). The apparent activation energy (Ea) was calculated to be about 33.5 kJ mol−1. In addition, the Pd nanoparticles (Pd NPs) were encapsulated in PPy layers on the surface of the PAN nanofibers, enabling the catalyst to be stable against poisoning and easily separated from the suspension system. The catalytic activity does not weaken after five cycles. This study indicated that the obtained Pd/PPy/PAN composite nanofiber membrane could be applied as an alternative in exploring new catalysts for hydrogen generation, as hydrogen is an important fuel as a clean power source.
Co-reporter:Guangdi Nie, Xiaofeng Lu, Junyu Lei, Ziqiao Jiang and Ce Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 37) pp:15495-15501
Publication Date(Web):19 Jun 2014
DOI:10.1039/C4TA01732C
V2O5-doped α-Fe2O3 composite nanotubes have been successfully fabricated via a simple one-step electrospinning technique followed by calcination treatment. For the first time, we found that the magnetic properties of the as-prepared samples were significantly dependent on the contents of the dopant. In comparison with pristine α-Fe2O3, perfect reversibility, more excellent capacitance and better cycling stability were simultaneously observed for the hybrid metal oxide with an appropriate mass ratio of V2O5 (VFNT1) when it was utilized for supercapacitor electrodes, indicating that the doped α-Fe2O3 tubular nanostructures are fairly promising for practical applications not only in magnetic recording but also in the energy storage field.
Co-reporter:Yan Tong, Xiaofeng Lu, Weining Sun, Guangdi Nie, Liu Yang, Ce Wang
Journal of Power Sources 2014 Volume 261() pp:221-226
Publication Date(Web):1 September 2014
DOI:10.1016/j.jpowsour.2014.03.051
•The electrospun nanofibers were firstly used for the hydrogen generation.•Ag/Pd NPs were uniformly distributed on the surface of the PAN nanofibers.•The PAN/Ag/Pd composite nanofibers exhibited excellent catalytic activity.•Good recycle stability and easy separation from the reacted system was achieved.A high-performance hydrogen generation system based on the electrospun polyacrylonitrile (PAN)/Ag/Pd composite nanofibers, which were prepared by microwave reducing the electrospun PAN/AgNO3 nanofibers and followed by a replacement reaction has been demonstrated. The morphology of the as-prepared PAN/Ag/Pd composite nanofibers and the metal nanoparticles on the fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements. It has been demonstrated that the obtained PAN/Ag/Pd composite nanofibers possess fine morphology and high catalytic activities for H2 generation from aqueous solution of ammonia borane (NH3BH3, AB). The H2 generation test exhibited that the catalyst had excellent catalytic activity (with turnover frequency (TOF) of 377.2 mol H2 h−1 (mol Pd)−1), good recycle stability and easy-separation from the reaction system. This new kind of nanofibers possesses great potential application for the new clean energy development.
Co-reporter:Ye Li, Yuan Liang, Xitao Wang, Min Xie, Xincai Liu, Ce Wang
International Journal of Hydrogen Energy 2014 Volume 39(Issue 13) pp:7060-7068
Publication Date(Web):24 April 2014
DOI:10.1016/j.ijhydene.2014.02.116
•Branched sulfonated poly(ether ether ketone)s containing intermolecular ionic cross-linkable groups were synthesized.•Benzoxazole groups were grafted onto the polymer backbone via thiol-ene click reaction.•The membranes exhibited low swelling, low methanol permeability and improved chemical stability.A series of novel branched sulfonated poly(ether ether ketone)s containing intermolecular ionic cross-linkable groups, benzoxazole groups, have been prepared for direct methanol fuel cells. The benzoxazole groups are grafted onto the polymer chain via a thiol-ene click chemistry reaction. The expected structures of the copolymers are confirmed by 1H NMR and Fourier transform infrared spectroscopy. Compared with the unmodified polymer membrane, the ionic cross-linked membranes show enhanced thermal and mechanical properties. We also investigate the changes in water uptake, proton conductivity and chemical stability. The dense membrane structures formed by branching and the interactions between sulfonic acid and benzoxazole groups make a great contribution to the improvements of dimensional stability and methanol resistance property. Although the proton conductivities of the ionic cross-linked membranes are lower than the pristine membrane, the selectivities are much higher. The results show that the novel copolymers in this study are possible potential candidate materials for proton electrolyte membrane.
Co-reporter:Weining Sun, Xiaofeng Lu, Yan Tong, Zhen Zhang, Junyu Lei, Guangdi Nie, Ce Wang
International Journal of Hydrogen Energy 2014 Volume 39(Issue 17) pp:9080-9086
Publication Date(Web):5 June 2014
DOI:10.1016/j.ijhydene.2014.03.197
•GO nanosheets decorated with ultrafine Pd nanoparticles have been fabricated.•The Pd/GO nanocomposites show remarkable catalytic activity and good stability.•The catalytic activity is much higher than the conventional Pd/C catalysts.In this report, graphene oxide (GO) nanosheets decorated with ultrafine Pd nanoparticles (Pd NPs) have been successfully fabricated through a reaction between [Pd2(μ-CO)2Cl4]2− and water in the presence of GO nanosheets without any surfactant or other reductant. The as-synthesized small Pd NPs with average diameter of about 4.4 nm were well-dispersed on the surface of GO nanosheets. The Pd/GO nanocomposites show remarkable catalytic activity toward the hydrogenation of p-nitrophenol at room temperature. The kinetic apparent rate constant (kapp) could reach about 34.3 × 10−3 s−1. Furthermore, the as-prepared Pd/GO nanocomposites could also be used as an efficient and stable catalyst for hydrogen production from hydrolytic dehydrogenation of ammonia borane (AB). The catalytic activity is much higher than the conventional Pd/C catalysts.
Co-reporter:Weining Sun;Xiaofeng Lu;Yanpeng Xue;Yan Tong
Macromolecular Materials and Engineering 2014 Volume 299( Issue 3) pp:361-367
Publication Date(Web):
DOI:10.1002/mame.201300171
In this report, CoFe2O4/Polypyrrole (PPy)/Pd ternary composite nanofibers are fabricated through a one-step redox reaction between pyrrole and Na2PdCl4 in the presence of electrospun CoFe2O4 nanofibers in ethylene glycol (EG). The generation of Pd nanoparticles is accompanied by the formation of PPy on the surface of electrospun CoFe2O4 nanofibers during the redox reaction. The as-prepared CoFe2O4/PPy/Pd composite nanofibers may be used as efficient catalysts for the p-nitrophenol hydrogenation with an apparent rate constant (kapp) of about 13.2 × 10−3 s−1. The CoFe2O4/PPy/Pd composite nanofibers show good magnetic properties, which can be readily recycled under an external magnetic field.
Co-reporter:Xiang Li, Rui Zhao, Bolun Sun, Xiaofeng Lu, Chengcheng Zhang, Zhaojie Wang and Ce Wang
RSC Advances 2014 vol. 4(Issue 80) pp:42376-42382
Publication Date(Web):03 Sep 2014
DOI:10.1039/C4RA03692A
α-Fe2O3–γ-Al2O3 core–shell nanofibers have been synthesized via an electrospinning process combined with vapor deposition and heat treatment techniques. The composite nanofibers exhibited ferromagnetic properties and Cr(VI) removal performance. The Freundlich adsorption isotherm was applied to describe the adsorption process. Kinetics of the Cr(VI) ion adsorption were found to follow a pseudo-second-order rate equation. The obtained α-Fe2O3–γ-Al2O3 core–shell nanofibers were carefully examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM). The adsorption mechanism for Cr(VI) onto α-Fe2O3–γ-Al2O3 core–shell nanofibers was elucidated by X-ray photoelectron spectroscopy (XPS). The results suggested that the electrostatic adsorption between the positively charged surface of α-Fe2O3–γ-Al2O3 nanofibers and Cr(VI) species, and the electron–hole pair provided by Fe2O3 induced the Cr(VI) reduction to Cr(III). It is anticipated that the α-Fe2O3–γ-Al2O3 core–shell nanofibers are an attractive adsorbent for the removal of heavy metal ions from water.
Co-reporter:Zhaojie Wang, Zhenyu Li, Xiuru Xu, Tingting Jiang, Hongnan Zhang, Wei Wang and Ce Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 2) pp:213-215
Publication Date(Web):17 Sep 2012
DOI:10.1039/C2TC00101B
One-dimensional (1D) semiconducting nanostructures, as both interconnections and functional units in fabricating electronic, biological/chemical sensors, optoelectronic, electrochemical, and electromechanical devices, attract immense interest. However, all those 1D semiconducting nanostructures are sensitive to both volatile organic compounds (VOFs) and relative humidity (RH), causing the instability of those devices operated in air (except in biological/chemical sensors). Herein, we demonstrated an effective route to not only stabilize 1D semiconducting nanostructures in air but also maintain their electrical properties by constructing 1D isomeric semiconducting nanorods on 1D semiconducting nanostructures to form 1D isomeric and hierarchical semiconducting nanostructures. 1D isomeric and hierarchical TiO2 nanostructures (IHTNs) were chosen as a model, both excellent air stability and good electrical properties can be achieved. With such IHTNs as building blocks, a stable field-effect transistor has been realized.
Co-reporter:Tingting Jiang, Zhaojie Wang, Zhenyu Li, Wei Wang, Xiuru Xu, Xincai Liu, Jinfeng Wang and Ce Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 17) pp:3017-3025
Publication Date(Web):08 Mar 2013
DOI:10.1039/C3TC00370A
This paper describes the exploration of a synergic effect within n-type inorganic–p-type organic nano-hybrids in gas sensors. One-dimensional (1D) n-type SnO2–p-type PPy composite nanofibers were prepared by combining the electrospinning and polymerization techniques, and taken as models to explore the synergic effect during the sensing measurement. Outstanding sensing performances, such as large responses and low detection limits (20 ppb for ammonia) were obtained. A plausible mechanism for the synergic effect was established by introducing p–n junction theory to the systems. Moreover, interfacial metal (Ag) nanoparticles were introduced into the n-type SnO2–p-type PPy nano-hybrids to further supplement and verify our theory. The generality of this mechanism was further verified using TiO2–PPy and TiO2–Au–PPy nano-hybrids. We believe that our results can construct a powerful platform to better understand the relationship between the microstructures and their gas sensing performances.
Co-reporter:Zhaojie Wang, Zhenyu Li, Tingting Jiang, Xiuru Xu, and Ce Wang
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 6) pp:2013
Publication Date(Web):February 27, 2013
DOI:10.1021/am3028553
Pd0-loaded SnO2 nanofibers have been successfully synthesized with different loaded levels via electrospinning process, sintering technology, and in situ reduction. This simple strategy could be expected to extend for the fabrication of similar metal–oxide loaded nanofibers using different precursors. The morphological and structural characteristics of the resultant product were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS). To demonstrate the usage of such Pd0-loaded SnO2 nanomaterial, a chemical gas sensor has been fabricated and investigated for H2 detection. The sensing performances versus Pd0-loaded levels have been investigated in detail. An ultralow limit of detection (20 ppb), high response, fast response and recovery, and selectivity have been obtained on the basis of the sensors operating at room temperature. The combination of SnO2 crystal structure and catalytic activity of Pd0-loaded gives a very attractive sensing behavior for applications as real-time monitoring gas sensors.Keywords: catalytic activity; crystal structure; hydrogen sensors; Pd0-loaded; room temperature; SnO2 nanofibers;
Co-reporter:Shutao Wang;Erik B. Berda;Xiaofeng Lu;Xiaofeng Li;Danming Chao
Macromolecular Rapid Communications 2013 Volume 34( Issue 20) pp:1648-1653
Publication Date(Web):
DOI:10.1002/marc.201300448
Co-reporter:Guangdi Nie, Xiaofeng Lu, Junyu Lei, Liu Yang, Xiujie Bian, Yan Tong, Ce Wang
Electrochimica Acta 2013 Volume 99() pp:145-151
Publication Date(Web):1 June 2013
DOI:10.1016/j.electacta.2013.03.066
Pure Pd hollow nanocubes assembled with uniform nanoparticles were successfully fabricated via a one-step redox reaction by using Cu2O nanocubes as both sacrificial templates and the reducing agents. Almost no residual Cu2O cores remained in the final Pd cubic nanoshells which were composed of nanograins with an average diameter of approximately 6.5 nm. A wide liner range (0.1–24.0 mM), a relatively high sensitivity (287.7 mA M−1 cm−2) and a comparable detection limit (7.4 μM, S/N = 3) were observed in the electrochemical experiments, indicating that the obtained Pd hollow nanocubes as enzyme-free catalysts possessed excellent electrocatalytic activity to the reduction of H2O2.
Co-reporter:Yan Tong, Zhicheng Li, Xiaofeng Lu, Liu Yang, Weining Sun, Guangdi Nie, Zhaojie Wang, Ce Wang
Electrochimica Acta 2013 Volume 95() pp:12-17
Publication Date(Web):15 April 2013
DOI:10.1016/j.electacta.2013.02.004
An electrochemical method for the detection of dopamine based on a glass carbon electrode modified with electrospun CeO2/Au composite nanofibers was investigated in this article. The CeO2/Au composite nanofibers were prepared by the electrospinning technique and then annealed in air. The CeO2/Au composite nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements. Cyclic voltammetry (CV) showed that the electrospun CeO2/Au composite nanofibers modified carbon glass electrode exhibited an excellent electrocatalytic response to the dopamine (DA). The detection limit (S/N = 3) was as low as 0.056 μM and the sensitivity could reach 127 μA mM−1 cm−2. All these demonstrated that the electrospun CeO2/Au composite nanofibers were good electrocatalyst for the oxidation of dopamine.
Co-reporter:Rui Yang, Danming Chao, Hongtao Liu, Erik B. Berda, Shutao Wang, Xiaoteng Jia, Ce Wang
Electrochimica Acta 2013 Volume 93() pp:107-113
Publication Date(Web):30 March 2013
DOI:10.1016/j.electacta.2013.01.109
A novel water-soluble self-doped oligoaniline derivative (WSOAD) was synthesized by oxidative coupling method. The prepared WSOAD showed expected spectroscopic properties, and also revealed good solubility in strong polar solvents and aqueous media across a pH range of 1–14. WSOAD displayed excellent electroactivity in acid, neutral and even in alkaline solutions (pH = 10) due to self-doping effect between oligoaniline and sulfonic acid groups. Moreover, the inhibition effect of WSOAD on the cold rolled steel in 1.0 M HCl solution was studied by weight loss and potentiodynamic polarization measurements. The results showed that WSOAD was a good inhibitor in HCl medium.Graphical abstractWe report the synthesis of a novel water-soluble self-doped oligoaniline derivative (WSOAD). Due to the self-doping effect, WSOAD exhibits excellent electroactivity in acid and neutral solutions. WSOAD displays good inhibition performance for the corrosion of cold rolled steel in HCl medium.Highlights► A novel water-soluble self-doped oligoaniline derivative (WSOAD) was synthesized. ► The WSOAD exhibits excellent electrochemical activity in acid and neutral solutions. ► The WSOAD was a good candidate for inhibiting the corrosion of cold rolled steel.
Co-reporter:Shutao Wang, Danming Chao, Erik B. Berda, Xiaoteng Jia, Rui Yang, Ce Wang
Electrochimica Acta 2013 Volume 89() pp:594-599
Publication Date(Web):1 February 2013
DOI:10.1016/j.electacta.2012.10.149
A novel electroactive poly(amic acid) (EDA-CON-EPAA) containing oligoaniline pendants, azobenzene and sulfonic acid groups was synthesized by copolymerization. The synergistic interplay of these three distinct functional groups results in a number of interesting and novel properties. The polymer showed photoisomerization induce by irradiation with ultraviolet light and visible light by virtue of azobenzene groups, and also revealed excellent electroactivity in acid, neutral and even in alkaline solutions (pH = 12) due to self-doping between oligoaniline and sulfonic acid (and/or carboxylic acid) groups. Moreover, EDA-CON-EPAA displayed acceptable electrochromic performance even in alkaline solutions and multiple colors attributed to the complementary effects of the two chromophores, which greatly enlarged the range of the electrochromic application. The coloration efficiency could still reach 93.8 cm2/C (at 700 nm) even at pH = 10.
Co-reporter:Guangdi Nie, Liang Zhang, Xiaofeng Lu, Xiujie Bian, Weining Sun and Ce Wang
Dalton Transactions 2013 vol. 42(Issue 38) pp:14006-14013
Publication Date(Web):15 Jul 2013
DOI:10.1039/C3DT51489G
CuS-graphene nanosheet (GNS) composites with well-defined morphology have been successfully fabricated via a simple one-pot hydrothermal route by using thioacetamide (TAA) as both the sulfur source and reducing agent. The as-prepared CuS-GNS composites with an appropriate content of graphene exhibited an even higher peroxidase-like catalytic activity than pristine CuS nanoparticles in acetate buffer solution (pH = 4.0), which provided a facile method for the colorimetric detection of hydrogen peroxide (H2O2). It was calculated that H2O2 could be detected as low as 1.2 μM (S/N = 3) with a wide linear range from 2.0 to 20.0 μM (R2 = 0.992), indicating that the as-prepared catalyst as an artificial peroxidase is promising for application in biosensors and environmental monitoring.
Co-reporter:Ye Li, Xitao Wang, Min Xie, Xincai Liu, Ce Wang
International Journal of Hydrogen Energy 2013 Volume 38(Issue 36) pp:16276-16285
Publication Date(Web):13 December 2013
DOI:10.1016/j.ijhydene.2013.10.036
•A series of BSPEEK containing propenyl groups were synthesized.•Benzimidazole sulfonic acid groups have been grafted onto the polymer backbone via thiol-ene click reaction.•The membranes exhibited enhanced proton conductivity, relative lower water uptake and methanol permeability.A series of novel branched sulfonated poly(ether ether ketone)s containing propenyl groups have been synthesized using a nucleophilic polycondensation reaction. Subsequently, a thiol-ene click chemistry reaction between propenyl and thiol groups results in a new series of copolymers containing benzimidazole sulfonic acid groups. The expected structures of the copolymers are confirmed by 1H NMR and Fourier transform infrared spectroscopy. The introduction of benzimidazole sulfonic acid groups into the copolymer improves proton conductivity obviously. Compared with the linear sulfonated poly(ether ether ketone)s with the same sulfonation degree (DS), the BSPEEK-BIS membranes show lower water uptake and methanol permeability. The branching structure and the interaction between sulfonic acid and benzimidazole groups make the contribution to the improvement of the membrane's properties. Therefore, the high proton conduction, low methanol permeation, and low water uptake property of the as-prepared membranes are of significant interest for DMFCs.
Co-reporter:Ye Li, Min Xie, Xitao Wang, Danming Chao, Xincai Liu, Ce Wang
International Journal of Hydrogen Energy 2013 Volume 38(Issue 27) pp:12051-12059
Publication Date(Web):10 September 2013
DOI:10.1016/j.ijhydene.2013.06.090
•Br-SPEEK were obtained via two-step polymerization.•The polymer exhibited higher degree of branching values.•The membrane showed improved mechanical strength, excellent dimensional stability.In this article, novel branched sulfonated poly(ether ether ketone)s (Br-SPEEK) containing various amounts of 1,3,5-tris(4-fluorobenzoyl)benzene as the branching agent have been successfully prepared. Compared with the traditional linear polymer membranes, the membranes prepared by Br-SPEEK showed improved mechanical strength, excellent dimensional stability and superior oxidative stability with similar proton conductivity. Notably, the Br-SPEEK-10 membrane began to break after 267 min in Fenton's reagent at 80 °C, which was 4 times longer than that of the L-SPEEK. Although the proton conductivity decreased with the addition of the branching agent, satisfying methanol permeability value was observed (down to 6.3 × 10−7 cm2 s−1), which was much lower than Nafion 117 (15.5 × 10−7 cm2 s−1). All the results indicated that the novel branched sulfonated poly(ether ether ketone)s membrane was potential candidate as proton conductive membranes for application in fuel cells.
Co-reporter:Guangdi Nie, Zhicheng Li, Xiaofeng Lu, Junyu Lei, Chengcheng Zhang, Ce Wang
Applied Surface Science 2013 Volume 284() pp:595-600
Publication Date(Web):1 November 2013
DOI:10.1016/j.apsusc.2013.07.139
Highlights
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CuS NPs were immobilized on the surface of the electrospun PAN nanofibers.
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CuS NPs were monodispersed and uniformly distributed.
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The fabricated PAN/CuS composite nanofibers exhibited excellent catalytic activity.
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The PAN/CuS composite nanofibers as Fenton-like reagents showed good reusability.
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The PAN/CuS composite nanofibers could be applied in dye wastewater treatment.
Co-reporter:Shutao Wang, Danming Chao, Erik B. Berda, Xiaoteng Jia, Rui Yang, Xitao Wang, TingTing Jiang and Ce Wang
RSC Advances 2013 vol. 3(Issue 12) pp:4059-4065
Publication Date(Web):17 Jan 2013
DOI:10.1039/C3RA00056G
A novel, well-defined, multifunctional electroactive poly(amic acid) (EPAA) containing oligoaniline pendants was synthesized by a one-step synthetic route. The structure was confirmed spectroscopically via nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectra, and the thermal stability was probed via thermogravimetric analysis (TGA). The oligoaniline pendants imparted excellent electroactivity, photoresponsiveness to chemical redox and electrochemical modulation, and expectable electrochromic performance to the obtained EPAA. Leucoemeraldine base EPAA (LEPAA), emeraldine base EPAA (EEPAA) and HCl-doped emeraldine base EPAA (HCl-doped EEPAA) nanofibers were fabricated by electrospinning and were characterized by scanning electron microscopy (SEM) to test their morphology, and a contact angle goniometer was used to test their hydrophilicity. The as-prepared HCl-doped EEPAA nanofibers were then evaluated for their ability to sense ammonia.
Co-reporter:Dinhthao Vu, Xiang Li, Zhenyu Li, and Ce Wang
Journal of Chemical & Engineering Data 2013 Volume 58(Issue 1) pp:71-77
Publication Date(Web):December 11, 2012
DOI:10.1021/je301017q
TiO2 nanofibers (NFs) with different phases such as amorphous, anatase, mixed anatase–rutile, and rutile have been prepared by combining the electrospinning technique with the subsequent process of heat treatment or acidic-dissolution method. The obtained NFs are characterized by a Fourier transform infrared spectrometer (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2 adsorption–desorption isotherm measurements. Phase structure effects of electrospun TiO2 NFs on As(III) adsorption behaviors have been investigated. The results showed a significant effect of the phase structures of TiO2 NFs on As(III) adsorption rates and capacities. Amorphous TiO2 NFs have the highest As(III) adsorption rate and capacity in the investigated samples, which can be attributed to its higher surface area and porous volume. This research provides a simple and low-cost method for phase-controlled fabrication of TiO2 NFs and application for effective removal of arsenic from aqueous solution.
Co-reporter:Yang Yang;Renzhong Fu;Haiying Wang
Microchimica Acta 2013 Volume 180( Issue 13-14) pp:1249-1255
Publication Date(Web):2013 October
DOI:10.1007/s00604-013-1041-4
We have developed a 3-dimensional (3-D) electrochemical sensor for highly sensitive detection of hydrogen peroxide (H2O2). Porous 3-D carbon nanofibers (CNFs), prepared by electrospinning, served as scaffold on a glassy carbon electrode. The 3-D CNFs were functionalized with platinum nanoparticles (Pt-NPs) by in-situ gas-phase decomposition of platinum salts at high temperature. The Pt-NPs act as an electrocatalyst for the decomposition of H2O2. TEM revealed that large amounts of Pt-NPs are deposited in the electrospun CNFs electrode even without using any stabilizer or reducing reagent. The sensor was investigated by cyclic voltammetry and amperometry and displays a good response to H2O2 with a linear range between 10 μM and 15 mM (R = 0.9994), a low detection limit (3.4 μM at a signal-to-noise ratio of 3), and a response time of 3 s. The sensor shows excellent stability and selectivity.
Co-reporter:Danming Chao;Shutao Wang;Rui Yang;Erik B. Berda
Colloid and Polymer Science 2013 Volume 291( Issue 11) pp:2631-2637
Publication Date(Web):2013 November
DOI:10.1007/s00396-013-3012-z
A novel multifunctional poly(amic acid) bearing oligoaniline, fluorene groups (PAAOF) has been prepared through the one-step synthetic route. The structure of PAAOF was confirmed via nuclear magnetic resonance (NMR), Fourier-transform infrared spectra (FTIR), and gel permeation chromatography (GPC). Moreover, the electrochemical measurement results revealed that PAAOF material have an expected electrochemical activity, and good electrochromic properties with high contrast value and satisfactory coloration efficiency. The photophysical properties of the as-synthesized PAAOF at various oxidation states were studied. The results indicated that the fluorescence of PAAOF could be tuned by modulating the oxidation states of oligoaniline segments. In the fluorescence tuning, the fluorene groups are fluorophore, and the oligoaniline segments are used as regulatory unit.
Co-reporter:Dinhthao Vu;Xiang Li
Science Bulletin 2013 Volume 58( Issue 14) pp:1702-1707
Publication Date(Web):2013 May
DOI:10.1007/s11434-013-5717-2
Poly(acrylo-amidino ethylene amine) (PAEA) nanofiber membranes have been synthesized by combining the electrospinning technique and subsequent chemical modification. The membranes were used to remove As(V) from aqueous solution. The adsorption kinetics, equilibrium isotherms, and pH effect were investigated in batch experiments. The Langmuir isotherm and pseudo second-order kinetic models agree well with the experimental data. The PAEA nanofibers are effective for As(V) adsorption at pH 3. Experimental results showed that the maximum adsorption capacity of the PAEA nanofibers with As(V) is 76.92 mg g−1, which is much higher than that of the PAEA microfibers (27.62 mg g−1). The adsorption rate of PAEA nanofibers is faster than that of PAEA microfibers due to its higher specific surface area. The PAEA nanofibers can be used as an effective adsorbent for the removal of As(V) in aqueous solution due to high adsorption capacity and short adsorption time to achieve equilibrium.
Co-reporter:DinhThao Vu;Xiang Li
Science China Chemistry 2013 Volume 56( Issue 5) pp:678-684
Publication Date(Web):2013 May
DOI:10.1007/s11426-012-4817-1
Porous chitosan(CS)/magnetic(Fe3O4)/ferric hydroxide(Fe(OH)3) microsphere as novel and low-cost adsorbents for the removal of As(III) have been synthesized via the electrospraying technology by a simple process of two steps. Characterization of the obtained adsorbents was studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The adsorption kinetics and equilibrium isotherms were investigated in batch experiments. The Langmuir, Freundlich isotherm and pseudo-second order kinetic models agree well with the experimental data. The adsorption of As(III) onto CS/Fe3O4/Fe(OH)3 microspheres occurred rapidly and reached adsorption equilibrium after about 45 min. The maximum adsorption capacity of CS/Fe3O4/Fe(OH)3 microspheres, calculated by the Langmuir isotherm model, was 8.47 mg g−1, which is higher than that of CS/Fe3O4/Fe(OH)3 prepared by the conventional method (4.72 mg g−1). The results showed that the microspheres had a high adsorption capacity for As(III) and a high separation efficiency due to their microporous structure and superparamagnetic characteristics. Present research may eventually lead to a simple and low cost method for fabricating microporous materials and application for removal of arsenic from aqueous solution.
Co-reporter:Libing He;Shutao Wang;Xincai Liu;Danming Chao
Journal of Polymer Research 2013 Volume 20( Issue 8) pp:
Publication Date(Web):2013 August
DOI:10.1007/s10965-013-0214-5
A novel hyperbranched polyamide containing azobenzene and oligoaniline groups (HPA-AO) has been synthesized by A2+BB’2 strategy. The structures of the obtained HPA-AO were confirmed via nuclear magnetic resonance (NMR) and Fourier-transform infrared spectra (FTIR); morphological data was ascertained via X-ray diffraction (XRD). The HPA-AO exhibited good thermodynamic stability. Due to the introduction of oligoaniline segments, the HPA-AO material was endowed with reversible electroactivity, and adjustable dielectric properties. Furthermore, the optical properties of HPA-AO were studied in detail and the results indicated that this azobenzene-containing polymer possessed expected photoisomerization, photoinduced birefringence and patterning properties.
Co-reporter:Danming Chao, Libing He, Erik B. Berda, Shutao Wang, Xiaoteng Jia, Ce Wang
Polymer 2013 Volume 54(Issue 13) pp:3223-3229
Publication Date(Web):7 June 2013
DOI:10.1016/j.polymer.2013.04.021
A novel multifunctional hyperbranched polyamide bearing oligoaniline, azobenzene and triphenylbenzene (PAOAF) has been prepared through a pyridine/LiCl-mediated acylation reaction. The structure of PAOAF was confirmed via nuclear magnetic resonance (NMR), Fourier-transform infrared spectra (FTIR), X-ray diffraction (XRD) and gel permeation chromatography (GPC). The thermal stability was probed via thermogravimetric analysis (TGA). The electrochemical activity of PAOAF was explored by cyclic voltammetry in 1.0 M H2SO4 confirming a surface controlled process. Tunable dielectric property of PAOAF has been accomplished by controlling the isomerization of azobenzene groups using UV/Vis irradiation. The electrochromic performance of a PAOAF/ITO electrode was studied by spectrochronoamperometry in detail, exhibiting good electrochromic properties with high contrast value and satisfactory coloration efficiency. Moreover, the fluorescence of PAOAF was modulated by controlling the oxidation degree of oligoaniline segments because of the energy migration occurring between oligoaniline and triphenylbenzene groups.
Co-reporter:Xiaofeng Lu, Xiujie Bian, Guangdi Nie, Chengcheng Zhang, Ce Wang and Yen Wei
Journal of Materials Chemistry A 2012 vol. 22(Issue 25) pp:12723-12730
Publication Date(Web):24 May 2012
DOI:10.1039/C2JM16559G
This work describes the encapsulation of conducting polypyrrole (PPy) into electrospun TiO2 nanofibers to form PPy/TiO2 nanocomposites using V2O5 as an oxidant and sacrificial template via a simple vapor phase polymerization approach. The PPy/TiO2 nanocomposites could be used as nanoreactors for loading Pd nanocatalysts towards the catalytic reduction of p-nitrophenol by sodium borohydride (NaBH4) at ambient conditions. The Pd nanocrystals synthesized through the in situ reduction by the PPy/TiO2 matrix have a small size of only about 2.0 nm. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible-near infrared spectroscopy (UV-vis-NIR) and thermo-gravimetric analysis (TGA) results demonstrated that PPy/TiO2 and PPy/TiO2/Pd composite nanofibers were successfully synthesized. Pd nanoparticles supported on the PPy/TiO2 composite nanofibers exhibited good catalytic activity when they worked as catalysts for the reduction of p-nitrophenol. The apparent kinetic rate constant (Kapp) was calculated to be about 12.2 × 10−3 s−1. The protective PPy/TiO2 composite nanofibers render the Pd nanoparticles stable against poisoning by the product of the reaction, enabling the composite nanocatalysts to be recyclable when used over multiple cycles.
Co-reporter:Danming Chao, Xiaoteng Jia, Fuquan Bai, Hongtao Liu, Lili Cui, Erik B. Berda and Ce Wang
Journal of Materials Chemistry A 2012 vol. 22(Issue 7) pp:3028-3034
Publication Date(Web):04 Jan 2012
DOI:10.1039/C1JM13422A
We describe the synthesis of a novel poly(aryl ether), containing pendant oligoaniline and anthracene moieties (PAE-p-OA), and both side chains present in equal amounts. Structures were confirmed spectroscopically via nuclear magnetic resonance (NMR), morphological data ascertained viaX-ray diffraction (XRD), and thermal stability probed viathermogravimetric analysis (TGA). Electrochemical and photophysical properties were also investigated using cyclic voltammetry and UV-Vis and fluorescence spectroscopy. This material exhibits an interesting fluorescent response to redox active species. When PAE-p-OA is in the reduced state, oxidative materials interact with the oligoaniline side chains resulting in a progression from leucoemeraldine base (LEB) to the emeraldine base (EB). The resulting change in molecular conformation of the oliganiline unit increases its propensity for interaction with the anthracene side chain (corroborated by molecular modeling), leading to decreased fluorescence via quenching and thus “turn off” fluorescence sensing. When PAE-p-OA is in the oxidized state, reduction of the oligoaniline from the EB to the LEB via interaction with a reductive species delivers “turn on” fluorescence sensing via decreased interaction between the oligoaniline and anthracene side chains, again due to a change in the molecular conformation of oligoaniline.
Co-reporter:Wei Wang, Zhenyu Li, Tingting Jiang, Zhiwei Zhao, Ye Li, Zhaojie Wang, and Ce Wang
ACS Applied Materials & Interfaces 2012 Volume 4(Issue 11) pp:6080
Publication Date(Web):October 22, 2012
DOI:10.1021/am301712t
Conducting polymers-based gas sensors have attracted increasing research attention these years. The introduction of inorganic sensitizers (noble metals or inorganic semiconductors) within the conducting polymers-based gas sensors has been regarded as the generally effective route for further enhanced sensors. Here we demonstrate a novel route for highly-efficient conducting polymers-based gas sensors by introduction of polymeric sensitizers (polymeric adsorbent) within the conducting polymeric nanostructures to form one-dimensional polymeric adsorbent/conducting polymer core–shell nanocomposites, via electrospinning and solution-phase polymerization. The adsorption effect of the SPEEK toward NH3 can facilitate the mass diffusion of NH3 through the PPy layers, resulting in the enhanced sensing signals. On the basis of the SPEEK/PPy nanofibers, the sensors exhibit large gas responses, even when exposed to very low concentration of NH3 (20 ppb) at room temperature.Keywords: electrospinning; gas sensor; one-dimensional core−shell structure; polymeric sensitizer; polypyrrole; sulfonated poly(ether ether ketone);
Co-reporter:Lirong Kong, Xincai Liu, Xiujie Bian and Ce Wang
RSC Advances 2012 vol. 2(Issue 7) pp:2887-2894
Publication Date(Web):10 Feb 2012
DOI:10.1039/C2RA00657J
In this work, a simple hydrothermal method is presented for fabricating hierarchically porous silica nanocubes using a surfactant-polyelectrolyte template. The formed silica nanocubes possess Pmn symmetry, which are patterned after organic template and their shape can be easily transformed from solid nanocubes to hollow cubes by controlling the composition of the surfactant-polyelectrolyte template. We have studied the fabrication conditions of silica nanocubes as a function of reaction temperature, reaction time, and the amount of reactants, and proposed a nanoparticle formation mechanism. For drug delivery, the calcined solid and hollow silica nanocubes show high loading capacities of ibuprofen, 362 mg g−1 and 509 mg g−1, respectively. These properties make the hierarchically porous silica nanocubes a promising material for drug delivery.
Co-reporter:Junyu Lei, Xiaofeng Lu, Wei Wang, Xiujie Bian, Yanpeng Xue, Ce Wang and Lijuan Li
RSC Advances 2012 vol. 2(Issue 6) pp:2541-2544
Publication Date(Web):07 Feb 2012
DOI:10.1039/C2RA01065H
MnO2/graphene oxide (GO) composite nanosheets have been successfully fabricated by a simple wet-chemical synthetic route. The composition and structure of the resulting MnO2/GO composites were characterized by transmission electron microscopy (TEM), energy dispersive X-ray diffraction (EDX), Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) patterns. The MnO2/GO composite nanosheets exhibited good electrocatalytic behavior in detecting hydrazine at an applied potential of +0.6 V. The sensor showed a good linear dependence on hydrazine concentration in the range of 3 × 10−6 to 1.12 × 10−3 with a sensitivity of 1007 μA mM−1 cm−2. The detection limit is 0.16 μM at the signal-to-noise ratio of 3. Furthermore, the MnO2/GO modified electrode exhibits freedom from interference by other co-existing electroactive species. These results demonstrate that MnO2/GO composites have great potential in the application of hydrazine detection.
Co-reporter:Wei Wang, Xiaofeng Lu, Zhenyu Li, Xiang Li, Xiuru Xu, Junyu Lei, Ce Wang, Ray H. Baughman, Shaoli Fang
Organic Electronics 2012 Volume 13(Issue 11) pp:2319-2325
Publication Date(Web):November 2012
DOI:10.1016/j.orgel.2012.06.033
A novel one-dimensional (1D) polymeric heterojunction based on weak-acceptor-polyacrylonitrile/donor-polyaniline core–shell nanofibers is designed for photoconductive devices through electrospinning followed by solution polymerization. Such 1D heterojunction can not only provide the large phase-separated nano-interface for effective charges separation between the cores and shells, but also facilitate the mass charge collection and transport along the nanofiber structure, resulting in greatly enhanced optoelectronic performance. The short 0.1 s response time upon irradiation is among the fastest values, as is the short 0.1 s time for return to the non-irradiated state. Extremely high on–off resistivity ratios (exceeding 4 × 104) can be obtained under the drive voltage of only 0.01 V, indicating the energy required for electrical input is very small. Higher drive voltages (a modest 10 V) can provide a very high responsivity of 20 A W−1 driven by 365 nm UV irradiation. Moreover, the as-prepared flexible photoconductive device maintains performance even after bending fatigue tests for bending angles as large as 180°.Graphical abstractA novel polymeric heterojunction based on weak-acceptor-polyacrylonitrile/donor-polyaniline core-shell nanofibers is designed for photoconductive application through electrospinning followed by solution polymerization. The heterojunction provides phase-separated nano-interface for charges separation between the cores and shells, and quasi-one-dimensional charge collection and transport along the nanofiber structure, resulting in greatly enhanced optoelectronic performance.Highlights► The first example of all-polymeric 1D core–shell acceptor–donor heterojunction for photoelectronics. ► Phase-separated nano-interface for charges separation between the cores and shells. ► Quasi-one-dimensional charge collection and transport along the nanofibers. ► The as-prepared devices can bear fatigue tests without degradation of device performances. ► Excellent photoconductive performance suggests applications viability.
Co-reporter:Xiaoteng Jia;Danming Chao;Erik B. Berda;Shutao Wang;Rui Yang;Lei Yao;C. Wang
Macromolecular Chemistry and Physics 2012 Volume 213( Issue 14) pp:1475-1481
Publication Date(Web):
DOI:10.1002/macp.201200087
Abstract
A novel poly(aryl ether ketone) bearing pendant aniline tetramers (PAEK-p-AT) is prepared through nucleophilic aromatic polycondensation. Structures are confirmed via nuclear magnetic resonance, Fourier-transform infrared spectra, and X-ray diffraction. The electrochemical activity of PAEK-p-AT is explored by cyclic voltammetry in 1.0 M H2SO4 and confirms a surface controlled process. Moreover, the doped PAEK-p-AT shows a high dielectric constant at room temperature during dielectric testing. The electrochromic performance of a PAEK-p-AT film is investigated by spectrochronoamperometry in detail, exhibiting good electrochromic properties with high contrast value, satisfactory coloration efficiency, and moderate switching times.
Co-reporter:E. Jin;Xiujie Bian;Xiaofeng Lu
Journal of Materials Science 2012 Volume 47( Issue 10) pp:4326-4331
Publication Date(Web):2012 May
DOI:10.1007/s10853-012-6283-8
In this article, Prussian blue (PB) covered multiwalled carbon nanotubes (MWCNTs)/polypyrrole (PPy) ternary composite nanofibers with good dispersibility in water and ethanol have been prepared by directly mixing ferric-(III) chloride and potassium ferricyanide in the presence of MWCNT/PPy coaxial nanofibers under ambient conditions. Transmission electron microscopy shows that the as-synthesized PB nanoparticles covered on the surface of MWCNT/PPy nanofibers. Fourier-transform infrared spectroscopy, UV–Visible spectroscopy, and X-ray diffraction patterns have been used to characterize the obtained MWCNT/PPy/PB ternary composite nanofibers. The MWCNT/PPy/PB ternary composite nanofibers exhibit good electrocatalytic response to detection of H2O2 and provide a new material to modify electrode for amperometric biosensors.
Co-reporter:Xiaofeng Lu;Yanpeng Xue;Guangdi Nie
Catalysis Letters 2012 Volume 142( Issue 5) pp:566-572
Publication Date(Web):2012 May
DOI:10.1007/s10562-012-0802-8
A facile and aqueous-phase method based on the electron transfer reduction process for fabricating core-sheath structured polyaniline (PANI)/SnO2 composite nanorods supported Pd nanocatalyst has been demonstrated. The Pd nanoparticles synthesized by this strategy have a small size of smaller than 3.0 nm. The well dispersed Pd nanoparticles with small sizes supported on core-sheath PANI/SnO2 composite nanorods exhibited an ultrahigh catalytic activity during the catalytic reduction of p-nitrophenol into p-aminophenol by NaBH4 in aqueous solution. The kinetic apparent rate constant (kapp) reach to be about 26.9 × 10−3 s−1. It is believed that this method could be extended to cover many kinds of other functional composite nanomaterials where the active component is expected to bring in new features and applications.
Co-reporter:Tian Zheng, Xiaofeng Lu, Xiujie Bian, Chengcheng Zhang, Yanpeng Xue, Xiaoteng Jia, Ce Wang
Talanta 2012 Volume 90() pp:51-56
Publication Date(Web):15 February 2012
DOI:10.1016/j.talanta.2011.12.066
CNT/PPy/KxMnO2, a novel ternary core–shell nanowires, was successfully prepared by a two-step self-assembly method and utilized as an electrocatalyst for the oxidation of hydrogen peroxide. The as-synthesized products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy and Fourier-transform infrared spectra (FTIR) measurements. The results exhibited that the KxMnO2 nanosheets were grown on the surface of CNT/PPy core–shell nanotubes. The planes of the KxMnO2 nanosheets were more or less perpendicular to the CNT/PPy nanotubes. Cyclic voltammetry (CV) results demonstrated that the CNT/PPy/KxMnO2 composite nanowires, as a nonenzyme catalyst, performed well with regards to the oxidation of hydrogen peroxide in 0.1 M phosphate buffer solution (pH 7.0). The composite had a fast response with a linear range of 5.0 μM to 9.7 mM and a relatively low detection limit of 2.4 μM (S/N = 3). The sensitivity of the sensor for H2O2 was 114.6 μA mM−1 cm−2. These excellent properties might be due to the large surface area of the composite nanowires and the quick electron transfer promoted by the combination of CNT and PPy.Highlights► Novel ternary core–shell CNT/PPy/KxMnO2 nanowires are prepared by a two-step self-assembly method. ► KxMnO2 nanosheets are grown more or less perpendicular to the CNT/PPy nanotubes. ► The CNT/PPy/KxMnO2 nanowires exhibit good performance as electrocatalysts towards the oxidation of H2O2.
Co-reporter:Danming Chao;Rui Yang;Xiaoteng Jia;Hongtao Liu;Shutao Wang;Erik B. Berda
Journal of Polymer Science Part A: Polymer Chemistry 2012 Volume 50( Issue 12) pp:2330-2336
Publication Date(Web):
DOI:10.1002/pola.26010
Abstract
A novel multifunctional poly(aryl ether) with both pendant oligoaniline and fluorene groups (PAE-p-OF) was synthesized by nucleophilic polycondensation and characterized by 1H NMR, Fourier-transform infrared spectra, and gel permeation chromatography. The polymer showed excellent solubility in common organic solvents and good thermal stability. Electrochemical and photophysical properties were also investigated using cyclic voltammetry, UV–vis, and fluorescence spectroscopies. The obtained PAE-p-OF exhibits satisfactory electrochromic properties with high contrast value, acceptable coloration efficiency, and moderate switching times. Moreover, the fluorescence intensity of PAE-p-OF was modulated by controlling oxidation degree of oligoaniline moiety, due to the energy migration occurring between oligoaniline and fluorene groups. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Co-reporter:Xiaofeng Lu, Wanjin Zhang, Ce Wang, Ten-Chin Wen, Yen Wei
Progress in Polymer Science 2011 Volume 36(Issue 5) pp:671-712
Publication Date(Web):May 2011
DOI:10.1016/j.progpolymsci.2010.07.010
Intrinsically conducting polymers have been studied extensively due to their intriguing electronic and redox properties and numerous potential applications in many fields since their discovery in 1970s. To improve and extend their functions, the fabrication of multi-functionalized conducting polymer nanocomposites has attracted a great deal of attention because of the emergence of nanotechnology. This article presents an overview of the synthesis of one-dimensional (1D) conducting polymer nanocomposites and their properties and applications. Nanocomposites consist of conducting polymers and one or more components, which can be carbon nanotubes, metals, oxide nanomaterials, chalcogenides, insulating or conducting polymers, biological materials, metal phthalocyanines and porphyrins, etc. The properties of 1D conducting polymer nanocomposites will be widely discussed. Special attention is paid to the difference in the properties between 1D conducting polymer nanocomposites and bulk conducting polymers. Applications of 1D conducting polymer nanocomposites described include electronic nanodevices, chemical and biological sensors, catalysis and electrocatalysis, energy, microwave absorption and electromagnetic interference (EMI) shielding, electrorheological (ER) fluids, and biomedicine. The advantages of 1D conducting polymer nanocomposites over the parent conducting polymers are highlighted. Combined with the intrinsic properties and synergistic effect of each component, it is anticipated that 1D conducting polymer nanocomposites will play an important role in various fields of nanotechnology.
Co-reporter:Xiaoteng Jia, Danming Chao, Erik B. Berda, Songhao Pei, Hongtao Liu, Tian Zheng and Ce Wang
Journal of Materials Chemistry A 2011 vol. 21(Issue 45) pp:18317-18324
Publication Date(Web):14 Oct 2011
DOI:10.1039/C1JM14047G
A novel, well-defined multifunctional polyamide bearing pendent aniline tetramer groups has been synthesized via low temperature solution polycondensation. The simultaneous presence of these two functional groups allows the polyamide to display the properties of azo-chromophore and oligoaniline, such as photoinduced birefringence and reversible electroactivity. The electrochromic performance of the polyamide shows the optical change in absorptivity depends on the various redox states of oligoaniline upon electrochemical switching. It is well known that a change in absorptivity is accompanied by a concomitant change in refractive index. By taking advantage of this effect and using the single step fabrication of surface relief gratings based on azo-chromophore, we have fabricated optical diffraction gratings with which the diffraction efficiency can be modulated by an electrochemical signal. Although patterned electroactive films have been made by many techniques, the copolymer approach employing the simple one-step surface relief gratings process displays optimal properties with respect to modulation depth and convenience, which avoids complicated electropolymerization steps or photochemical reactions. The electrochemically-induced modulation in the diffraction efficiency of the polyamide is believed to arise primarily from the effect of the redox state on the film's refractive index.
Co-reporter:Libing He, Danming Chao, Xiaoteng Jia, Hongtao Liu, Lei Yao, Xincai Liu and Ce Wang
Journal of Materials Chemistry A 2011 vol. 21(Issue 6) pp:1852-1858
Publication Date(Web):03 Dec 2010
DOI:10.1039/C0JM02960B
By an oxidative coupling polymerization approach, we have synthesized a novel electroactive polymer with good solubility containing alternating phenyl-capped aniline tetramer in the main chain and azo chromophores in the side chain. Dielectric properties of the as-synthesized polymer were investigated in detail and gratifying results have been observed. Firstly, a large enhancement in the dielectric constant was achieved utilizing the method of doping the conjugated oligoaniline segments with hydrochloric acid. Secondly, the adjustment of dielectric constant was implemented primarily by means of exposing the samples to UV and visible irradiation, mainly owing to the photoisomerization derived from azo chromophores in the side chain. The detailed characteristics of the as-synthesized polymer were systematically studied by Fourier-transform infrared (FTIR) spectra, nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). UV-vis spectra were used to monitor the photoisomerization and doping process of the polymer. The thermal characteristics of the polyamide were evaluated by thermogravimetric analysis (TGA). Moreover, the electrochemical activity of the polymer was explored by cyclic voltammogram (CV) measurement, showing that the intrinsic electroactivity of the oligoaniline was maintained in the polymer.
Co-reporter:Lirong Kong, Xiaofeng Lu, Xiujie Bian, Wanjin Zhang, and Ce Wang
ACS Applied Materials & Interfaces 2011 Volume 3(Issue 1) pp:35
Publication Date(Web):December 14, 2010
DOI:10.1021/am101077a
Fe3O4 microsphere is a good candidate as support for catalyst because of its unique magnetic property and large surface area. Coating Fe3O4 microspheres with other materials can protect them from being dissolved in acid solution or add functional groups on their surface to adsorb catalyst. In this paper, a carbon layer was coated onto Fe3O4 microspheres by hydrothermal treatment using polyethylene glycol as the connecting agents between glucose and Fe3O4 spheres. Through tuning the added amounts of reactants, the thickness of the carbon layer could be well-controlled. Because of the abundant reductive groups on the surface of carbon layer, noble metal ions could be easily adsorbed and in situ reduced to nanoparticles (6−12 nm). The prepared catalyst not only had unique antiacid and magnetic properties, but also exhibited a higher catalytic activity toward the reduction of methyl orange than commercially used Pd/C catalyst.Keywords: coating; environmental degradation; functional composites; magnetic properties; nanocomposites
Co-reporter:Xiaoteng Jia, Danming Chao, Hongtao Liu, Libing He, Tian Zheng, Xiujie Bian and Ce Wang
Polymer Chemistry 2011 vol. 2(Issue 6) pp:1300-1306
Publication Date(Web):12 Apr 2011
DOI:10.1039/C1PY00035G
A series of novel electroactive copolymers of poly(amic acid) (PAA) bearing pendant aniline tetramer groups were prepared via direct polycondensation from novel electroactive diamine (EDA), 4,4'-diaminodiphenyl ether (p-ODA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA). The structures of the copolymers were confirmed by FT-IR and 1H NMR measurements. Then the prepared PAA copolymers were heated at 300 °C to induce cyclization, and transformed into polyimide (PI) films. The obtained PI films exhibited excellent thermal stability and outstanding mechanical properties. The PAA copolymers films had reversible redox couples with good cycle stability. The stepwise oxidation of as-prepared PAA copolymers by ammonium persulfate is monitored by UV-vis spectroscopy. The absorption peak at 571 nm underwent a red shift when it transformed from emeraldine state to pernigraniline state. Moreover, the PAA copolymers films revealed electrochromic behaviors with a color change from yellowish at its neutral state, to green, and finally to dark blue. They also exhibited extremely high optical contrast (%ΔT) up to 63% at 700 nm, moderate coloration efficiency (CE ≈ 100 cm2 C−1) and low switching times of 3.9 s at 0.8 V and 1.3 s for fast bleaching.
Co-reporter:Hui Mao, Yongxin Li, Xincai Liu, Wanjin Zhang, Ce Wang, Salem S. Al-Deyab, Mohamed El-Newehy
Journal of Colloid and Interface Science 2011 Volume 356(Issue 2) pp:757-762
Publication Date(Web):15 April 2011
DOI:10.1016/j.jcis.2011.01.004
Novel spindle-like polypyrrole hollow nanocapsules containing Pt nanoparticles (Pt NPs/PPy composite hollow nanospindles) were successfully prepared by using beta-akaganeite (β-Fe3+O(OH,Cl)) nanospindles as templates and methanoic acid as a reducing agent. The β-Fe3+O(OH,Cl) templates can be easily obtained in ethanol/water mixing solution in the presence of thiophene and FeCl3·6H2O, and after coating by PPy shell, they can be gradually and completely etched during the reduction of H2PtCl6 into Pt nanoparticles (Pt NPs) with the average size of 3.6 nm on spindle-like polypyrrole hollow nanocapsules, which could still keep their integrality of morphologies with the thickness of PPy shell of 18–20 nm. The investigation of Pt NPs/PPy composite hollow nanospindles modified glassy carbon electrode (GCE) for the application to detect nicotinamide adenine dinucleotide (NADH) with cyclic voltammetry (CV) and amperometry indicated good linearity and sensitivity of responses in the certain range of NADH concentration. The influence of Pt NPs content to the NADH oxidation current was also studied. This new kind of unique spindle-like noble metal/conducting polymer hollow nanostructured complex can be acted as a good steady electrode material for electrocatalytic oxidation of NADH.Graphical abstractNovel spindle-like polypyrrole hollow nanocapsules containing Pt nanoparticles can be successfully prepared and acted as a good steady electrode material for electrocatalytic oxidation of NADH.Research highlights► A novel Pt NPs/PPy composite hollow nanospindles were fabricated. ► The chemical structure of the Pt NPs/PPy composite hollow nanospindles was studied. ► The composite hollow nanospindles showed good electrocatalysis oxidation of NADH.
Co-reporter:Xiaobo Ma, Wei Nie, Daocheng Pan, Xiangling Ji, Ce Wang and Wanjin Zhang
CrystEngComm 2011 vol. 13(Issue 16) pp:5243-5249
Publication Date(Web):04 Jul 2011
DOI:10.1039/C1CE05229B
Colloidal CdSe/CdS nanocrystals are synthesized at low temperatures (40–70 °C) via a two-phase approach at an environmentally friendly n-heptane–water interface. Oil-soluble cadmium myristate (Cd-MA) is used as cadmium source, while thiourea and selenourea are used as sulfur and selenium sources, respectively. First, the CdSe nanocrystals are achieved at an n-heptane–water interface with a diameter ranging from 1.77 to 1.83 nm at 40 °C. Subsequently, highly luminescent CdSe/CdS core–shell nanocrystals are synthesized using poorly reactive thiourea as sulfur source at 70 °C in a two-phase system. As-prepared core–shell nanocrystals have a quantum yield (PL QY) of up to 73% relative to coumarin 6 at room temperature. Meanwhile, the influence of CdSe core size and CdS shell thickness on PL QY and PL lifetime are also investigated.
Co-reporter:Xiaoteng Jia;Danming Chao;Libing He;Hongtao Liu;Tian Zheng
Macromolecular Research 2011 Volume 19( Issue 11) pp:
Publication Date(Web):2011 November
DOI:10.1007/s13233-011-1114-3
Co-reporter:Libing He;Danming Chao;Xiaoteng Jia;Hongtao Liu;Lei Yao
Journal of Polymer Research 2011 Volume 18( Issue 3) pp:443-448
Publication Date(Web):2011 May
DOI:10.1007/s10965-010-9435-z
By oxidative coupling polymerization approach, we have synthesized a novel electroactive polymer with alternating phenyl-capped aniline tetramer in the main chain and nitrile group in the side chain. The detailed characteristics of the as-synthesized polymer were systematically studied by Fourier-transform infrared (FTIR) spectra, nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). UV–vis spectra were used to monitor the oxidation process of the polymer. Moreover, the electrochemical behavior of the polymer was explored by cyclic voltammogram (CV), showing that the intrinsic electroactivity of the oligoaniline was maintained in the polymer and two distinct reversible oxidative states were observed. The thermogravimetric analysis (TGA) indicated that the polymer possessed good thermal resistance due to the introduction of the rigid and polar nitrile groups in side chains. The reactivity of nitrile group provides the probability of modifying and functionalizing the polymer further, and creating a series of novel functional polymers.
Co-reporter:Danming Chao;Xiaoteng Jia;Hongtao Liu;Libing He;Lili Cui;Erik B. Berda
Journal of Polymer Science Part A: Polymer Chemistry 2011 Volume 49( Issue 7) pp:1605-1614
Publication Date(Web):
DOI:10.1002/pola.24584
Abstract
We present a series of novel poly(arylene ether sulfone) copolymers containing pendant oligoaniline groups. A novel monomer containing oligoaniline, 2,6-difluorobenzoyl aniline tetramer (DFAT), was synthesized by reaction of 2,6-difluorobenzoyl chloride and parent aniline tetramer and incorporated into the aforementioned copolymers via direct copolymerization with 4,4′-dichlorodiphenyl sulfone (DCDPS), and 4,4′-isopropylidene diphenol (BPA) using N,N′-dimethylacetamide as solvent. The structures of these copolymers were confirmed by FTIR, 1H NMR, and GPC. Spectral analysis of the copolymers in different oxidation states was investigated via UV-visible spectra. The copolymers exhibited outstanding thermal stability and good solubility in various organic solvents. Their electroactivity, explored with cyclic voltammetry, was found to increase as the content of oligoaniline in the polymer increased. The electric and dielectric properties of the copolymers were also studied in detail. The electrochromic performance of the copolymers was investigated by electrochromic photographs and transmittance spectra; the color of the copolymer thin films changes from grey (at 0.0 V), to green (at 0.4 V), to blue (at 0.6 V) and to pearl blue (at 1.0 V) and the maximum transmittance change (ΔT) at 700 nm is 42.6% (90.7% 48.1%). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Co-reporter:Junyu Lei, Wei Wang, Mingxin Song, Bo Dong, Zhenyu Li, Ce Wang, Lijuan Li
Reactive and Functional Polymers 2011 71(11) pp: 1071-1076
Publication Date(Web):November 2011
DOI:10.1016/j.reactfunctpolym.2011.08.002
Co-reporter:Hui Mao, Xincai Liu, Danming Chao, Lili Cui, Yongxin Li, Wanjin Zhang and Ce Wang
Journal of Materials Chemistry A 2010 vol. 20(Issue 45) pp:10277-10284
Publication Date(Web):04 Oct 2010
DOI:10.1039/C0JM01745K
By using Ce(SO4)2·4H2O as an oxidant and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as a surfactant, unique poly(3,4-ethylenedioxythiophene) (PEDOT) nanorods with a couple of cuspate tips were successfully prepared by reverse interfacial polymerization. The morphology of these PEDOT nanorods was very regular and well-dispersed with widths and lengths from one tip to another tip mostly in the range 40–60 nm and 370–460 nm, respectively. The chemical structure and formation mechanism of PEDOT nanorods are discussed in detail by several analysis methods. AOT played an important role during the formation of PEDOT nanorods. It could be combined with Ce4+ to form a unique template for the polymerization of 3,4-ethylenedioxythiophene (EDOT) in the cylindrical micelles formed by n-hexane, H2O and AOT. Furthermore, the application of PEDOT nanorod-modified glassy carbon electrode (GCE) as an electrochemical sensor for detecting nitrite was also investigated. Due to their good dispersibility and large surface area, PEDOT nanorods exhibited good linearity and sensitivity of cyclic voltammetry (CV) responses as well as amperometric responses for electrocatalytic oxidation of nitrite. It resulted in PEDOT nanorods acting as a good steady and sensitive electrode material for detecting nitrite.
Co-reporter:E. Jin, Xiaofeng Lu, Lili Cui, Danming Chao, Ce Wang
Electrochimica Acta 2010 Volume 55(Issue 24) pp:7230-7234
Publication Date(Web):1 October 2010
DOI:10.1016/j.electacta.2010.07.029
In this work, graphene/prussian blue (PB) composite nanosheets with good dispersibility in aqueous solutions have been synthesized by mixing ferric-(III) chloride and potassium ferricyanide in the presence of graphene under ambient conditions. Transmission electron microscopy (TEM) shows that the average size of the as-synthesized PB nanoparticles on the surface of graphene nanosheets is about 20 nm. Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) patterns have been used to characterize the chemical composition of the obtained graphene/PB composite nanosheets. The graphene/PB composite nanosheets exhibit good electrocatalytic behavior to detection of H2O2 at an applied potential of −0.05 V. The sensor shows a good linear dependence on H2O2 concentration in the range of 0.02–0.2 mM with a sensitivity of 196.6 μA mM−1 cm−2. The detection limit is 1.9 μM at the signal-to-noise ratio of 3. Furthermore, the graphene/PB modified electrode exhibits freedom of interference from other co-existing electroactive species. This work provides a new kind of composite modified electrode for amperometric biosensors.
Co-reporter:Lirong Kong, Xiaofeng Lu, Xiujie Bian, Wanjin Zhang, Ce Wang
Journal of Solid State Chemistry 2010 Volume 183(Issue 10) pp:2421-2425
Publication Date(Web):October 2010
DOI:10.1016/j.jssc.2010.08.005
A simple one-step method to fabricate hierarchically porous TiO2/Pd composite hollow spheres without any template was developed by using solvothermal treatment. Pd nanoparticles (2–5 nm) were well dispersed in the mesopores of the TiO2 hollow spheres via in-situ reduction. In our experiment, polyvinylpyrrolidone played an important role in the synthetic process as the reducing agent and the connective material between TiO2 and Pd nanoparticles. HF species generated from solvothermal reaction leaded to the formation of TiO2 hollow spheres and Ostwald ripening was another main factor that affected the size and structure of the hollow spheres. The as-prepared TiO2/Pd composite hollow spheres exhibited high electrocatalytic activity towards the reduction of H2O2. The sensitivity was about 226.72 μA mM−1 cm−2 with a detection limit of 3.81 μM at a signal-to-noise ratio of 3. These results made the hierarchically porous TiO2/Pd composite a promising platform for fabricating new nonenzymic biosensors.Graphical AbstractA new one-step solvothermal method was developed to prepare Pd nanoparticles embedded hierarchically porous TiO2 hollow spheres. Due to its unique nanostructure, the prepared TiO2/Pd modified GC electrode exhibit a high sensitivity (226.72 μA mM−1 cm−2), a relatively low reduction potential (−0.2 V), a fast response time (<3 s) and a relatively low detection limit of 3.81 μM (S/N=3) towards H2O2.
Co-reporter:Lili Cui, Danming Chao, Junfeng Zhang, Hui Mao, Yongxin Li, Ce Wang
Synthetic Metals 2010 Volume 160(5–6) pp:400-404
Publication Date(Web):March 2010
DOI:10.1016/j.synthmet.2009.11.016
A new electroactive polyamide with dibenzo-18-crown-6 and well-defined oligoaniline in the main chain was synthesized through oxidative coupling polymerization. The structure of the electroactive copolymer was confirmed by FTIR, NMR spectroscopy. And its electrochemical activity was tested in 0.5 M H2SO4 aqueous solution and it shows three redox peaks. Moreover, the UV–vis absorption attenuation of the copolymer solution was found upon K+ binding, but the absorption had hardly change on Na+. We found the polymer has selectivity toward K+ ions. So it has a potential application in chemical sensors.
Co-reporter:Yang Yang, Chengcheng Zhang, Yue Xu, Haiying Wang, Xiang Li, Ce Wang
Materials Letters 2010 Volume 64(Issue 2) pp:147-150
Publication Date(Web):31 January 2010
DOI:10.1016/j.matlet.2009.10.028
TiO2 nanofibrous films with variable amounts of erbium were prepared via electrospinning. Analytical results demonstrated that the doping of erbium inhibited the phase transformation and the crystallite growth of TiO2. The doped samples were more efficient for degradation of methylene blue than TiO2, and an optimal dosage of erbium at 0.5% activated at 773 K achieved the highest degradation rate. The higher photoactivity might be attributable to the transition of 4f electrons of erbium, particle size, phase composition and the increase of the separating rate of photogenerated charges by erbium doping.
Co-reporter:Lili Cui;Danming Chao;Xiaofeng Lu;Junfeng Zhang;Hui Mao;Yongxin Li
Polymer International 2010 Volume 59( Issue 7) pp:975-979
Publication Date(Web):
DOI:10.1002/pi.2815
Abstract
A novel electroactive polymer that has alternating oligo-aniline and flexible poly(ethylene oxide) segments in the main chain has been synthesized through oxidative coupling polymerization. The chemical structure of the electroactive copolymer was confirmed using Fourier transform infrared and NMR spectroscopy measurements. The electrochemical activity of the copolymer was tested in 1.0 mol L−1 H2SO4 aqueous solution and it shows two redox peaks. Moreover, the thermal properties of the copolymer were investigated using thermogravimetric analysis. The copolymer obtained has good solubility in some common organic solvents. The most important properties of the copolymer are its dielectric ones, which were also investigated. It has a very high dielectric constant at room temperature. Copyright © 2010 Society of Chemical Industry
Co-reporter:Xiujie Bian, Xiaofeng Lu, E. Jin, Lirong Kong, Wanjin Zhang, Ce Wang
Talanta 2010 Volume 81(Issue 3) pp:813-818
Publication Date(Web):15 May 2010
DOI:10.1016/j.talanta.2010.01.020
Pt/polypyrrole (PPy) hybrid hollow microspheres were successfully prepared by wet chemical method via Fe3O4 template and evaluated as electrocatalysts for the reduction of hydrogen peroxide. The as-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), X-ray diffraction (XRD), inductive coupled plasma emission spectrum (ICP) and Fourier-transform infrared spectra (FTIR) measurements. The results exhibited that ultra-high-density Pt nanoparticles (NPs) were well deposited on the PPy shell with the mean diameters of around 4.1 nm. Cyclic voltammetry (CV) results demonstrated that Pt/PPy hybrid hollow microspheres, as enzyme-less catalysts, exhibited good electrocatalytic activity towards the reduction of hydrogen peroxide in 0.1 M phosphate buffer solution (pH = 7.0). The composite had a fast response of less than 2 s with linear range of 1.0–8.0 mM and a relatively low detection limit of 1.2 μM (S/N = 3). The sensitivity of the sensor for H2O2 was 80.4 mA M−1 cm−2.
Co-reporter:Hongnan Zhang, Zhenyu Li, Li Liu, Xiuru Xu, Zhaojie Wang, Wei Wang, Wei Zheng, Bo Dong, Ce Wang
Sensors and Actuators B: Chemical 2010 Volume 147(Issue 1) pp:111-115
Publication Date(Web):18 May 2010
DOI:10.1016/j.snb.2010.01.056
A nano-gas sensor based on Pd–SnO2 composite nanofibers is fabricated by electrospinning technique and calcination procedure. The morphology, structure and composition of the as-prepared nanofibers are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), respectively. The nano-gas sensor shows excellent hydrogen sensing properties such as high sensitivity and extremely fast response–recovery behavior (∼9 s) at a lower operation temperature (280 °C). The detection limit of approximately 4.5 ppm H2 is demonstrated. The function of adding Pd into the SnO2 nanofibers and the sensing mechanism have also been discussed in this work.
Co-reporter:Wei Wang, Zhenyu Li, Wei Zheng, Huimin Huang, Ce Wang, Jinghui Sun
Sensors and Actuators B: Chemical 2010 Volume 143(Issue 2) pp:754-758
Publication Date(Web):7 January 2010
DOI:10.1016/j.snb.2009.10.016
Certain amount of Cr2O3 has been in situ added to ZnO nanofibers during the electrospinning process and subsequent calcination to form Cr2O3-sensitized ZnO (C-s-Z) nanofibers. The morphology and structure of the as-prepared nanofibers have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS) and X-ray diffraction (XRD). The effect of the Cr2O3 component in C-s-Z nanofibers on the gas sensing properties has been evaluated by the responses to ethanol vapor. The results have showed that the C-s-Z nanofibers containing 4.5 wt% Cr2O3 exhibit the best sensing properties to ethanol vapor. The response to 1 ppm ethanol vapor is as high as 3.6, and the response and recovery time are about 1 and 5 s, respectively. In addition, the as-prepared sensors exhibit excellent selectivity and stability. These results indicate that the C-s-Z electrospun composite nanofibers can be used in fabricating high performance gas sensors.
Co-reporter:Danming Chao, Junfeng Zhang, Xincai Liu, Xiaofeng Lu, Ce Wang, Wanjin Zhang, Yen Wei
Polymer 2010 Volume 51(Issue 20) pp:4518-4524
Publication Date(Web):17 September 2010
DOI:10.1016/j.polymer.2010.03.055
Electroactive poly(amic acid), with oligoaniline in the main chain, was synthesized from macro-monomer of oligoaniline and p-phenylenediamine by oxidative coupling polymerization. The polymer characterization included Fourier-transform infrared spectra (FTIR), 1H nuclear magnetic resonance spectra (1H NMR) and gel permeation chromatography (GPC) as a determination of polymer structure, spectral analysis of different oxidation states via UV–visible spectra. Then the obtained poly(amic acid) was heated at 260 °C to induce cyclization, and transformed into polyimide materials. X-ray powder diffraction (XRD) and thermogravimetric analysis (TGA) were used for the characterization of poly(amic acid) and polyimide materials. Moreover, poly(amic acid) and polyimide were tested in 1.0 M H2SO4 aqueous solution by cyclic voltammetry and they showed different electrochemical activity from each other. The prepared poly(amic acid) and polyimide doped with HCl exhibit a large enhancement in the dielectric constant in comparison to that of traditional polymers, ascribed to the improvement in charge delocalization of the polymers by introduction of the conjugated oligoaniline segments.
Co-reporter:Wei Wang, Zhenyu Li, Wei Zheng, Jie Yang, Hongnan Zhang, Ce Wang
Electrochemistry Communications 2009 Volume 11(Issue 9) pp:1811-1814
Publication Date(Web):September 2009
DOI:10.1016/j.elecom.2009.07.025
Pd (IV)-doped CuO oxide composite nanofibers (PCNFs) have been successfully fabricated via electrospinning and then employed to construct an amperometric non-enzymatic glucose sensor. The PCNFs based glucose sensors display distinctly enhanced electrocatalytic activity towards the oxidation of glucose, showing significantly lower overvoltage (0.32 V) and ultrafast (1 s) and ultrasensitive current (1061.4 μA mM−1 cm−2) response with a lower detection limit of 1.9 × 10−8 M (S/N = 3). Additionally, excellent selectivity, reproducibility and stability have also been obtained. These results indicate that PCNFs are promising candidates for amperometric non-enzymatic glucose detection.
Co-reporter:Hui Mao, Xiaofeng Lu, Ce Wang, Wanjin Zhang
Electrochemistry Communications 2009 Volume 11(Issue 3) pp:603-607
Publication Date(Web):March 2009
DOI:10.1016/j.elecom.2008.12.057
Poly(3,4-ethylenedioxythiophene (PEDOT)/β-Fe3+O(OH,Cl) nanospindles dispersed in ethanol were dropped on a glassy carbon electrode (GCE) and their electrocatalytic properties towards oxidation of KI and reduction of KIO3 were investigated by cyclic voltammetry (CV). Compared to bare GCE, the anodic and cathodic response currents were greatly enhanced due to the spindle-like morphology which leaded to the increase of surface area. The effect of scanning rate was also studied and obtained diffusion control to the nature of oxidation process of KI and surface control to the nature of reduction process of KIO3, respectively. PEDOT/β-Fe3+O(OH,Cl) nanospindles modified GCE had good stability and repeatability of CV responses and the used modified electrode could be cleaned easily by ultrasonic for several minutes. This new kind of conducting polymer/inorganic composite nanomaterials could act as a good steady and convenient electrode material for detecting iodic compounds or some other kinds of compounds.
Co-reporter:Lirong Kong, Xiaofeng Lu, E Jin, Shan Jiang, Xiujie Bian, Wanjin Zhang, Ce Wang
Journal of Solid State Chemistry 2009 Volume 182(Issue 8) pp:2081-2087
Publication Date(Web):August 2009
DOI:10.1016/j.jssc.2009.05.021
Polyaniline (PANI)/Fe3O4 composite hollow spheres have been successfully synthesized in one step using sulfonated polystyrene (PS) spheres as templates. The magnetic PANI hollow spheres were used as supports for noble metal nanoparticles (NPs) such as Au and Pd. The morphology, composition and magnetic properties of the resulting products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, inductively coupled plasma (ICP) atomic spectra and vibrating sample magnetometer. The catalytic activity of magnetic PANI/Au composite shells on the oxidation of dopamine was investigated by cyclic voltammetry. The obtained results provide our product with a practical application for the detection of dopamine. On the other hand, the catalytic activity of magnetic PANI/Pd composite shells on the reduction of 4-nitroaniline was investigated by spectroscopic methods and compared with Pd/C catalyst which was already widely used in industrial production.TEM image of PANI/Fe3O4 hollow spheres which can be used as supports for a variety of catalysts such as noble metal nanoparticles. Based on the unique properties of polyaniline hollow spheres and Fe3O4 NPs, we designed the synthesis of polyaniline/Fe3O4 NPs composite hollow spheres as supports for catalysts such as noble metal NPs. As a result, the obtained composites exhibit enhanced catalytic activities and can be easily separated from reaction mixture by using an NdFeB permanent magnet.
Co-reporter:Yang Yang, Haiying Wang, Xiang Li, Ce Wang
Materials Letters 2009 Volume 63(Issue 2) pp:331-333
Publication Date(Web):31 January 2009
DOI:10.1016/j.matlet.2008.10.037
Mesoporous W6+-doped TiO2 thin films photocatalysts were prepared via electrospinning and sol–gel chemistry, employing a triblock copolymer as structure-directing agent, and were characterized by SEM, TEM, XRD as well as N2 adsoption/desorption isotherm. The photocatalytic activity of the films was investigated by employing the methylene blue (MB) as probe. In this study, 3% was the most suitable content of W6+ in TiO2, at which the recombination of photoinduced electrons and holes could be effectively inhibited. In the mean time, making the photocatalysts at nanoscale and with mesopores in the films could produce more reactive sites to adsorbe and oxidize pollutants.
Co-reporter:Wei Wang, Zhenyu Li, Li Liu, Hongnan Zhang, Wei Zheng, Yu Wang, Huimin Huang, Zhaojie Wang, Ce Wang
Sensors and Actuators B: Chemical 2009 Volume 141(Issue 2) pp:404-409
Publication Date(Web):7 September 2009
DOI:10.1016/j.snb.2009.06.029
The humidity sensitive characteristics of sensors fabricated from pure ZnO nanofibers and LiCl-doped ZnO composite fibers by screen-printing on ceramic substrates with carbon interdigital electrodes have been investigated. The best result is obtained for 1.2 wt% LiCl-doped sample, which exhibits high humidity sensitivity, rapid response and recovery, small hysteresis, excellent linearity, and good reproducibility. The impedance of the sensor varies more than four orders of magnitude during the whole relative humidity (RH) from 11 to 95%. The response time and recovery time of the sensor is about 3 and 6 s, respectively. These results make our product a good candidate in fabricating high performance humidity sensors.
Co-reporter:Wei Zheng, Xiaofeng Lu, Wei Wang, Zhenyu Li, Hongnan Zhang, Yu Wang, Zhaojie Wang, Ce Wang
Sensors and Actuators B: Chemical 2009 Volume 142(Issue 1) pp:61-65
Publication Date(Web):12 October 2009
DOI:10.1016/j.snb.2009.07.031
In2O3 nanofibers with diameters of around 60 nm have been fabricated by electrospinning with a solution containing both poly (vinyl pyrrolidone) (PVP) and indium nitrate, followed by calcination in air at 700 °C. Without further adding catalysts or doping other metal oxides, the sensor based on the as-prepared indium oxide (In2O3) nanofibers showed high response and selectivity, fast response and recovery time towards ethanol gas. The simple preparation and excellent properties significantly advance the viability of electrospun gas sensors.
Co-reporter:Xiaofeng Song, Qi Qi, Tong Zhang, Ce Wang
Sensors and Actuators B: Chemical 2009 Volume 138(Issue 1) pp:368-373
Publication Date(Web):24 April 2009
DOI:10.1016/j.snb.2009.02.027
A fast, simple and reliable humidity sensor based on ion-doped SnO2 nanofibers has been developed by screen-printing on ceramic substrates with Ag–Pd interdigital electrodes in this research. The optimized results show that the impedance of the sensor decreases by more than five orders of magnitude with increasing relative humidity (RH) from 11% to 95%, the response and recovery time of the sensor are about 5 and 6 s, respectively. Compared to the previous electrical conductivity-based SnO2 humidity sensors, the proposed sensor exhibits higher humidity sensitivity, more rapid response and recovery, smaller hysteresis, and better linearity and stability.
Co-reporter:Hongnan Zhang, Zhenyu Li, Li Liu, Ce Wang, Yen Wei, Alan G. MacDiarmid
Talanta 2009 Volume 79(Issue 3) pp:953-958
Publication Date(Web):15 August 2009
DOI:10.1016/j.talanta.2009.05.035
Mg2+ and Na+ doped rutile TiO2 nanofibers have been prepared through in situ electrospinning technique and calcination with poly(vinyl pyrrolidone) (PVP) nanofibers as sacrificed template. The as-prepared composite nanofibers are spin-coated onto a ceramic substrate with three pairs of carbon interdigital electrodes to measure its humidity sensing behaviors. The product exhibits high-speed response (2 s) and recovery (1 s) for detecting moisture. Additionally, under UV irradiation, a water contact angle (θ) of nearly 0° has been observed based on the product, providing our humidity sensor with the anti-fogged properties.
Co-reporter:Haiying Wang, Yu Wang, Yang Yang, Xiang Li, Ce Wang
Materials Research Bulletin 2009 44(2) pp: 408-414
Publication Date(Web):
DOI:10.1016/j.materresbull.2008.05.001
Co-reporter:Wei Zheng, Zhenyu Li, Hongnan Zhang, Wei Wang, Yu Wang, Ce Wang
Materials Research Bulletin 2009 44(6) pp: 1432-1436
Publication Date(Web):
DOI:10.1016/j.materresbull.2008.12.013
Co-reporter:Xiaofeng Song, Zhaojie Wang, Zhenyu Li, Ce Wang
Journal of Colloid and Interface Science 2008 Volume 327(Issue 2) pp:388-392
Publication Date(Web):15 November 2008
DOI:10.1016/j.jcis.2008.02.070
This work describes the potential capability of ultrafine porous carbon fibers (UPCF) prepared via electrospinning in the removal of SO2 from a mixture gas stream. A series of conventional PCF (CPCF) and ultrafine PCF (UPCF) were produced under the identical conditions and UPCF was also modified. Compared to the CPCF, experimental results showed that the UPCF had a better adsorption capacity for SO2 due to its higher surface area and microporous volume. After the modification of the UPCF, adsorption capacities of UPCF for SO2 were improved further via increasing the N-containing amount of UPCF and substrate which was followed by few changes in its specific surface area. The optimum concentration of modified reagent is 10%. From the results of the fatigue test, it has been found that both the UPCF and the modified UPCF showed a good durability.This work describes the potential capability of ultrafine porous carbon fiber prepared via electrospinning in the removal of SO2. The following SEM micrograph shows the morphology of ultrafine porous carbon fibers.
Co-reporter:Yiyang Zhao, Haiying Wang, Xiaofeng Lu, Xiang Li, Yang Yang, Ce Wang
Materials Letters 2008 Volume 62(Issue 1) pp:143-146
Publication Date(Web):15 January 2008
DOI:10.1016/j.matlet.2007.04.096
Refining mesoporous silica nanofibers were fabricated by electrospinning method. A triblock copolymer (Pluronic, P123, H(C2H5O)20(C3H7O)70(C2H5O)OH) was used as the structure direction agent and polyvinyl pyrrolidone (PVP) was employed to prepare refining nanofibers. SEM images showed that the refining fibers had an average diameter about 200–300 nm with smooth surface. FT-IR spectrum and TGA curve proved that P123 and PVP were removed from the fibers after a thermal treatment. It was found that the obtained silica nanofibers had mesoporous structure. The pore structures were characterized by XRD and the N2 adsorption–desorption isotherm.
Co-reporter:Xiaofeng Song, Lei Jun, Zhenyu Li, Shangyu Li, Ce Wang
Materials Letters 2008 Volume 62(17–18) pp:2681-2684
Publication Date(Web):30 June 2008
DOI:10.1016/j.matlet.2008.01.014
A simple synthetic route for fabricating continuous Ag shell on electrospun polyacrylonitrile (PAN) nanofibers has been presented via an improved electroless plating method. To avoid the complex steps (wet surface activation, pre-treatment) of the electroless plating methods reported before, UV photoreduction is used to fabricate dense Ag nanoparticles on the outer surfaces of PAN nanofibers. These Ag nanoparticles act as seeds in the following metal electroless plating step for the growth of continuous Ag shell. Additionally, our method can be easily applied to synthesize other metallic shell on the outer surfaces of PAN nanofibers with Ag nanoparticles as seeds.
Co-reporter:Wei Zheng, Zhenyu Li, Fan Yang, Xiaofeng Song, Hongnan Zhang, Yongben Liu, Ce Wang
Materials Letters 2008 Volume 62(8–9) pp:1448-1450
Publication Date(Web):31 March 2008
DOI:10.1016/j.matlet.2007.08.083
In this paper, a simple and effective route for the preparation of (1D) Ag-TCNQ microstructures has been demonstrated by simply dissolving silver nitrate and 7, 7, 8, 8-tetracyanoquindimethane (TCNQ) into N, N-dimethyl formamide (DMF) solution. Herein, DMF was used as both the solvent and the reducer for silver nitrate. Transmission electron microscope (TEM) and scanning electron microscope (SEM) have been used to characterize the morphologies of products. X-ray diffraction pattern (XRD) and Fourier transform infrared spectroscopy (FTIR) proved that the obtained products were in the form of the Ag -TCNQ phase I. The formation mechanism of products and the electrical properties of products were investigated.
Co-reporter:Haiying Wang, Yang Yang, Yu Wang, Xiang Li, Shengya Feng, Ce Wang
Materials Science and Engineering: B 2008 Volume 147(Issue 1) pp:69-73
Publication Date(Web):25 January 2008
DOI:10.1016/j.mseb.2007.11.003
Co-reporter:Jieyu Liu;Yong Min;Jingyu Chen;Hongwei Zhou
Macromolecular Rapid Communications 2007 Volume 28(Issue 2) pp:215-219
Publication Date(Web):16 JAN 2007
DOI:10.1002/marc.200600607
In this article, electrospinning technique has been demonstrated for the synthesis of ultra-low dielectric constant polyimide fiber membranes. Poly(amic acid) fiber membranes have been prepared as precursor. After the treatment of thermal imidization, ultra-low dielectric constant polyimide fibers membranes can be obtained. The morphologies and structures of precursors and products are characterized by scanning electron microscopy (SEM), Fourier transmission infrared (FTIR) spectra, and a radio frequency (RF) impedance/capacitance material analyzer. The DK of the as-prepared polyimide membrane ranges from 1.53 to 1.56, which could be applied in the electronic packaging industry.
Co-reporter:Hang Lin, Jun Tang, Ce Wang
Materials Letters 2007 Volume 61(8–9) pp:1637-1640
Publication Date(Web):April 2007
DOI:10.1016/j.matlet.2006.07.090
Co-reporter:Yang Yang, Haiying Wang, Xiaofeng Lu, Yiyang Zhao, Xiang Li, Ce Wang
Materials Science and Engineering: B 2007 Volume 140(1–2) pp:48-52
Publication Date(Web):25 May 2007
DOI:10.1016/j.mseb.2007.03.010
Carbon/CdS coaxial nanofibers (NFs) have been prepared using polyacrylonitrile (PAN)/CdS composite NFs as precursors. The synthesis strategy involves immersing the as-spun PAN fibers into cadmium acetate aqueous solution, followed by reaction with H2S gas and carbonization. SEM and TEM showed the morphology of the obtained coaxial NFs. The structures were examined by XRD, FT-IR and Raman spectra. The NFs displayed photoluminescence and conductive properties which were characterized by room-temperature photoluminescent spectra and standard four-probe method.
Co-reporter:Daliang Zhang;Qidong Zhao;Yen Wei;Wanjin Zhang;Xiaofeng Lu
Macromolecular Rapid Communications 2006 Volume 27(Issue 1) pp:76-80
Publication Date(Web):19 DEC 2005
DOI:10.1002/marc.200500602
Summary: We show in this communication that large-scale necklace-like single-crystalline tetragonal perovskite PbTiO3 nanowires can be obtained via a simple electrospinning method. The morphology and the crystal structure are investigated by SEM, XRD, and HRTEM. The length of the necklace-like PbTiO3 nanowires is from tens to several tens of micrometers, the wider the diameter of it is between 100 and 200 nm and the thinner the part is between 20 and 50 nm. The necklace-like PbTiO3 nanowires exhibit high surface photovoltage under the action of external electric field, which is probably applicable in displaying photoelectric devices of heterojunction structure.
Co-reporter:Xiaofeng Lu;Qidong Zhao;Xincai Liu;Dejun Wang;Wanjin Zhang;Yen Wei
Macromolecular Rapid Communications 2006 Volume 27(Issue 6) pp:430-434
Publication Date(Web):6 MAR 2006
DOI:10.1002/marc.200500810
Summary: We demonstrate in this communication that large-scale coaxial nanocables of polypyrrole (PPy)/TiO2 can be obtained via three steps: (1) synthesis of TiO2 nanofibers by electrospinning; (2) physical adsorption Fe3+ oxidant on the surface of TiO2 nanofibers; (3) followed by polymerization of pyrrole (from vapor) on the surface of TiO2 nanofibers. During the synthesis, the PPy formed on TiO2 nanofibers as a template and formed PPy/TiO2 coaxial nanocables. TEM image proved that PPy (20 nm thickness) covered the surface of TiO2 nanofibers. Fourier-transform infrared (FTIR), X-ray photoelectron spectra (XPS), and X-ray diffraction patterns (XRD) characterized the chemical structure of the coaxial nanocables. Surface photovoltage spectroscopy (SPS) revealed the surface properties of the PPy/TiO2 coaxial nanocables.
Co-reporter:Huimin Huang;Zhenyu Li
Macromolecular Rapid Communications 2006 Volume 27(Issue 2) pp:152-155
Publication Date(Web):16 JAN 2006
DOI:10.1002/marc.200500627
Summary: Copper/poly(vinyl alcohol) (PVA) nanocables have been successfully obtained by electrospinning a PVA-protected copper nanoparticle solution. The molar ratio of copper ions to PVA (in terms of VA repeating units) plays an important role in the formation of copper/PVA nanocables. The average diameter of the copper cores and PVA shells is about 100 and 400 nm, respectively. The structures of the copper/PVA nanocables are characterized by transmission electron microscopy (TEM) and their formation is confirmed by scanning electron microscopy (SEM).
Co-reporter:Xiaofeng Lu, Xincai Liu, Wanjin Zhang, Ce Wang, Yen Wei
Journal of Colloid and Interface Science 2006 Volume 298(Issue 2) pp:996-999
Publication Date(Web):15 June 2006
DOI:10.1016/j.jcis.2006.01.032
We show in this communication that large-scale synthesis of orthorhombic WO3 nanofibers can be obtained via a simple electrospinning method. The morphology and the crystal structure are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FTIR, X-ray diffraction patterns (XRD) and X-ray photoelectron spectra (XPS) spectra. SEM and TEM images showed that the diameter of the obtained WO3 nanofibers is between 100 and 500 nm. The structure of the obtained WO3 nanofibers was characterized by FTIR, XRD, and XPS spectra. The photoluminescence of the obtained WO3 nanofibers were also investigated.An electrospinning method to the synthesis of tungsten oxide nanofibers has been developed. It has been shown that the fibers are uniformly composed of some grains, which are proved by TEM image.
Co-reporter:Xiaohui Cai;Guangshan Zhu;Weiwei Zhang;Huanyu Zhao;Shilun Qiu;Yen Wei
European Journal of Inorganic Chemistry 2006 Volume 2006(Issue 18) pp:
Publication Date(Web):1 AUG 2006
DOI:10.1002/ejic.200600339
Ordered meso/macroporous hierarchical silica materials have been prepared using block copolymer P123 (EO20PO70EO20) and an inverse carbon replica of diatom as templates. The silica wall of the diatom was replaced by ordered mesoporous silica, while the micron-sized diatom architecture was replicated by using an inverse carbon replication technique. The mesoporous silica was found to have macroporous structures of both columnar and discoid diatom templates. The presence of hierarchical meso/macroporous systems was confirmed by the results from scanning and transmission electron microscopy, powder X-ray diffraction, and nitrogen adsorption–desorption studies. The materials with columnar and discoid morphologies have BET surface areas of about 400 m2 g–1. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Co-reporter:Xiufeng Hao;Zhenyu Li;Tiecun Shang;Xiaofeng Lu;Qingbiao Yang;Lijuan Li;Yiyang Zhao
Journal of Applied Polymer Science 2006 Volume 102(Issue 3) pp:2889-2893
Publication Date(Web):23 AUG 2006
DOI:10.1002/app.24731
Polyacrylonitrile colloidal microspheres have been successfully prepared with different concentrations of electrospraying polyacrylonitrile solutions. The morphology of the colloidal spheres has two kinds of structures and is strongly affected by electrospray-ionization parameters, such as the polymer concentration, applied voltage, and distance between the electrodes. The solvent can also affect the morphology of polyacrylonitrile. The optimum conditions for preparing colloidal spheres have been found, and differential scanning calorimetry results indicate that polyacrylonitrile colloid spheres are amorphous. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2889–2893, 2006
Co-reporter:Xiaofeng Lu;Yuwei Jin
Journal of Applied Polymer Science 2006 Volume 102(Issue 6) pp:6017-6022
Publication Date(Web):28 SEP 2006
DOI:10.1002/app.25197
This study described the preparation of discontinuous fibers of poly (N-vinylpyrrolidone) (PVP) containing metalloporphyrin (Manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin pentachloride) molecules using electrospinning method. SEM images showed that before adding the metalloporphyrin molecules, the electrospun nanofibers are straight and smooth, while after adding metalloporphyrin molecules into the PVP solutions, the SEM images clearly showed that there were two different types of fibers: the thinner fibrous phase and the thicker discontinuous fibers. The chemical composition of the resulting PVP/metalloporphyrin composite fibers was characterized by Fourier-transform infrared (FTIR) and energy dispersive X-ray (EDX) analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 6017–6022, 2006
Co-reporter:Haiying Wang, Xiaofeng Lu, Yiyang Zhao, Ce Wang
Materials Letters 2006 Volume 60(Issue 20) pp:2480-2484
Publication Date(Web):September 2006
DOI:10.1016/j.matlet.2006.01.021
ZnS:Cu/Poly(vinyl alcohol) (PVA) composite nanofibers have been successfully prepared by electrospinning technique. The formation of ZnS:Cu/PVA nanofibers were carried out by reacting H2S with Zn(AC)2:Cu/PVA nanofibers, which were electrospun from the mixture aqueous solution of Zn(Ac)2, Cu(Ac)2 and PVA. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray-diffraction (XRD) analyses revealed that the morphology of the ZnS:Cu/PVA nanofibers consists of the dispersion of ZnS:Cu nanopaticles with cubic structure in PVA nanofibers. The coordinations between –OH and Zn2+:Cu were characterized by infrared spectroscopy. The photoluminescence spectroscopy studies showed the significant difference between the ZnS/PVA fibers and the ZnS:Cu/PVA fibers. The luminescence decay time measure further invested that the Cu was doped in the ZnS crystal.
Co-reporter:X. Lu;Y. Zhao;C. Wang
Advanced Materials 2005 Volume 17(Issue 20) pp:
Publication Date(Web):15 SEP 2005
DOI:10.1002/adma.200500196
PbS nanoparticles dispersed in polymer-fiber matrices by electrospinning are presented (see Figure). These PbS nanoparticles are roughly spherical in shape, each with a diameter of approximately 5 nm, and do not aggregate. This method will open up a wide route to functionalizing surfaces which can enable the fabrication of new types of optical, electric, and magnetic devices.
Co-reporter:Xiaofeng Lu;Yiyang Zhao;Yen Wei;Xiaofeng Lu;Yiyang Zhao;Yen Wei
Macromolecular Rapid Communications 2005 Volume 26(Issue 16) pp:1325-1329
Publication Date(Web):3 AUG 2005
DOI:10.1002/marc.200500300
Summary: A controlled fabrication of rod-like nanostructures of cadmium sulfide (CdS) incorporated into polymer fiber matrices has been developed by an electrospinning method. Here, poly(vinyl pyrrolidone) (PVP) was used as a polymer capping reagent, utilizing the interactions of cadmium ions with the carbonyl groups in the PVP molecules. The formation of CdS nanorods inside the PVP was carried out via the reaction of Cd2+ with H2S. SEM images showed that the electrospun films of PVP/CdS are composed of fibers with a diameter between 100 and 900 nm. TEM proved that most of the CdS nanorods are incorporated in the PVP fibrous film. The diameter of the rod is about 50 nm and the length is from 100 to 300 nm.
Co-reporter:Y. Y. Zhao;Q. B. Yang;X. F. Lu;C. Wang;Y. Wei
Journal of Polymer Science Part B: Polymer Physics 2005 Volume 43(Issue 16) pp:2190-2195
Publication Date(Web):30 JUN 2005
DOI:10.1002/polb.20506
Polyacrylamide (PAAm) with ultrahigh molecular weight of 9 × 106 g/mol has been processed by means of electrospinning, to afford products with a variety of morphologies, including polymer colloids, beaded fibers, smooth fibers, and ribbons. These morphologies can be controlled by a minute change of solution concentration in a small concentration range (0.3–3.0 wt %), because of the high molecular weight of the polymer. Under our experimental conditions, no electrospun product was obtained at the concentrations below 0.3 wt %. Beaded fibers and smooth fibers formed at the concentrations between 0.3 and 0.7 wt %. At concentrations between 0.7 and 2.0 wt %, smooth fibers and ribbons coexisted. At concentrations above 2.0 wt %, ribbons were the only product. Special morphologies such as triangular beads, helical fibers, and zigzag ribbons were also observed. With a lower molecular weight PAAm, branched fibers were found in the product. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2190–2195, 2005
Co-reporter:Guangshan Zhu Dr. ;Yahong Zhang;Na Guo;Yiyang Zhao;Runwei Wang;Shilun Qiu;Yen Wei ;Ray H. Baughman
Chemistry - A European Journal 2004 Volume 10(Issue 19) pp:
Publication Date(Web):10 AUG 2004
DOI:10.1002/chem.200400288
A large surface-to-volume ratio is a prerequisite for highly effective catalysts. Making catalysts in the form of nanoparticles provides a good way to achieve the aim. However, agglomeration of nanoparticles during the preparation and utilization of nanocatalysts remains a formidable problem. Here, we present a novel approach in which nano units of catalysts are formed in the matrix of a colloidal carrier, with assistance of a cross-linking agent, and then grow out of the carrier upon calcination at high temperature. This ensures that the catalysts not only do not agglomerate, but also have a low cost and high catalytic efficiency due to the large surface-to-volume ratio and the absence of carbon deposition. The technique is demonstrated by the successful preparation of a binary nanocatalyst that consists of a silica nanoparticle core and a sulfated zirconia (SZ) nanocrystal shell (JML-1). The synthesis was achieved by converting sulfated zirconia (SZ) and silica solutions into a composite gel by means of sol–gel processing in the presence of triethoxysilane as the cross-linking agent, followed by heating at 50 °C and calcining at 550 °C. Relative to other catalysts, such as pure SZ, non-nanodispersed SZ over silica (SZ/SiO2), and zeolites Y, Beta, and ZSM-5, JML-1 exhibits superior catalytic activity in many reactions. For example, the activity of JML-1 in the production of gasoline by alkylation of 1-butene with isobutene remained at 95 % or higher after 20 h of reaction and was over 90 % after being regenerated five times. In sharp contrast, SZ and SZ/SiO2 give a high activity only for 2 h and the initial activity of zeolites Beta and ZSM-5 are about 88 and 60 %, respectively. These findings demonstrate that non-agglomerated nanoparticles anchored onto a carrier surface can be prepared and the technique provides a versatile route to new highly effective nanocatalyst systems.
Co-reporter:Guangdi Nie, Xiaofeng Lu, Maoqiang Chi, Yun Zhu, Zezhou Yang, Na Song, Ce Wang
Electrochimica Acta (20 March 2017) Volume 231() pp:
Publication Date(Web):20 March 2017
DOI:10.1016/j.electacta.2017.02.037
•Hierarchical α-Fe2O3 nanotube@MnO2 nanosheet core-shell networks were prepared.•The mass ratio of MnO2 to α-Fe2O3 can be easily controlled.•The α-Fe2O3@MnO2 heterostructures exhibited improved supercapacitive property.The incompetency of conventional single-phase electrode materials remains a stumbling block for making further breakthroughs in high-performance supercapacitors. In this work, α-Fe2O3 nanotube@MnO2 nanosheet hierarchical networks with tunable mass ratio of MnO2 to α-Fe2O3 are prepared via a simple two-step method for supercapacitor electrodes. The α-Fe2O3@MnO2 core-shell heterostructures, especially the FM10020 containing 60.1 wt% of MnO2, exhibit a larger specific capacitance of 289.9 F g−1 at 1.0 A g−1, a better rate capability of 40.8% at 5.0 A g−1 and a higher cycling stability of 85.3% after 1200 cycles than the pure MnO2, highlighting the advantages of such unique configuration accompanied by the synergistic effect. It is believed that these intriguing results will provide an alternative way for the construction of metal oxide-based composite nanostructures with improved electrochemical performance.Hierarchical α-Fe2O3 nanotube@MnO2 nanosheet networks with tunable mass ratio between MnO2 and α-Fe2O3 are prepared via a simple two-step method for high-performance supercapacitor electrodes.
Co-reporter:Xiuru Xu, Min Yin, Na Li, Wei Wang, Bolun Sun, Ming Liu, Dongwei Zhang, Zhenyu Li, Ce Wang
Talanta (15 May 2017) Volume 167() pp:638-644
Publication Date(Web):15 May 2017
DOI:10.1016/j.talanta.2017.03.013
Co-reporter:Ziqiao Jiang, Mingying Yin, Ce Wang
Materials Letters (1 May 2017) Volume 194() pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.matlet.2017.02.031
•Ca2+/Au co-doped SnO2 nanofibers were successfully synthesized for the first time.•Ca2+/Au co-doped SnO2 nanofibers showed a high response to acetone at 180 °C.•Ca2+/Au co-doped SnO2 nanofibers exhibited a rapid response/recovery behavior and good selectivity to acetone.•The synergistic effect of Ca2+ and Au co-doping plays a key role in the enhancement of sensing properties.In this work, a novel acetone sensing material, Ca2+/Au co-doped SnO2 nanofibers (atom ratio of Ca/Au/Sn is 1:5:100), have been successfully synthesized via single-capillary electrospinning and calcination procedure. The morphologies, crystal structures and chemical compositions of nanofibers were characterized. Gas sensing investigations reveal that Ca2+/Au co-doped SnO2 nanofibers exhibit a high response, rapid response-recovery behavior and good selectivity to acetone at a low operating temperature (180 °C). These prominent sensing properties are attributed to the unique one-dimensional (1D) structure of nanofibers and synergistic effect of Ca2+ and Au co-doping. The results demonstrate that Ca2+/Au co-doped SnO2 nanofibers can be used as a promising material for selective detection of acetone.
Co-reporter:Guangdi Nie, Liang Zhang, Xiaofeng Lu, Xiujie Bian, Weining Sun and Ce Wang
Dalton Transactions 2013 - vol. 42(Issue 38) pp:NaN14013-14013
Publication Date(Web):2013/07/15
DOI:10.1039/C3DT51489G
CuS-graphene nanosheet (GNS) composites with well-defined morphology have been successfully fabricated via a simple one-pot hydrothermal route by using thioacetamide (TAA) as both the sulfur source and reducing agent. The as-prepared CuS-GNS composites with an appropriate content of graphene exhibited an even higher peroxidase-like catalytic activity than pristine CuS nanoparticles in acetate buffer solution (pH = 4.0), which provided a facile method for the colorimetric detection of hydrogen peroxide (H2O2). It was calculated that H2O2 could be detected as low as 1.2 μM (S/N = 3) with a wide linear range from 2.0 to 20.0 μM (R2 = 0.992), indicating that the as-prepared catalyst as an artificial peroxidase is promising for application in biosensors and environmental monitoring.
Co-reporter:Weining Sun, Xiaofeng Lu, Yan Tong, Junyu Lei, Guangdi Nie and Ce Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 19) pp:NaN6746-6746
Publication Date(Web):2014/02/20
DOI:10.1039/C3TA15441F
In this report, a palladium/polypyrrole/polyacrylonitrile (Pd/PPy/PAN) composite nanofiber membranes was synthesized by a one-pot redox polymerization process between pyrrole monomers and Na2PdCl4 in the presence of electrospun PAN nanofibers, without the introduction of any other surfactants or reductants. The as-prepared Pd/PPy/PAN nanofiber membrane exhibited good catalytic performance towards hydrogen generation from the hydrolysis of ammonia borane (AB). The apparent activation energy (Ea) was calculated to be about 33.5 kJ mol−1. In addition, the Pd nanoparticles (Pd NPs) were encapsulated in PPy layers on the surface of the PAN nanofibers, enabling the catalyst to be stable against poisoning and easily separated from the suspension system. The catalytic activity does not weaken after five cycles. This study indicated that the obtained Pd/PPy/PAN composite nanofiber membrane could be applied as an alternative in exploring new catalysts for hydrogen generation, as hydrogen is an important fuel as a clean power source.
Co-reporter:Zhaojie Wang, Zhenyu Li, Xiuru Xu, Tingting Jiang, Hongnan Zhang, Wei Wang and Ce Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 2) pp:NaN215-215
Publication Date(Web):2012/09/17
DOI:10.1039/C2TC00101B
One-dimensional (1D) semiconducting nanostructures, as both interconnections and functional units in fabricating electronic, biological/chemical sensors, optoelectronic, electrochemical, and electromechanical devices, attract immense interest. However, all those 1D semiconducting nanostructures are sensitive to both volatile organic compounds (VOFs) and relative humidity (RH), causing the instability of those devices operated in air (except in biological/chemical sensors). Herein, we demonstrated an effective route to not only stabilize 1D semiconducting nanostructures in air but also maintain their electrical properties by constructing 1D isomeric semiconducting nanorods on 1D semiconducting nanostructures to form 1D isomeric and hierarchical semiconducting nanostructures. 1D isomeric and hierarchical TiO2 nanostructures (IHTNs) were chosen as a model, both excellent air stability and good electrical properties can be achieved. With such IHTNs as building blocks, a stable field-effect transistor has been realized.
Co-reporter:Tingting Jiang, Zhaojie Wang, Zhenyu Li, Wei Wang, Xiuru Xu, Xincai Liu, Jinfeng Wang and Ce Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 17) pp:NaN3025-3025
Publication Date(Web):2013/03/08
DOI:10.1039/C3TC00370A
This paper describes the exploration of a synergic effect within n-type inorganic–p-type organic nano-hybrids in gas sensors. One-dimensional (1D) n-type SnO2–p-type PPy composite nanofibers were prepared by combining the electrospinning and polymerization techniques, and taken as models to explore the synergic effect during the sensing measurement. Outstanding sensing performances, such as large responses and low detection limits (20 ppb for ammonia) were obtained. A plausible mechanism for the synergic effect was established by introducing p–n junction theory to the systems. Moreover, interfacial metal (Ag) nanoparticles were introduced into the n-type SnO2–p-type PPy nano-hybrids to further supplement and verify our theory. The generality of this mechanism was further verified using TiO2–PPy and TiO2–Au–PPy nano-hybrids. We believe that our results can construct a powerful platform to better understand the relationship between the microstructures and their gas sensing performances.
Co-reporter:Hui Mao, Xincai Liu, Danming Chao, Lili Cui, Yongxin Li, Wanjin Zhang and Ce Wang
Journal of Materials Chemistry A 2010 - vol. 20(Issue 45) pp:NaN10284-10284
Publication Date(Web):2010/10/04
DOI:10.1039/C0JM01745K
By using Ce(SO4)2·4H2O as an oxidant and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as a surfactant, unique poly(3,4-ethylenedioxythiophene) (PEDOT) nanorods with a couple of cuspate tips were successfully prepared by reverse interfacial polymerization. The morphology of these PEDOT nanorods was very regular and well-dispersed with widths and lengths from one tip to another tip mostly in the range 40–60 nm and 370–460 nm, respectively. The chemical structure and formation mechanism of PEDOT nanorods are discussed in detail by several analysis methods. AOT played an important role during the formation of PEDOT nanorods. It could be combined with Ce4+ to form a unique template for the polymerization of 3,4-ethylenedioxythiophene (EDOT) in the cylindrical micelles formed by n-hexane, H2O and AOT. Furthermore, the application of PEDOT nanorod-modified glassy carbon electrode (GCE) as an electrochemical sensor for detecting nitrite was also investigated. Due to their good dispersibility and large surface area, PEDOT nanorods exhibited good linearity and sensitivity of cyclic voltammetry (CV) responses as well as amperometric responses for electrocatalytic oxidation of nitrite. It resulted in PEDOT nanorods acting as a good steady and sensitive electrode material for detecting nitrite.
Co-reporter:Xiaoteng Jia, Danming Chao, Erik B. Berda, Songhao Pei, Hongtao Liu, Tian Zheng and Ce Wang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 45) pp:NaN18324-18324
Publication Date(Web):2011/10/14
DOI:10.1039/C1JM14047G
A novel, well-defined multifunctional polyamide bearing pendent aniline tetramer groups has been synthesized via low temperature solution polycondensation. The simultaneous presence of these two functional groups allows the polyamide to display the properties of azo-chromophore and oligoaniline, such as photoinduced birefringence and reversible electroactivity. The electrochromic performance of the polyamide shows the optical change in absorptivity depends on the various redox states of oligoaniline upon electrochemical switching. It is well known that a change in absorptivity is accompanied by a concomitant change in refractive index. By taking advantage of this effect and using the single step fabrication of surface relief gratings based on azo-chromophore, we have fabricated optical diffraction gratings with which the diffraction efficiency can be modulated by an electrochemical signal. Although patterned electroactive films have been made by many techniques, the copolymer approach employing the simple one-step surface relief gratings process displays optimal properties with respect to modulation depth and convenience, which avoids complicated electropolymerization steps or photochemical reactions. The electrochemically-induced modulation in the diffraction efficiency of the polyamide is believed to arise primarily from the effect of the redox state on the film's refractive index.
Co-reporter:Xiaofeng Lu, Xiujie Bian, Guangdi Nie, Chengcheng Zhang, Ce Wang and Yen Wei
Journal of Materials Chemistry A 2012 - vol. 22(Issue 25) pp:NaN12730-12730
Publication Date(Web):2012/05/24
DOI:10.1039/C2JM16559G
This work describes the encapsulation of conducting polypyrrole (PPy) into electrospun TiO2 nanofibers to form PPy/TiO2 nanocomposites using V2O5 as an oxidant and sacrificial template via a simple vapor phase polymerization approach. The PPy/TiO2 nanocomposites could be used as nanoreactors for loading Pd nanocatalysts towards the catalytic reduction of p-nitrophenol by sodium borohydride (NaBH4) at ambient conditions. The Pd nanocrystals synthesized through the in situ reduction by the PPy/TiO2 matrix have a small size of only about 2.0 nm. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible-near infrared spectroscopy (UV-vis-NIR) and thermo-gravimetric analysis (TGA) results demonstrated that PPy/TiO2 and PPy/TiO2/Pd composite nanofibers were successfully synthesized. Pd nanoparticles supported on the PPy/TiO2 composite nanofibers exhibited good catalytic activity when they worked as catalysts for the reduction of p-nitrophenol. The apparent kinetic rate constant (Kapp) was calculated to be about 12.2 × 10−3 s−1. The protective PPy/TiO2 composite nanofibers render the Pd nanoparticles stable against poisoning by the product of the reaction, enabling the composite nanocatalysts to be recyclable when used over multiple cycles.
Co-reporter:Danming Chao, Xiaoteng Jia, Fuquan Bai, Hongtao Liu, Lili Cui, Erik B. Berda and Ce Wang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 7) pp:NaN3034-3034
Publication Date(Web):2012/01/04
DOI:10.1039/C1JM13422A
We describe the synthesis of a novel poly(aryl ether), containing pendant oligoaniline and anthracene moieties (PAE-p-OA), and both side chains present in equal amounts. Structures were confirmed spectroscopically via nuclear magnetic resonance (NMR), morphological data ascertained viaX-ray diffraction (XRD), and thermal stability probed viathermogravimetric analysis (TGA). Electrochemical and photophysical properties were also investigated using cyclic voltammetry and UV-Vis and fluorescence spectroscopy. This material exhibits an interesting fluorescent response to redox active species. When PAE-p-OA is in the reduced state, oxidative materials interact with the oligoaniline side chains resulting in a progression from leucoemeraldine base (LEB) to the emeraldine base (EB). The resulting change in molecular conformation of the oliganiline unit increases its propensity for interaction with the anthracene side chain (corroborated by molecular modeling), leading to decreased fluorescence via quenching and thus “turn off” fluorescence sensing. When PAE-p-OA is in the oxidized state, reduction of the oligoaniline from the EB to the LEB via interaction with a reductive species delivers “turn on” fluorescence sensing via decreased interaction between the oligoaniline and anthracene side chains, again due to a change in the molecular conformation of oligoaniline.
Co-reporter:Guangdi Nie, Xiaofeng Lu, Junyu Lei, Ziqiao Jiang and Ce Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 37) pp:NaN15501-15501
Publication Date(Web):2014/06/19
DOI:10.1039/C4TA01732C
V2O5-doped α-Fe2O3 composite nanotubes have been successfully fabricated via a simple one-step electrospinning technique followed by calcination treatment. For the first time, we found that the magnetic properties of the as-prepared samples were significantly dependent on the contents of the dopant. In comparison with pristine α-Fe2O3, perfect reversibility, more excellent capacitance and better cycling stability were simultaneously observed for the hybrid metal oxide with an appropriate mass ratio of V2O5 (VFNT1) when it was utilized for supercapacitor electrodes, indicating that the doped α-Fe2O3 tubular nanostructures are fairly promising for practical applications not only in magnetic recording but also in the energy storage field.
Co-reporter:Rui Zhao, Xiang Li, Bolun Sun, Yanzi Li, Yumei Li, Rui Yang and Ce Wang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 3) pp:NaN1144-1144
Publication Date(Web):2016/12/01
DOI:10.1039/C6TA09784G
Cr(VI) is a well-known highly toxic metal ion and a thorough cleanup of this pollutant in wastewater is of special concern. Herein, a novel branched polyethylenimine (bPEI) grafted electrospun polyacrylonitrile (PAN) fiber membrane for Cr(VI) remediation based on adsorption was synthesized by a facile refluxing approach. Benefiting from the electrospinning process, the diameter of PAN fibers could be decreased to hundreds of nanometers from more than ten micrometers, which led to a higher adsorption capacity toward Cr(VI). In addition, the electrospun fibers showed good membrane forming properties, guaranteeing their application in the filtration purification process. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), elemental analysis, contact angle and so forth were used to characterize the grafted fiber membranes. Different grafting ratios were achieved by varying the refluxing time to search for the optimized removal capacity toward Cr(VI). The adsorption properties of the grafted fiber membrane including batch adsorption and filtration adsorption were investigated. The results revealed that the bPEI grafted electrospun PAN fiber adsorbent possessed an excellent adsorption capacity toward Cr(VI) (qm = 637.46 mg g−1), which was higher than many other adsorbents. Moreover, the batch adsorption and dynamic filtration could also make the Cr(VI) concentration notably decrease from 10 or 5 mg L−1 to below 0.05 mg L−1, which is recommended as the drinking water standard by WHO. The obtained results suggested that the grafted electrospun fiber membrane could be potentially applied to the efficient removal of Cr(VI) in wastewater treatment.
Co-reporter:Guangdi Nie, Xiaofeng Lu, Wei Wang, Maoqiang Chi, Yanzhou Jiang and Ce Wang
Inorganic Chemistry Frontiers 2017 - vol. 1(Issue 5) pp:NaN866-866
Publication Date(Web):2016/11/23
DOI:10.1039/C6QM00232C
A simple and green strategy was proposed for the first time to fabricate uniform polyaniline (PANi) thorn/BiOCl chip (BPB) heterostructures at a low temperature without the assistance of any surfactant. During the synthetic process, Bi2S3 nanowires acted as both the sacrificial template and the Bi source for BiOCl, affording the synchronous formation of HCl-doped PANi conductive arrays and BiOCl chips supported on residual Bi2S3 nanowires. As expected, when utilized as electrode materials for supercapacitors, the obtained BPB nanocomposite exhibited a better electrochemical performance in neutral media with enhanced specific capacitance, a more acceptable rate capability and a smaller charge-transfer resistance in comparison with the individual PANi nanofibers due to the unique hierarchical nanostructure of BPB and the synergistic effect between the ionizable BiOCl and the PANi chain.
Co-reporter:Libing He, Danming Chao, Xiaoteng Jia, Hongtao Liu, Lei Yao, Xincai Liu and Ce Wang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 6) pp:NaN1858-1858
Publication Date(Web):2010/12/03
DOI:10.1039/C0JM02960B
By an oxidative coupling polymerization approach, we have synthesized a novel electroactive polymer with good solubility containing alternating phenyl-capped aniline tetramer in the main chain and azo chromophores in the side chain. Dielectric properties of the as-synthesized polymer were investigated in detail and gratifying results have been observed. Firstly, a large enhancement in the dielectric constant was achieved utilizing the method of doping the conjugated oligoaniline segments with hydrochloric acid. Secondly, the adjustment of dielectric constant was implemented primarily by means of exposing the samples to UV and visible irradiation, mainly owing to the photoisomerization derived from azo chromophores in the side chain. The detailed characteristics of the as-synthesized polymer were systematically studied by Fourier-transform infrared (FTIR) spectra, nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). UV-vis spectra were used to monitor the photoisomerization and doping process of the polymer. The thermal characteristics of the polyamide were evaluated by thermogravimetric analysis (TGA). Moreover, the electrochemical activity of the polymer was explored by cyclic voltammogram (CV) measurement, showing that the intrinsic electroactivity of the oligoaniline was maintained in the polymer.
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