Co-reporter:Zhouli Chen;Jingxin Zhao;Keke Huang;Xuxin Yang;Jichun You;Quanlin Ye;Changmin Hou;Yongjin Li
Industrial & Engineering Chemistry Research January 13, 2016 Volume 55(Issue 1) pp:80-85
Publication Date(Web):Publication Date (Web): December 14, 2015
DOI:10.1021/acs.iecr.5b03578
By coupling the self-assembly of polystyrene-block-poly(ethylene oxide)-containing titanium-tetraisopropoxide and tungsten hexaphenoxide (the precursors of TiO2 and WO3, respectively) with electrospinning technique, the hierarchically porous TiO2/WO3 composite nanofibers with inner-bicontinuous and outer-shell structures have been synthesized. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were employed to characterize the structure of the fibers. In these nanofibers, the TiO2 acts as the frames, and WO3 fills the gaps. The UV–vis spectroscopy suggests that the spectral response range has been successfully extended into the visible regime. Furthermore, the resulting fabrics show enhanced performance in the photocatalytic degradation of acetaldehyde relative to neat TiO2 and neat WO3. Our results indicate that electrospinning the blend solution of block copolymer and two kinds of precursor of inorganic material is an effective strategy to fabricate composite nanofibers that can improve the photocatalytic activity of TiO2, especially for visible light.
Co-reporter:Na Liu, Yanli Su, Zhiqiang Wang, Zhen Wang, Jinsong Xia, Yong Chen, Zhigang Zhao, Qingwen Li, and Fengxia Geng
ACS Nano August 22, 2017 Volume 11(Issue 8) pp:7879-7879
Publication Date(Web):July 18, 2017
DOI:10.1021/acsnano.7b02344
A three-dimensional (3D) macroscopic network of manganese oxide (MnO2) sheets was synthesized by an easily scalable solution approach, grafting the negatively charged surfaces of the MnO2 sheets with an aniline monomer by electrostatic interactions followed by a quick chemical oxidizing polymerization reaction. The obtained structure possessed MnO2 sheets interconnected with polyaniline chains, producing a 3D monolith rich in mesopores. The MnO2 sheets had almost all their reactive centers exposed on the electrode surface, and combined with the electron transport highways provided by polyaniline and the shortened diffusion paths provided by the porous structure, the deliberately designed electrode achieved an excellent capacitance of 762 F g–1 at a current of 1 A g–1 and cycling performance with a capacity retention of 90% over 8000 cycles. Furthermore, a flexible asymmetric supercapacitor based on the constructed electrode and activated carbon serving as the positive and negative electrodes, respectively, was successfully fabricated, delivering a maximum energy density of 40.2 Wh kg–1 (0.113 Wh cm–2) and power density of 6227.0 W kg–1 (17.44 W cm–2) in a potential window of 0–1.7 V in a PVA/Na2SO4 gel electrolyte.Keywords: 3D network; electrostatic interaction; flexible devices; manganese oxide; two-dimensional sheets;
Co-reporter:Zhen Wang;Qingzhu Zhang;Shan Cong;Zhigang Chen;Jinxiong Zhao;Mei Yang;Zuhui Zheng;Sha Zeng;Xuwen Yang;Fengxia Geng
Advanced Optical Materials 2017 Volume 5(Issue 11) pp:
Publication Date(Web):2017/06/01
DOI:10.1002/adom.201700194
Dual-band electrochromic composite materials are of utmost importance in advancing the electrochromic field toward achieving the ideal smart window with independent control over visible and near-infrared (NIR) radiation. However, such composites usually need deliberate architecting of their mesoscale structure (e.g., via block copolymer-templating method) to make the electrolyte contact with both NIR and visible-light modulating components. Herein, instead of arduously making exterior pores, the intrinsic structural tunnels are utilized directly in electrochromic materials to facilitate the accommodation and transportation of insertion ions, which permit the infiltration of the electrolyte to be in contact with both visible (Prussian blue) and NIR-light modulating components (nonstoichiometric tungsten oxide). Such simple-fabricated composite materials exhibit excellent dual-band electrochromic performance with an unprecedented dynamic optical range for modulation of visible and NIR light, up to 71.2% at 633 nm and 64.8% at 1600 nm, respectively.
Co-reporter:Zhigang Chen, Lianhui Li, Shan Cong, Jinnan Xuan, Dengsong Zhang, Fengxia Geng, Ting Zhang, and Zhigang Zhao
Nano Letters 2017 Volume 17(Issue 1) pp:
Publication Date(Web):December 7, 2016
DOI:10.1021/acs.nanolett.6b04272
A key challenge in current superhard materials research is the design of novel superhard nanocrystals (NCs) whereby new and unexpected properties may be predicted. Cubic boron nitride (c-BN) is a superhard material which ranks next to diamond; however, downsizing c-BN material below the 10 nm scale is rather challenging, and the interesting new properties of c-BN NCs remain unexplored and wide open. Herein we report an electrochemical shock method to prepare uniform c-BN NCs with a lateral size of only 3.4 ± 0.6 nm and a thickness of only 0.74 ± 0.3 nm at ambient temperature and pressure. The fabrication process is simple and fast, with c-BN NCs produced in just a few minutes. Most interestingly, the NCs exhibit excellent piezoelectric performance with a large recordable piezoelectric coefficient of 25.7 pC/N, which is almost 6 times larger than that from bulk c-BN and even competitive to conventional piezoelectric materials. The phenomenon of enhancement in the piezoelectric properties of BN NCs might arise from the nanoscale surface effect and nanoscale shape effect of BN NCs. This work paves an interesting route for exploring new properties of superhard NCs.Keywords: Cubic boron nitride; electrochemical shock; nanocrystals; piezoelectricity;
Co-reporter:Weikun Zhang, Chong Lin, Shan Cong, Junyu Hou, Bin Liu, Fengxia Geng, Jian Jin, Minghong Wu and Zhigang Zhao
RSC Advances 2016 vol. 6(Issue 18) pp:15234-15239
Publication Date(Web):29 Jan 2016
DOI:10.1039/C5RA27635G
Li–S batteries are regarded as one of the most promising energy-storage devices due to their high theoretical energy density, five times higher than that of lithium-ion batteries (2600 vs. ∼500 W h kg−1). However, the polysulfide shuttle effect is the primary challenge for future applications of Li–S batteries. Herein, a novel barrier layer material, nonstoichiometric W18O49 nanowires, is reported to alleviate the undesirable shuttle effect, thereby largely boosting the specific capacity and cyclability of Li–S batteries. Without particular cathode design, the introduction of W18O49 nanowires enables the commercially available micro-sized sulfur cathode with 70% sulfur loading to deliver a respectable initial discharge capacity of 1142 mA h g−1 and retain a specific capacity of about 809 mA h g−1 after 50 cycles, even at a current density of 0.5 A g−1. To the best of our knowledge, such a capacity fading for Li–S batteries based on high loading of commercial micro-sized sulfur has been rarely reported.
Co-reporter:Jinxiong Zhao;Yuyu Tian;Zhen Wang;Dr. Shan Cong; Di Zhou;Qingzhu Zhang;Mei Yang;Weikun Zhang; Fengxia Geng; Zhigang Zhao
Angewandte Chemie International Edition 2016 Volume 55( Issue 25) pp:7161-7165
Publication Date(Web):
DOI:10.1002/anie.201602657
Abstract
A recent technological trend in the field of electrochemical energy storage is to integrate energy storage and electrochromism functions in one smart device, which can establish efficient user–device interactions based on a friendly human-readable output. This type of newly born energy storage technology has drawn tremendous attention. However, there is still plenty of room for technological and material innovation, which would allow advancement of the research field. A prototype Al-tungsten oxide electrochromic battery with interactive color-changing behavior is reported. With the assistance of trace amount of H2O2, the battery exhibits a specific capacity almost seven times that for the reported electrochromic batteries, up to 429 mAh g−1. Fast decoloration of the reduced tungsten oxide affords a very quick charging time of only eight seconds, which possibly comes from an intricate combination of structure and valence state changes of tungsten oxide. This unique combination of features may further advance the development of smart energy storage devices with suitability for user–device interactions.
Co-reporter:Jinxiong Zhao;Yuyu Tian;Zhen Wang;Dr. Shan Cong; Di Zhou;Qingzhu Zhang;Mei Yang;Weikun Zhang; Fengxia Geng; Zhigang Zhao
Angewandte Chemie 2016 Volume 128( Issue 25) pp:7277-7281
Publication Date(Web):
DOI:10.1002/ange.201602657
Abstract
A recent technological trend in the field of electrochemical energy storage is to integrate energy storage and electrochromism functions in one smart device, which can establish efficient user–device interactions based on a friendly human-readable output. This type of newly born energy storage technology has drawn tremendous attention. However, there is still plenty of room for technological and material innovation, which would allow advancement of the research field. A prototype Al-tungsten oxide electrochromic battery with interactive color-changing behavior is reported. With the assistance of trace amount of H2O2, the battery exhibits a specific capacity almost seven times that for the reported electrochromic batteries, up to 429 mAh g−1. Fast decoloration of the reduced tungsten oxide affords a very quick charging time of only eight seconds, which possibly comes from an intricate combination of structure and valence state changes of tungsten oxide. This unique combination of features may further advance the development of smart energy storage devices with suitability for user–device interactions.
Co-reporter:Junyu Hou; Yuanchuan Zheng; Yanli Su; Weikun Zhang; Tatsumasa Hoshide; Feifei Xia; Jiansheng Jie; Qingwen Li; Zhigang Zhao; Renzhi Ma; Takayoshi Sasaki;Fengxia Geng
Journal of the American Chemical Society 2015 Volume 137(Issue 40) pp:13200-13208
Publication Date(Web):September 22, 2015
DOI:10.1021/jacs.5b09138
The strong interest in macroscopic graphene and/or carbon nanotube (CNT) fiber has highlighted that anisotropic nanostructured materials are ideal components for fabricating fiber assemblies. Prospectively, employing two-dimensional (2D) crystals or nanosheets of functionality-rich transition metal oxides would notably enrich the general knowledge for desirable fiber constructions and more importantly would greatly broaden the scope of functionalities. However, the fibers obtained up to now have been limited to carbon-related materials, while those made of 2D crystals of metal oxides have not been achieved, probably due to the intrinsically low mechanical stiffness of a molecular sheet of metal oxides, which is only few hundredths of that for graphene. Here, using 2D titania sheets as an illustrating example, we present the first successful fabrication of macroscopic fiber of metal oxides composed of highly aligned stacking sheets with enhanced sheet-to-sheet binding interactions. Regardless of the intrinsically weak Ti–O bond in molecular titania sheets, the optimal fiber manifested mechanical performance comparable to that documented for graphene or CNTs. This work provided important hints for devising optimized architecture in macroscopic assemblies, and the rich functionalities of titania promises fibers with limitless promise for a wealth of innovative applications.
Co-reporter:Yuyu Tian;Weikun Zhang;Shan Cong;Yuanchuan Zheng;Fengxia Geng
Advanced Functional Materials 2015 Volume 25( Issue 36) pp:5833-5839
Publication Date(Web):
DOI:10.1002/adfm.201502638
Electrochromic devices have many important commercial applications ranging from electronic paper like displays, antiglare rear-view mirrors in cars, to energy-saving smart windows in buildings. Monovalent ions such as H+, Li+, and Na+ are widely used as insertion ions in electrochromic devices but have serious limitations such as instability, high-cost, and hard handling. The utilization of trivalent ions as insertion ions has been largely overlooked probably because of the strong electrostatic interactions between ions and intercalation framework and the resulted difficulties of intercalation. It is demonstrated that the trivalent ion, Al3+, can be used as efficient insertion ion by using metal oxide hosts in nanostructured form, which brings the desired fast-switch, high-contrast, and high-stability as well to electrochromic devices. Differing from the usual structure degradation by repeated guest intercalation/deintercalation, the Al3+ insertion introduces strong electrostatic forces, which on some degree stabilize the crystal structure and consequently yield much enhanced performances.
Co-reporter:Shan Cong;Yuyu Tian;Qingwen Li;Fengxia Geng
Advanced Materials 2014 Volume 26( Issue 25) pp:4260-4267
Publication Date(Web):
DOI:10.1002/adma.201400447
Co-reporter:Yuyu Tian, Shan Cong, Wenming Su, Hongyuan Chen, Qingwen Li, Fengxia Geng, and Zhigang Zhao
Nano Letters 2014 Volume 14(Issue 4) pp:2150-2156
Publication Date(Web):March 4, 2014
DOI:10.1021/nl5004448
Supercapacitors are important energy storage technologies in fields such as fuel-efficient transport and renewable energy. State-of-the-art supercapacitors are capable of supplanting conventional batteries in real applications, and supercapacitors with novel features and functionalities have been sought for years. Herein, we report the realization of a new concept, a smart supercapacitor, which functions as a normal supercapacitor in energy storage and also communicates the level of stored energy through multiple-stage pattern indications integrated into the device. The metal-oxide W18O49 and polyaniline constitute the pattern and background, respectively. Both materials possess excellent electrochemical and electrochromic behaviors and operate in different potential windows, −0.5–0 V (W18O49) and 0–0.8 V (polyaniline). The intricate cooperation of the two materials enables the supercapacitor to work in a widened, 1.3 V window while displaying variations in color schemes depending on the level of energy storage. We believe that our success in integrating this new functionality into a supercapacitor may open the door to significant opportunities in the development of future supercapacitors with imaginative and humanization features.
Co-reporter:Jing Zhang, Hongyuan Chen, Hongbo Li, Jiangtao Di, Minghai Chen, Fengxia Geng, Zhigang Zhao, and Qingwen Li
Chemistry of Materials 2014 Volume 26(Issue 9) pp:2789
Publication Date(Web):April 23, 2014
DOI:10.1021/cm500606z
Noble metal catalysts are core materials for many energy conversion and storage technologies such as fuel cell and hydrogen storage, while the performances of the noble metals depend critically on the nature of support materials. Herein, for the first time, we report the use of sorted high-purity metallic (m-) and semiconducting (s-) single-walled carbon nanotubes (SWNTs) as support materials for a typical noble metal catalyst, Pd, which has been believed to have strong interactions with SWNTs. Our results clearly suggest that electrocatalytic performances of the noble metals/SWNTs hybrid system, specifically in hydrogen electrosorption and formic acid electrooxidation, exhibit strongly sensitive dependence with respect to the electronic type of SWNT supports. Pd nanoparticles on m-SWNTs demonstrate much enhanced electrocatalytic activities compared with those on s-SWNTs or unsorted-SWNTs. Our in-depth mechanism studies indicate that the m-SWNTs in the nanocomposite tend to provide more effective charge-transfer interfaces with Pd nanoparticles, more likely leading to higher electron densities on Pd nanoparticles to boost their catalytic performance. The present study provides a novel window onto the design and synthesis of new feasible electrocatalyst system for efficient energy conversion and storage.
Co-reporter:Rui Zhu, Shan Cong, Yuyu Tian, Hongbo Li, Minghai Chen, Yanlin Huang, Zhigang Zhao and Qingwen Li
Chemical Communications 2013 vol. 49(Issue 51) pp:5787-5789
Publication Date(Web):03 May 2013
DOI:10.1039/C3CC41779D
Nitrogen-doped tungstic acid hydrate (N-doped H2W1.5O5.5·H2O) has been developed as a new kind of efficient “three-in-one” water treatment material. The new material shows excellent uptake capacity towards various aqueous pollutants, as well as good photocatalytic detoxification and visible-light-driven photosensitized degradation performance.
Co-reporter:Jichun You, Wenjia Sheng, Keke Huang, Changmin Hou, Huijuan Yue, Bin Hu, Min Wang, Donglei Wei, Qingwen Li, Liping Zhao, Wenyong Dong, Zhigang Zhao, and Yongjin Li
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 6) pp:2278
Publication Date(Web):March 2, 2013
DOI:10.1021/am4003099
By coupling the self-assembly of polystyrene-block-poly(ethylene oxide) (PS-b-PEO) containing titanium precursors with the electrospinning technique, novel cigarlike nanofibers with an outer-shell and inner-continuous-pore structure and resultant fabrics were fabricated. Different from typical porous metal oxides, the prepared high-surface-area nonwoven fabrics show excellent mechanical properties. Not only are these fabrics self-supporting over a large area, but they can also be cut using scissors, which is important for large-scale applications. Furthermore, as electrode materials in Li-ion batteries, these fabrics exhibit much higher charge/discharge capacity and cycle stability compared with the commercially available nanosized TiO2 (P25). The improved mechanical and electrochemical performances are attributed to the presence of an outer-shell, inner-bicontinuous structures (including continuous TiO2 frame and continuous nanopores) and hierarchical pores from the cigarlike nanofibers.Keywords: block copolymer; cigarlike; electrospinning; hierarchical porous; TiO2;
Co-reporter:Zhi-Gang Zhao, Zhao-Jun Yao, Jing Zhang, Rui Zhu, Yu Jin and Qing-Wen Li
Journal of Materials Chemistry A 2012 vol. 22(Issue 32) pp:16514-16519
Publication Date(Web):25 Jun 2012
DOI:10.1039/C2JM32769D
Platinum/tungsten oxide (Pt/WO3) is a very important hybrid material system, which has been found to have wide applications from photochemistry to heterogeneous catalysis. For the first time, we combine electrospinning and galvanic replacement reaction as a new fabrication method for the in-situ anchoring of galvanically replaced Pt nanocubes and nanospheres onto the surface of electrospun WO3 nanofibers to yield a 1D heterostructure. This constructed nanostructure tied with carbon nanotubes as a novel nanostructured three-phase electrode for methanol oxidation exhibits exceptional catalytic activity. It is found that the morphology of both the Pt nanostructures and tungsten oxide support play an important role in the catalytic activity and stability for methanol oxidation. The peak current density of Pt nanocubes-anchored to WO3 nanofibers is about 4.5 times higher than that of their spherical counterparts under the same condition. The current decay with time for the Pt nanocubes/WO3 nanofibers is much slower than that for Pt nanocubes/commercial WO3. The novel multidimensional, multicomponent and multifunctional Pt/WO3 nanostructures offer a new material platform for solar cells, photocatalysis, fuel cells, sensors, and other applications. Such a hybrid design has been demonstrated to be an effective means for bridging functional nanoscale entities with a practical macroscale device.
Co-reporter:Zhaojun Yao, Jiangtao Di, Zhenzhong Yong, Zhigang Zhao and Qingwen Li
Chemical Communications 2012 vol. 48(Issue 66) pp:8252-8254
Publication Date(Web):29 Jun 2012
DOI:10.1039/C2CC32925E
We develop a simple dry wrapping method to fabricate a tungsten oxide (WO3)/carbon nanotube (CNT) cable, in which WO3 layers act as an electrochromic component while aligned CNTs as the core provide mechanical support and an anisotropic, continuous electron transport pathway. Interestingly, the resultant cable material exhibits an obvious gradient electrochromic phenomenon.
Co-reporter:Zhi-Gang Zhao, Zhao-Jun Yao, Jing Zhang, Rui Zhu, Yu Jin and Qing-Wen Li
Journal of Materials Chemistry A 2012 - vol. 22(Issue 32) pp:
Publication Date(Web):
DOI:10.1039/C2JM32769D
Co-reporter:Rui Zhu, Shan Cong, Yuyu Tian, Hongbo Li, Minghai Chen, Yanlin Huang, Zhigang Zhao and Qingwen Li
Chemical Communications 2013 - vol. 49(Issue 51) pp:NaN5789-5789
Publication Date(Web):2013/05/03
DOI:10.1039/C3CC41779D
Nitrogen-doped tungstic acid hydrate (N-doped H2W1.5O5.5·H2O) has been developed as a new kind of efficient “three-in-one” water treatment material. The new material shows excellent uptake capacity towards various aqueous pollutants, as well as good photocatalytic detoxification and visible-light-driven photosensitized degradation performance.
Co-reporter:Zhigang Chen, Zhengxu Tao, Shan Cong, Junyu Hou, Dengsong Zhang, Fengxia Geng and Zhigang Zhao
Chemical Communications 2016 - vol. 52(Issue 76) pp:NaN11445-11445
Publication Date(Web):2016/08/25
DOI:10.1039/C6CC06325J
A simple, general and fast method called “electrochemical shock” is developed to prepare monolayered transition-metal dichalcogenide (TMD) QDs with an average size of 2–4 nm and an average thickness of 0.85 ± 0.5 nm with only about 10 min of ultrasonication. Just like nails hammered into a plate, the electrochemical shock with Al3+ ions and the following extraction with the help of oleic acid can disintegrate bulk TMD crystals into ultrafine TMD QDs. The fast-prepared QDs are then applied to detect highly explosive molecules such as 2,4,6-trinitrophenol (TNP) with a low detection limit of 10−6 M. Our versatile method could be broadly applicable for the fast production of ultrathin QDs of other materials with great promise for various applications.
Co-reporter:Zhaojun Yao, Jiangtao Di, Zhenzhong Yong, Zhigang Zhao and Qingwen Li
Chemical Communications 2012 - vol. 48(Issue 66) pp:NaN8254-8254
Publication Date(Web):2012/06/29
DOI:10.1039/C2CC32925E
We develop a simple dry wrapping method to fabricate a tungsten oxide (WO3)/carbon nanotube (CNT) cable, in which WO3 layers act as an electrochromic component while aligned CNTs as the core provide mechanical support and an anisotropic, continuous electron transport pathway. Interestingly, the resultant cable material exhibits an obvious gradient electrochromic phenomenon.
