Co-reporter:Hui Feng, Niu Tang, Songbai Zhang, Bo Liu, Qingyun Cai
Journal of Colloid and Interface Science 2017 Volume 486() pp:58-66
Publication Date(Web):15 January 2017
DOI:10.1016/j.jcis.2016.09.048
A novel (CdS-Mn/MoS2/CdTe)-sensitized TiO2 nanotube arrays (NTAs) photoelectrode has been prepared by electrodeposite, successive ionic layer adsorption and reaction (SILAR) coupled with hydrothermal method. When a ZnS layer was added on the top of CdS-Mn/MoS2/CdTe/TiO2, a notable red-shift and high absorption was observed in the visible light region. The photocurrent density (mA/cm2) systematically increases from TiO2 NTAs (0.43), CdTe/TiO2 (1.09), MoS2/CdTe/TiO2 (1.80), CdS-Mn/MoS2/CdTe/TiO2 (2.40), to ZnS/CdS-Mn/MoS2/CdTe/TiO2 (3.41) under visible light irradiation, due to the type-II semiconductor heterostructures comprising multiple components with a staggered band offset. Such a heterostructure possesses an enhanced photocatalytic performance towards degradation of organic contaminant, e.g. P-Nitrophenol (PNP) and Rhodamine B (RhB).
Co-reporter:Bing Zhang;Xuehua Yin;Deshuai Zhen;Wenhong Gu;Yingju Liu
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 22) pp:13968-13973
Publication Date(Web):2017/11/06
DOI:10.1039/C7NJ02998E
A metal–semiconductor heterojunction material was synthesized by electrodepositing Au nanoparticles onto the surface of WO3 nanoflowers that were grown on TiO2 nanotubes and applied, for the first time, to the surface-enhanced Raman scattering (SERS) detection of dyes. Owing to their nanoflower structure, a localized surface plasmon resonance was generated on the surface of the Au/WO3/TiO2 nanosheets, which brings about multiple enhanced three-dimensional electromagnetic fields. An enhanced factor of 3.6 × 106 was achieved. The spot-to-spot change in the SERS intensity was less than 15% and the SERS substrate could be preserved for at least 50 days. The analysis of dyes in real samples provided a recovery rate of 94.33–115.6%, indicating its potential applications in environmental analysis.
Co-reporter:VanManh Nguyen, Weili Li, VanHuan Pham, Lijia Wang, Pengtao Sheng, Qingyun Cai, Craig Grimes
Journal of Colloid and Interface Science 2016 Volume 462() pp:389-396
Publication Date(Web):15 January 2016
DOI:10.1016/j.jcis.2015.10.005
•The novel CdS/ZnSe/TiO2 NTA photoelectrode is fabricated.•Highly visible light photocatalytic activities of CdS/ZnSe/TiO2 NTA were prepared.•Photocatalytic process with excellent stability was established.A novel CdS/ZnSe/TiO2 nanotube array (NTA) photoelectrode was prepared by deposition of ZnSe nanoparticles (NPs) using pulse electrodeposition technique onto a TiO2 NTA. By successive ion layer adsorption and reaction (SILAR), CdS quantum dots (QDs) deposit onto a ZnSe/TiO2 NTA photoelectrode. The as-prepared CdS/ZnSe/TiO2 NTA photoelectrode performance is significantly improved, which not only greatly extends spatial separation of charges, but also enhance the utilization efficiency of visible-light. This system exhibits excellent charges transport property. The maximum photocurrent density of an 8.25 mA cm−2 was observed in the CdS/ZnSe/TiO2 NTA photoelectrode, which is 37.5, 15.86 and 1.56 times higher than bare TiO2 NTA, ZnSe/TiO2 NTA, and CdS/TiO2NTA photoelectrodes, respectively. The photocatalytic activity of CdS/ZnSe/TiO2 NTA is tested by the degradation of methyl orange (MO) in distilled water under solar light irradiation of 100 mW/cm2. Within about 120 min of irradiation, 90.05% MO are removed.
Co-reporter:Ying Cai, Zhihong Yan, Lijia Wang, Manh NguyenVan, Qingyun Cai
Journal of Chromatography A 2016 Volume 1429() pp:97-106
Publication Date(Web):15 January 2016
DOI:10.1016/j.chroma.2015.12.032
•Magnetic solid phase extraction coupled with headspace sampling was used for sample pretreatment.•Cholesterol-functionalized MNPs were prepared as MSPE sorbents.•The extraction procedure was fast, simple and clean.•No organic solvent was used in the whole analytical procedure.A magnetic solid phase extraction (MSPE) protocol combining a static headspace gas chromatography coupled to mass spectrometry (HS-GC–MS) method has been developed for extraction, and determination of 16 polycyclic aromatic hydrocarbons (PAHs) in drinking water samples. Magnetic nanoparticles (MNPs) were coated with 3-aminopropyltriethoxysilane and modified by cholesterol chloroformate. Transmission electron microscope, vibrating sample magnetometer, Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy were used to characterize the cholesterol-functionalized sorbents, and the main parameters affecting the extraction as well as HS sampling, such as sorbent amount, extraction time, oven temperature and equilibration time have been investigated and established. Combination with HS sampling, the MSPE procedure was simple, fast and environmentally friendly, without need of any organic solvent. Method validation proved the feasibility of the developed sorbents for the quantitation of the investigated analytes at trace levels obtaining the limit of detection (S/N = 3) ranging from 0.20 to 7.8 ng/L. Good values for intra and inter-day precision were obtained (RSDs ≤ 9.9%). The proposed method was successfully applied to drinking water samples.
Co-reporter:VanManh Nguyen, Qingyun Cai, Craig A. Grimes
Journal of Colloid and Interface Science 2016 Volume 483() pp:287-294
Publication Date(Web):1 December 2016
DOI:10.1016/j.jcis.2016.08.042
•The novel CdS/Au/TiO2 NTA heterogeneous photoelectrode is fabricated.•Highly visible light photocatalytic activities of CdS/Au/TiO2 NTA were prepared.•The photocorrosion stability was established.A visible-light active photocatalyst, CdS/Au/TiO2 nanotube array (NTA) photoelectrode, was prepared by electrodeposition of Au nanoparticles onto TiO2 NTA with subsequent deposition of visible-light absorbable 2.4 eV band-gap CdS quantum dots using successive ion layer adsorption and reaction (SILAR). The Au nanoparticles here act as electron sinks facilitating charge carrier separation. Under AM1.5G illumination a photoconversion efficiency of 4.06% was achieved for the CdS/Au/TiO2 NTA photoelectrode, suggesting the promise of the material architecture for achieving high-performance cost-effective materials.
Co-reporter:Xuehua Yin, Pengtao Sheng, Fenfen Zhong, VanManh Nguyen, Qingyun Cai and Craig Grimes
New Journal of Chemistry 2016 vol. 40(Issue 8) pp:6675-6685
Publication Date(Web):24 May 2016
DOI:10.1039/C5NJ02894A
We describe the synthesis and application of a three-dimensional (3D) CdS quantum dot/ZnIn2S4 nanosheet/TiO2 nanotube array (CdS/ZnIn2S4/TiO2) heterostructured material architecture. TiO2 nanotube arrays (TiO2 NTAs) are used as the synthetic template, subsequently sensitized using hydrothermal and successive ion layer adsorption and reaction (SILAR) techniques. The described synthesis approach offers a powerful technique in the design of 3D heterostructure systems. Under AM1.5G illumination, the 3D CdS/ZnIn2S4/TiO2 samples generate a photocurrent of approximately 4.3 mA cm−2, with a photoconversion efficiency of 2%. Samples are tested for their ability to photocatalytically degrade target agents; it is noteworthy that after 90 min illumination 100% of 2,4-dichlorophenoxyacetic acid (2,4-D) is removed.
Co-reporter:Hai-Lan Lin, Zhi-Huang Li, Pei Liu, Bing-Bing Song, Qing-Yun Cai and Craig A. Grimes
Analytical Methods 2016 vol. 8(Issue 4) pp:912-918
Publication Date(Web):14 Dec 2015
DOI:10.1039/C5AY02540K
A wireless magnetoelastic-sensing device for the selective detection of benzo[a]pyrene (BaP) is reported using aminocalix[4]arene (AC4) monolayers as the sensor sensing elements and AC4-modified Au nanoparticles (AC4-Au NPs) as signal-amplifying tags. A sandwich-type detection strategy involves the AC4 self-assembled on the Au-protected sensor surface and AC4-Au NPs, both of which flank the BaP target in sequence. As the AC4-Au NPs combined BaP absorbs on the sensor's surface, there is an increase in the mass load on the sensor, and consequently a decrease in resonance frequency. Under optimal conditions, the sensor shows a linear response to the concentration of BaP in the range of 1.04 × 10−7 M to 1.04 × 10−11 M, with a detection limit of 5.0 × 10−11 M. Other polycyclic aromatic hydrocarbons (PAHs) and environmental pollutants show no interference on the detection.
Co-reporter:Pengtao Sheng, Weili Li, Pengwei Du, Kesheng Cao, Qingyun Cai
Talanta 2016 Volume 160() pp:537-546
Publication Date(Web):1 November 2016
DOI:10.1016/j.talanta.2016.07.043
•Single crystalline CuO nanowires were successfully immobilized on TiO2 nanotubes array.•Mass transport channel for Cu ions diffusion was confirmed.•Snow-like Ag nanocrystals modified CuO/TiO2 photoelectrodes exhibit superior catalytic and SERS properties.Vertically aligned single crystalline CuO nanowire arrays (NWs) grown directly on TiO2 nanotube arrays (NTAs) supporting by Ti foil have been successfully fabricated using facile thermal oxidation of Cu nanocrystals in static air. CuO NWs growth behavior dependent on parent Cu nanocrystals sizes has been well investigated. Mass transport channel of Cu ions in horizontal and vertical for supporting CuO NWs diameter and length changes has been confirmed through a novel step-by-step surface diffusion process. CuO NWs, nano-mushrooms and nanosheets can be easily obtained by varying growth conditions. After photocatalytic synthesis of snow-like Ag nanocrystals upon CuO NWs/TiO2 NTAs, the hybrid photoelectrode exhibits superior catalytic property and detection sensitivity, which can clean themselves by photocatalytic degradation of RhB molecules adsorbed to the substrate under irradiation using surface enhanced Raman scattering (SERS) detection, a recycling can been achieved.The growth process of CuO nanowires by thermal oxidation of deposition Cu nanocrystals on TiO2 NTAs in air.
Co-reporter:Na Bin, Weili Li, Xuehua Yin, Xiaohua Huang, Qingyun Cai
Talanta 2016 Volume 160() pp:570-576
Publication Date(Web):1 November 2016
DOI:10.1016/j.talanta.2016.07.046
•An cyt c ECL aptasensor was designed based on TiO2/CdS:Mn hybrids.•CdS:Mn QDs worked as the ECL emitter and aptamer linker.•The sensitivity was highly enhanced with using CdS:Mn QDs.•High specificity was achieved.•A wide linear range was achieved from 50 fM to 125 pM.A novel electrochemiluminescence (ECL) aptasensor was proposed for ultrasensitive detection of cytochrome c (cyt c) using CdS:Mn quantum dot-modified TiO2 nanowires (NWs) as electrode. The Mn-doped CdS was deposited on the TiO2 NWs by successive ion layer adsorption and reaction (SILAR) as ECL emitter, on which thiol-modified aptamer of cyt c was attached via Cd–S bond. Due to the high photo-electrical transfer efficiency, the as-prepared aptasensor shows high selectivity and sensitivity towards cyt c with a detection limit of 9.5 fM and a linear range from 50 fM to 125 pM.A novel electrochemiluminescence (ECL) aptasensor was proposed for ultrasensitive detection of cytochrome c (cyt c) using CdS:Mn quantum dot-modified TiO2 nanowires (NWs) as electrode. The Mn-doped CdS was deposited on the TiO2 NWs by successive ion layer adsorption and reaction (SILAR) as ECL emitter, on which thiol-modified aptamer of cyt c was attached via Cd–S bond. Due to the high photo-electrical transfer efficiency, the as-prepared aptasensor shows high selectivity and sensitivity towards cyt c with a detection limit of 9.5 fM and a linear range from 50 fM to 125 pM.
Co-reporter:Quan Zhou, Zeming Wu, Xiaohua Huang, Fenfen Zhong and Qingyun Cai
Analyst 2015 vol. 140(Issue 19) pp:6720-6726
Publication Date(Web):03 Aug 2015
DOI:10.1039/C5AN00452G
In this paper, a simple fluorescent probe, rhodamine B derivatives (RS), was designed and prepared for sensitive detection of Hg2+ in CH3CN/H2O (5/5, v/v). RS exhibits high selectivity and sensitivity toward Hg2+ over other common metal ions, displaying a significant color change from colorless to pink in the presence of Hg2+. The fluorescence responses remain stable over a broad pH range (5.0 to 9.0) and are suitable for detection under physiological conditions. Experimental results of HeLa cells and zebrafish show that RS is cell and organism permeable. We also demonstrate the acquisition of images of Hg2+ in HeLa cells and zebrafish by using a simple fluorescence confocal imaging technique.
Co-reporter:Zeming Wu, Xi Tong, Pengtao Sheng, Weili Li, Xuehua Yin, Jianmei Zou, Qingyun Cai
Applied Surface Science 2015 Volume 351() pp:309-315
Publication Date(Web):1 October 2015
DOI:10.1016/j.apsusc.2015.05.147
Highlights
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CuInSe2 nanocrystals with high photocatalytic activity were synthesized and immobilized onto TiO2 nanotube arrays.
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The highly photocatalytic activity of CuInSe2/TiO2 photoelectrode was evaluated in the hydrogen generation and photocatalytic degradation of 2,4-D and 9-AnCOOH.
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The CuInSe2/TiO2 photoelectrode possesses high photoelectrical efficiency and stability over the reported ones.
Co-reporter:Ying Cai, Zhi-Hong Yan, Ni-Ya Wang, Qing-Yun Cai and Shou-Zhuo Yao
RSC Advances 2015 vol. 5(Issue 69) pp:56189-56197
Publication Date(Web):18 Jun 2015
DOI:10.1039/C5RA10054B
A novel core–shell structured magnetic sorbent, naphthyl functionalized magnetic nanoparticles (Fe3O4@SiO2@Nap), was prepared and successfully applied for the magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) from river water samples. The analytes were finally determined by high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD). Seven kinds of PAHs were selected as the model analytes, including fluorene (Flu), fluoranthene (Fla), anthracene (Ant), pyrene (Pyr), benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF) and benzo[k]fluoranthene (BkF). Transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Fourier transform infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the sorbent. The main influencing parameters including sorbent amount, desorption solvent, sample volume and extraction time were optimized to achieve the highest recovery rate. Under the optimal conditions, only 40 mg of the Fe3O4@SiO2@Nap sorbent was used to extract the PAHs. The linear ranges of all the seven PAHs were 0.5–100 ng L−1 with the limits of detection (S/N = 3) ranging from 0.04 to 0.12 ng L−1. The repeatability was investigated by evaluating the intra- and inter-day precisions with relative standard deviations (RSDs) lower than 4.3%. Finally, the proposed method was successfully applied for the determination of PAHs in river water samples with recoveries in the range of 89.6–106.8%.
Co-reporter:Manh Nguyen Van, Weili Li, Pengtao Sheng, Huan Pham Van, Qingyun Cai
Journal of Electroanalytical Chemistry 2015 Volume 736() pp:69-75
Publication Date(Web):1 January 2015
DOI:10.1016/j.jelechem.2014.10.033
•A novel heterogeneous CdSe/CdS/Pt/TiO2 NTA were prepared and characterized.•The CdSe/CdS/Pt/TiO2 NTA photoelectrode was used for OCS PEC immunoassay.•The proposed immunosensor owns high sensitivity, specificity for OCS assay in sewage sample.A novel heterogeneous CdSe/CdS/Pt/TiO2 nanotube array photoelectrode (denoted as CdSe/CdS/Pt/TiO2 NTA) was developed by dipping and deposition technique as well as successive ionic layer adsorption and reaction (SILAR). An octachlorostyrene (OCS) photoelectrochemical immunosensor was constructed by cross-linking anti-OCS antibody onto the CdSe/CdS/Pt/TiO2 NTA using anti-OCS antibody prepared in this laboratory. The as-prepared photoelectrochemical immunosensor is highly stable, sensitive and selective to octachlorostyrene with a limit of detection (LOD) of 2.08 pM and a linear range from 0.1 to 10 μM. The practical application of the photoelectrochemical immunosensor is also realized in the selective determination of octachlorostyrene in sewage sample.
Co-reporter:Xuehua Yin, Jin Cai, Hongyan Feng, Zeming Wu, Jianmei Zou and Qingyun Cai
New Journal of Chemistry 2015 vol. 39(Issue 3) pp:1892-1898
Publication Date(Web):17 Dec 2014
DOI:10.1039/C4NJ01971G
A novel ultrasensitive sensing system for rapid fluorescence detection of cytochrome c (cyt c) was proposed by combining aptamer-based bioassay with VS2 nanosheets. VS2 nanosheets with high fluorescence quenching ability were synthesized by the solution route. A cyt c-binding aptamer was tagged with the fluorescent dye carboxy fluorescein (FAM), acting as the probe. VS2 nanosheets can adsorb the probe and quench its fluorescence efficiently. However, the fluorescence of the probe was retained when it was incubated with cyt c and then mixed with VS2 nanosheet solution. The proposed sensing system shows high selectivity and sensitivity, giving a linear range of 0.75 nM to 50 μM, and a limit of detection of 0.50 nM.
Co-reporter:Pengtao Sheng, Weili Li, Xi Tong, Xin Wang and Qingyun Cai
Journal of Materials Chemistry A 2014 vol. 2(Issue 44) pp:18974-18987
Publication Date(Web):13 Aug 2014
DOI:10.1039/C4TA02672A
Hollow chalcopyrite CuInSe2 nanospheres are prepared by colloidal synthesis, for the first time, and assembled inside TiO2 nanotube arrays (NTAs) as a high performance photocatalyst for hydrogen evolution. In order to improve the charge separation, we engineer the CuInSe2-based photoelectrode with a novel strategy: thin layer ZnS (pre-treatment), hollow CuInSe2 nanocrystals, Mn-doped CdS, and thin layer ZnS (post-treatment) are assembled onto TiO2 NTAs in sequence. The Mn–CdS shell, closely packed around the earlier-modified CuInSe2 nanocrystals, provides high surface coverage to passivate surface states and enhance light absorption intensity. Double ZnS layers as a quasi-quantum well yield much longer electron diffusion length favoring a high photoresponse. Cyclic voltammetry (CV) is used to confirm the stepwise conduction band edge and electrochemically active surface areas. A type II-like core/shell heterojunction model is proposed to elucidate the charge transfer mechanism. Electrochemical impedance spectroscopy (EIS) and open-circuit dark–light–dark photovoltage response support a two-channel charge transport mechanism in this type of photoelectrode. Photoluminescence (PL) spectroscopy indicates a dramatically reduced electron transfer from TiO2 NTAs to the sensitizer. The saturated short circle photocurrent achieved by the quantum well structure photoelectrode under illumination of AM 1.5 (100 mW cm−2) is 22.4 mA cm−2. The corresponding measured hydrogen evolution rate is 7.93 ml cm−2 h−1.
Co-reporter:Weili Li, Pengtao Sheng, Hongyan Feng, Xuehua Yin, Xuewei Zhu, Xu Yang, and Qingyun Cai
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 15) pp:12353
Publication Date(Web):July 10, 2014
DOI:10.1021/am502151m
A novel photoelectrode based on ZnS/CdTe/Mn-CdS/ZnS-sensitized three-dimensional macroporous ZnO nanosheet (NS) has been prepared by electrodeposition and successive ion layer adsorption and reaction (SILAR) method. The photoelectrode performances were significantly improved through the coupling of the core/shell CdTe/Mn-CdS quantum dots (QDs) with ZnO NS, and the introduction of the ZnS layer as a potential barrier. The photocurrent density systematically increases from ZnO NS (0.45 mA/cm2), CdTe/Mn-CdS/ZnO NS (4.98 mA/cm2), to ZnS/CdTe/Mn-CdS/ZnS/ZnO (6.23 mA/cm2) under the irradiation of AM 1.5G simulated sunlight. More important, the ZnS/CdTe/Mn-CdS/ZnS-sensitized ZnO NS photoelectrode provides a remarkable photoelectrochemical cell efficiency of 4.20% at −0.39 V vs Ag/AgCl.Keywords: macroporous ZnO nanosheet; photocatalytic degradation; photoelectrochemical; quantum dots; SILAR
Co-reporter:Chunyan Chen, Xiaotong Liang, Jianping Wang, Ying Zou, Huiping Hu, Qingyun Cai, Shouzhuo Yao
Journal of Chromatography A 2014 Volume 1348() pp:80-86
Publication Date(Web):27 June 2014
DOI:10.1016/j.chroma.2014.04.098
•A polymeric ionic liquid coating was covalently bonded to anodized Ti wire surface.•A cage-type polyhedral oligomeric silsesquioxane (POSS) was used as cross-linker.•The SPME fiber was used to extract perfluorinated compounds in direct immersion mode.•The SPME fiber was applied in environmental water samples.A novel solid-phase microextraction (SPME) fiber was developed by chemical binding of a crosslinked polymeric ionic liquid (PIL) on the surface of an anodized Ti wire, and was applied in direct-immersion mode for the extraction of perfluorinated compounds (PFCs) from water samples coupled with high performance liquid chromatography–tandem mass spectrometry analysis. The PIL coatings were synthesized by using 1-vinyl-3-hexylimidazolium hexafluorophosphate as monomer and methylacryloyl-substituted polyhedral oligomeric silsesquioxane (POSS) as cross-linker via free radical reaction. The proposed fiber coating exhibited high mechanical stability due to the chemical bonding between the coating and the Ti wire surface. The integration of POSS reagent enhanced the organic solvent resistance of the coating. The parameters affecting the extraction performance of the fiber coating including extraction time, pH of solution, ionic strength and desorption conditions were optimized. The developed PIL-POSS fiber showed good linearity (R < 0.998) between 0.1 and 50 ng mL−1 with method detection limits ranging from 0.005 to 0.08 ng mL−1 depending on the analyte, and with relative standard deviation for single-fiber repeatability and fiber-to-fiber reproducibility less than 8.6% and 9.5%, respectively.
Co-reporter:Quan Zhou, Yong Zhu, Pengtao Sheng, Zeming Wu and Qingyun Cai
RSC Advances 2014 vol. 4(Issue 87) pp:46951-46954
Publication Date(Web):29 Aug 2014
DOI:10.1039/C4RA03916E
A new spiropyran functionalized rhodamine derivative RB-SP2 has been synthesized and applied to detect Cu2+ and S2−. RB-SP2 was then used as an imaging probe for detection of these ions in HeLa cells at the physiological pH.
Co-reporter:Lei Shi, Hongyan Feng, Pingjing Zhang, Liping Zhou, Dexun Xie, Delie An, Qingyun Cai
Analytical Biochemistry 2014 Volume 447() pp:15-22
Publication Date(Web):15 February 2014
DOI:10.1016/j.ab.2013.11.004
Abstract
A competitive indirect enzyme-linked immunosorbent assay (ciELISA) was developed for detection of tris(2,3-dibromopropyl) isocyanurate (TBC). Polyclonal antibodies against TBC were raised from synthesized haptens and then screened against various coating antigens. After optimization of the immunoassay conditions, the linear range and IC50 value of the assay were 0.30–100 and 5.17 μg/L, respectively, with little cross-reactivity (⩽2%). Recovery of various samples (water, serum, soil) was tested and the values ranged from 68% to 110%. This ciELISA was also applied to determine TBC in the riverside soil of the Liuyang River, and the results were compared with the data obtained by UHPLC–MS/MS. The experimental assay results confirmed that this proposed immunoassay is a specific, sensitive, and reliable method for determination and monitoring of TBC.
Co-reporter:Hongyan Feng, Liping Zhou, Lei Shi, Weili Li, Lijuan Yuan, Daqing Li, Qingyun Cai
Analytical Biochemistry 2014 Volume 447() pp:49-54
Publication Date(Web):15 February 2014
DOI:10.1016/j.ab.2013.10.030
Co-reporter:Lan Chen, Jiezhen Li, T.Tran ThanhThuy, Liping Zhou, Chen'an Huang, Lijuan Yuan, Qingyun Cai
Biosensors and Bioelectronics 2014 Volume 52() pp:427-432
Publication Date(Web):15 February 2014
DOI:10.1016/j.bios.2013.08.026
•It is the first time to use the magnetoelastic sensor immunoassay method to test octachlorostyrene.•AuNPs here was used to amplify responses, increasing the sensitivity.•The limit of detection (LOD) of this proposal is 1.6 nM and the linear range is from 7.4 μM to 9 nM.A wireless, remote query octachlorostyrene (OCS) biosensor was fabricated by coating a mass-sensitive magnetoelastic ribbon with anti-OCS antibody. In response to a time-varying magnetic field, the magnetoelastic sensor mechanically vibrates at a characteristic resonance frequency which inversely depends on the sensor mass loading. As the magnetoelastic film is magnetostrictive itself, the vibrations launch magnetic flux that can be remotely detected using a pickup coil. Au nanoparticles (NPs) were used to amplify the mass loading. In a sample solution containing OCS target and OCS-modified AuNPs (OCS–AuNPs), both OCS and OCS–AuNPs react with the anti-OCS antibody immobilized on the sensor surface in a competition mode. The bound OCS–AuNPs amount is inversely proportional to the OCS target concentration. The reduction of bound OCS–AuNPs induced by free OCS results in significant change in mass loading, which amplifies the responses. The biosensor demonstrates a linear shift in resonance frequency with OCS concentration between 7.4 μM and 9 nM, with a detection limit of 2.8 nM.
Co-reporter:Hongyan Feng, Xi Tong, Weili Li, Liping Zhou, Lei Shi, Qingyun Cai
Talanta 2014 Volume 128() pp:434-444
Publication Date(Web):1 October 2014
DOI:10.1016/j.talanta.2014.04.059
•A highly specific monoclonal antibody against tris-(2,3-dibromopropyl) isocyanurate (TBC) was produced.•An indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) was developed based on the monoclonal antibody.•Specificity and sensitivity of the monoclonal antibody were on average higher than that of the polyclonal antibody.•The proposed IC-ELISA is a reliable, simple and cost effective system for rapid monitoring of TBC.Tris-(2,3-dibromopropyl) isocyanurate (TBC) is a heterocyclic brominated flame retardant and posses typical characteristic of Persistent Organic Pollutants (POPs). To meet the need for rapid and reliable monitoring of TBC, a monoclonal antibody was produced and an indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) was developed based on the monoclonal antibody. Monoclonal antibody against TBC was generated using synthesized haptens in mice. After optimization of the immunoassay conditions, results showed that the IC50 and the limit of detection (LOD) were 1.59 and 0.06 µg/L, respectively. The monoclonal antibody shows high specificity and the developed IC-ELISA is with high recoveries. The precision investigation indicated that the intra-assay precision values were all below 9.2% and that the inter-assay precision values ranged from 6.7 to 11.3%. The assay of real samples gives results basically consistent with UHPLC–MS/MS. The obtained results showed that this proposed immunoassay is a potential method for rapid and reliable monitoring of TBC.
Co-reporter:Hui Feng, Niya Wang, ThanhThuy Tran.T, Lijuan Yuan, Jiezhen Li, Qingyun Cai
Sensors and Actuators B: Chemical 2014 195() pp: 266-273
Publication Date(Web):
DOI:10.1016/j.snb.2014.01.036
Co-reporter:Xi Tong, Pengtao Sheng, Zhihong Yan, ThanhThuy Tran.T, Xin Wang, Jin Cai, Qingyun Cai
Sensors and Actuators B: Chemical 2014 198() pp: 41-48
Publication Date(Web):
DOI:10.1016/j.snb.2014.03.013
Co-reporter:Dr. Pengtao Sheng;Dr. Weili Li;Xin Wang;Xi Tong ;Dr. Qingyun Cai
ChemPlusChem 2014 Volume 79( Issue 12) pp:1785-1793
Publication Date(Web):
DOI:10.1002/cplu.201402161
Abstract
Morphology evolution dependence on reaction time has been investigated to find a way to overcome polydispersity of the chalcopyrite CuInSe2 nanocrystals (NCs). A building–crumbling process is presented to understand the formation of small NCs. By carefully controlling magnetic stirring, ligand content, and duration, the polydispersity is fundamentally improved; thus solid and hollow spherical NCs and quantum dots can be easily obtained with tunable sizes. It is proposed that the NCs undergo Ostwald ripening induced morphology evolution from solid to hollow NCs. The photoelectric properties and photocatalytic activity have been investigated with TiO2 nanotube array based photoelectrodes. A maximum saturation photocurrent of 12.6 mA cm−2 has been achieved, and a structure-dependent photocatalytic property has also been confirmed by using methyl orange as a model pollutant.
Co-reporter:Xin Wang, Pengtao Sheng, Liping Zhou, Xi Tong, Lei Shi, Qingyun Cai
Biosensors and Bioelectronics 2014 60() pp: 52-56
Publication Date(Web):
DOI:10.1016/j.bios.2014.03.056
Co-reporter:Pengtao Sheng, Weili Li, Jin Cai, Xin Wang, Xi Tong, Qingyun Cai and Craig A. Grimes
Journal of Materials Chemistry A 2013 vol. 1(Issue 26) pp:7806-7815
Publication Date(Web):30 Apr 2013
DOI:10.1039/C3TA10255F
Type-II core/shell CdTe/CdS quantum dots (QDs) are assembled onto TiO2 nanotube array (NTA) films using a bi-functional linker molecule with the help of a hydrothermal method coupled with successive ionic layer adsorption and reaction process. Spatial separation of the electron and hole wave functions within the core/shell heterostructured nanocrystals appears to result in an extended charge separation state, resulting in a significant increase in photocurrent and excellent device stability. When only CdS or CdTe QDs are used as the sensitizer, the largest photocurrent densities are 1.31 mA cm−2 and 1.23 mA cm−2, respectively. For the core/shell CdTe/CdS QDs sensitized TiO2 NTA photoelectrodes the photocurrent density increases to ≈9.17 mA cm−2, dramatically larger than the values obtained with only one sensitizer. The core/shell CdTe/CdS QDs sensitized TiO2 NTA photoelectrodes provide a remarkable photoelectrochemical cell efficiency of 6.12%. To the best of our knowledge this photoconversion efficiency is the highest in the field of QD-sensitized photoelectrodes. A corresponding hydrogen evolution rate as high as 1560 μmol h−1 W−1 was achieved.
Co-reporter:Chunyan Chen, Xiaotong Liang, Jianping Wang, Shaolei Yang, Zhihong Yan, Qingyun Cai, Shouzhuo Yao
Analytica Chimica Acta 2013 Volume 792() pp:45-51
Publication Date(Web):20 August 2013
DOI:10.1016/j.aca.2013.07.018
•A POSS reagent was used as cross-linker for the preparation of hybrid polymeric coating.•The organic–inorganic crosslinked structure greatly improved the robustness of SPME fiber.•An anodized Ti wire was functionalized and used as the fiber support.•The developed fiber was successfully applied to analysis of PAHs in environmental samples.A novel solid-phase microextraction (SPME) fiber was prepared by polymerization of an organic–inorganic hybrid polymeric coating on an anodized and derived Ti wire, and applied for the analysis of polycyclic aromatic hydrocarbons from environmental samples followed by high performance liquid chromatography (HPLC) analysis. A polyhedral oligomeric silsesquioxane (POSS) reagent containing methacryl substituent groups was used as an organic–inorganic hybrid cross-linker, and copolymerized with methyl methacrylate (MMA) to fabricate the hybrid coating via thermally initiated free radical polymerization in a glass capillary mold. The prepared fiber can be easily withdrawn from the glass capillary mold by controlling the polymerization conditions, especially polymerization solvent. A homogeneous and porous coating with thickness of about 100 μm was achieved using ethanol as polymerization solvent at the mass ratio of MMA to POSS as 1:0.5. High chemical and mechanical stability, as well as excellent durability for more than 100 times extractions with almost undiminished extraction efficiency were achieved due to the chemical immobilization and crosslinked hybrid coating. The proposed fiber showed much better extraction performance than the 100 μm commercial polydimethylsiloxane fiber for extracting PAHs from aqueous sample. The developed SPME-HPLC method for the determination of PAHs using the MMA–POSS hybrid coating achieved good linearity with good correlation coefficients (R = 0.991–0.999) and low detection limits in the range of 0.006 to 0.05 ng mL−1 (S/N = 3). The proposed fiber was successfully applied to the extraction of PAHs from environmental water samples with recoveries of 82–104% for river water, 83–103% for pool water, and 79–98% for wastewater, respectively.
Co-reporter:Hui Feng, Liping Zhou, Jiezhen Li, ThanhThuy Tran.T, Niya Wang, Lijuan Yuan, Zhihong Yan and Qingyun Cai
Analyst 2013 vol. 138(Issue 19) pp:5726-5733
Publication Date(Web):02 Jul 2013
DOI:10.1039/C3AN00956D
In this paper, tris(2,3-dibromopropyl) isocyanurate (TBC) is for the first time as far as we know determined by ultrasensitive photoelectrochemical (PEC) immunoassay using an antibody-modified ternary hybrid CdTe/Au–TiO2 nanotube arrays (NTAs) photoelectrode, developed by the pulse electrodeposition technique. The as-prepared hybrid shows enhanced photon absorption and photocurrent response, which subsequently increased the photoelectrical conversion efficiency in the visible region. TBC-antibody (Ab) was developed in rabbits as a result of immunization with the BSA–TBC conjugate and covalently cross-linked onto the CdTe/Au–TiO2 NTAs. Since the photocurrent is highly dependent on the TiO2 surface properties, the specific interaction between TBC and the antibody results in a sensitive change in the photocurrent, which displayed a linear range of 5.0 × 10−11 to 5.0 × 10−5 M and a low detection limit of 5.0 × 10−11 M for TBC determination. This proposed strategy highlights the application of TiO2 nanotube in visible-light-activated photoelectrochemical biosensing, which could largely reduce the destructive effect of UV light on biomolecules.
Co-reporter:Jiezhen Li, Niya Wang, ThanhThuy Tran.T, Chen'an Huang, Lan Chen, Lijuan Yuan, Liping Zhou, Rui Shen and Qingyun Cai
Analyst 2013 vol. 138(Issue 7) pp:2038-2043
Publication Date(Web):11 Jan 2013
DOI:10.1039/C3AN36653G
Pentachlorophenol (PCP) is an environmental pollutant of serious concern due to its high toxicity and long persistence property. Fast and sensitive detection of PCP is therefore of great interest. In this work, carbon quantum dots (QDs) are synthesized by hydrothermal reaction, and characterized by fluorescence spectrophotometer, fourier transform infrared (FT-IR) spectroscopy, UV/vis/NIR spectrophotometer and scanning electron microscopy (SEM). The carbon QDs show stable and intensive electrogenerated chemiluminescence (ECL) in the presence of the coreactant S2O82−. Under the scanning potential of −1.2 to 0.5 V, PCP reacts with the excited C˙−, resulting in a decrease in ECL. The detection of trace level PCP is therefore achieved using the carbon QDs and Pt working electrode. Parameters that may affect the ECL intensity including the pH of solution, ionic strength, concentrations of coreactant and carbon QDs are optimized. Under the optimal conditions, a detection limit of 1.3 × 10−12 g L−1 is achieved with a linear range of 10 pg L−1∼1.0 μg L−1.
Co-reporter:Chunyan Chen, Shaolei Yang, Di Pan, Yiming Long, Zhihong Yan, Qingyun Cai and Shouzhuo Yao
Analyst 2013 vol. 138(Issue 2) pp:569-575
Publication Date(Web):09 Nov 2012
DOI:10.1039/C2AN36315A
An octadecyl-functionalized solid-phase microextraction (SPME) fiber was prepared by sol–gel technology with an anodized Ti wire as the substrate and dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (C18-TMS) and tetraethoxysilane (TEOS) as sol–gel precursors. The anodized Ti wire has high mechanical strength and has numerous titanol groups on its surface for sol–gel reactions, consequently offering better performances than the commercial fragile fused silica substrate. The C18-TMS/TEOS sol–gel coated fiber has good thermal stability and stability against organic solvents. There is no loss in the performance after 100 cycles of exposure to acetonitrile and high temperature (300 °C) in turn. The developed fiber with a very thin (ca. 2 μm) coating thickness exhibits comparable or even superior extraction capability relative to the commercial 100 μm polydimethylsiloxane (PDMS) fiber. Under optimized conditions, the detection limits for the polycyclic aromatic hydrocarbons are in the range of 0.003 to 0.025 μg L−1 with a linear range from 0.01 to 20 μg L−1. The proposed method was successfully applied in the analysis of environmental water samples with the recoveries ranging from 85.3 to 101.8%.
Co-reporter:Jiezhen Li, Lan Chen, Chen'an Huang, Liping Zhou, Lijuan Yuan, Lei Shi, Dan Li and Qingyun Cai
Analyst 2013 vol. 138(Issue 22) pp:7023-7030
Publication Date(Web):02 Sep 2013
DOI:10.1039/C3AN01421E
Anti-octachlorostyrene (OCS) antibody was derived from an immune rabbit preparation. An OCS immunosensor was constructed by immobilizing the anti-OCS antibody on a glassy carbon electrode coated with chitosan and gold nanoparticles (AuNPs, ∼5 nm, represented as AuNP05). Large-sized AuNPs (∼90 nm, represented as AuNP90) were used as the electrochemical label. The AuNP90-labeled OCS competes with the target OCS for the limited antibody molecules immobilized on the sensor surface. The amount of bound AuNP90 is inversely proportional to the OCS concentration. OCS was quantified based on the bound AuNP90 which was detected by differential pulse voltammetry (DPV), i.e. the AuNP90 was firstly electrooxidized in 0.1 M HCl to produce AuCl4−, then the reduction current of AuCl4− was detected. The immobilized AuNP05 increases the loading of anti-OCS antibody. Both the immobilized AuNP05 and the label AuNP90 amplify the sensor response. The proposed electrochemical immunosensor exhibits high selectivity, good storage stability, and high sensitivity with a linear range from 1 to 500 nM (R2 = 0.971) and a detection limit of 0.4 nM.
Co-reporter:Shaolei Yang;Chunyan Chen;Zhihong Yan;Shouzhuo Yao
Journal of Separation Science 2013 Volume 36( Issue 7) pp:1283-1290
Publication Date(Web):
DOI:10.1002/jssc.201200983
Metal-organic frameworks, a new class of materials with high surface area and great porosity, have been widely applied in gas sorption. It is generally known that metal-organic framework 5 cannot be applied in aqueous phase since it is water sensitive. However, this work reveals that the derived material of metal-organic framework 5 is a good SPE sorbent that can be applied to aqueous phases. Metal-organic framework 5 was prepared and used as a SPE sorbent for the determination of polycyclic aromatic hydrocarbons in environmental matrices coupling with HPLC. The water treatment induced changes in the properties were investigated in detail. Even though metal-organic framework 5 is conversed to a second phase after water treatment, it still shows high extraction ability. Under the optimized experimental conditions, good sensitivity levels were achieved with low LODs ranging from 0.4 to 4.0 ng L−1 and a linearity of 0.004–20 μg L−1 (R2 > 0.996) for the investigated polycyclic aromatic hydrocarbons. The method has been validated in the analysis of real water samples with recoveries in the range of 80.2–120.2% and RSDs in the range of 0.5–11.7%.
Co-reporter:Lan Chen, ThanhThuy Tran. T, Chen’an Huang, Jiezhen Li, Lijuan Yuan, Qingyun Cai
Applied Surface Science 2013 Volume 273() pp:82-88
Publication Date(Web):15 May 2013
DOI:10.1016/j.apsusc.2013.01.184
Abstract
Here it is demonstrated that the Au–Ag-ZnO architecture can be immobilized on indium tin oxide (ITO) substrate through a facile three-step synthesis approach. A series of ZnO films with different modifications of Au and Ag were applied to study the effect of Ag and Au nanoparticles on the morphology, optical properties and photocatalytic activity. An annealing treatment of the ZnO nanosheets before Ag–Au deposition is found to play an important role in the properties of the Au–Ag-deposited ZnO nanosheet (Au–Ag-ZnO). The annealing treatment results in a significant increase in the surface area of ZnO, and consequently an increase in the depositing amount of Ag nanoparticles. The Au–Ag-ZnO film shows nearly twice the photocatalytic efficiency than pure ZnO, and much higher efficiency comparing with the Ag-ZnO film in the photocatalytic degradation of methyl orange (MO) under UV illumination in aqueous solutions.
Co-reporter:Qiong Su;Zi-Jian Zhao;Feng Xu;Peng-Cai Lou;Kai Zhang;De-Xun Xie;Lei Shi;Qing-Yun Cai;Zhi-Hong Peng ;De-Lie An
European Journal of Organic Chemistry 2013 Volume 2013( Issue 8) pp:1551-1557
Publication Date(Web):
DOI:10.1002/ejoc.201201422
Abstract
An efficient preparation for arylethynyl sulfides 1 and bis(arylethynyl) sulfides 2 has been accomplished through a one-pot, three-step strategy that starts from arylethanonyl sulfides and bis(arylethanonyl) sulfides, respectively, without the use of various terminal arylacetylenes as substrates. When lithium hexamethyldisilazane (LHMDS), ClP(O)(OEt)2, and LHMDS were sequentially added to a tetrahydrofuran solution of different substrates [arylethanonyl sulfides or bis(arylethanonyl) sulfides], 1 or 2 were obtained in moderate to good yields. The reaction procedure involves the formation of an enol phosphate and a subsequent base-induced elimination.
Co-reporter:Chunyan Chen, Jianping Wang, Shaolei Yang, Zhihong Yan, Qingyun Cai, Shouzhuo Yao
Talanta 2013 Volume 114() pp:11-16
Publication Date(Web):30 September 2013
DOI:10.1016/j.talanta.2013.04.018
•Preparation of a new mixed-mode coating based solid-phase microextraction fiber.•An anodized Ti wire with TiO2 nanotubes structure was employed as fiber substrate.•The new fiber was successfully applied in the analysis of environmental samples.A novel mixed-mode coating-based solid-phase microextraction (SPME) fiber was prepared by chemical bonding dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride and 3-(trimethoxysilyl)-1-propanamine, the sol–gel precursors, on an anodized Ti wire, aiming to effectively adsorb perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). The anodized Ti wire with uniform TiO2 nanotube arrays provides high mechanical strength and strong adhesion to the mixed-mode coating. The prepared fiber shows excellent organic solvent stability due to the covalent bonding between the coating and the fiber, and significantly higher extraction efficiency than the commercial fibers, 100 μm polydimethylsiloxane and 85 μm polyacrylate fiber, due to the synergistic extraction effects of the coating functional groups. Good linearity (R2=0.9994 for PFOS, R2=0.9992 for PFOA) was obtained with detection limits of 2.5 and 7.5 pg mL−1 for PFOS and PFOA, respectively. Recoveries were in the range of 88%–102%. The proposed method was successfully applied in the analysis of PFOS and PFOA in a local river with the results of 0.05 and 0.06 ng mL−1, respectively.
Co-reporter:Di Pan, Jianping Wang, Chunyan Chen, Chen'an Huang, Qingyun Cai, Shouzhuo Yao
Talanta 2013 Volume 108() pp:117-122
Publication Date(Web):15 April 2013
DOI:10.1016/j.talanta.2013.02.066
In this work, ultrasonic assisted extraction combined with solid phase extraction (SPE) was applied in the analysis of polycyclic aromatic hydrocarbons (PAHs) in environment samples. A titania nanotubes/titanium plate was modified with n-octadecanethiol monolayer-protected Ag nanoparticles, and developed as the adsorbent in SPE of PAHs. Six different PAHs in soil samples were analyzed with high performance liquid chromatography-fluorescence detection. The experiment conditions including the deposition time of Ag nanoparticles, extraction solvent properties, the amount of extraction solvent, the amount of organic modifier, extraction time, and desorption solvent properties were optimized. Under the optimized conditions, good linearity and low limits of detection of 0.0015–0.4 ng g−1 were obtained. The analysis of PAHs in real soil samples gave satisfactory recoveries ranging from 70.32% to 115.51% with 3.14%–13.56% intra-day relative standard deviations (RSD) and 4.92%–14.87% inter-day RSD.Highlights► UAE and SPE were used in sequence for the extraction of PAHs in soil samples. ► A TiO2 NTs/Ti modified with C18-Ag NPs was developed. ► The newly developed material was used as the adsorbent in SPE of PAHs. ► Six different PAHs in soil samples were analyzed with HPLC-FLD.
Co-reporter:Lei Shi, Liping Zhou, Guangkun Dai, Niya Wang, Delie An, Qingyun Cai
Talanta 2013 Volume 115() pp:386-393
Publication Date(Web):15 October 2013
DOI:10.1016/j.talanta.2013.05.026
•Several new haptens of Octachlorostyrene were synthesized for first time.•The haptens has succeeded in eliciting high-affinity antibodies against OCS.•The proposed ELISA showed great sensitivity and selectivity.•The ELISA without complex pretreatments was applied to water and sera samples and achieved better result than the GC method.A sensitive, competitive indirect enzyme-linked immunosorbent assay (ELISA) was developed for the detection of octachlorostyrene (OCS), a persistent and bioaccumulative toxicant. To achieve the most sensitive antibody, several haptens with different linkers that simulated the special structure of OCS were synthesized and conjugated to carrier proteins. Polyclonal rabbit antibodies against different immunizing antigens were obtained and screened against different coating antigens. Under the optimized conditions, this indirect ELISA shows a linear detection range from 1.4 to 86.3 ng/mL, with an IC50 value of 4.46 ng/mL and a limit of detections (LOD) of 0.1 ng/mL. Twelve kinds of compounds were tested for calculating cross-reactivities, and almost all of them showed little cross-reactivity (<5%). Water and sera samples spiked with OCS were analyzed by ELISA and the achieved recoveries were satisfied with a mean recovery of 92%. This immunoassay can be used as a rapid and convenient tool to monitoring OCS in environmental samples.Figure optionsDownload full-size imageDownload as PowerPoint slide
Co-reporter:Yiming Long, Yingzhuang Chen, Fei Yang, Chunyan Chen, Di Pan, Qingyun Cai and Shouzhuo Yao
Analyst 2012 vol. 137(Issue 11) pp:2716-2722
Publication Date(Web):27 Mar 2012
DOI:10.1039/C2AN16248B
Triphenylamine (TPA)-functionalized magnetic microspheres (Fe3O4/SiO2/TPA) were prepared and applied as solid phase extraction (SPE) adsorbents for the analysis of polycyclic aromatic hydrocarbons (PAHs) in environmental samples in combination with high-performance liquid chromatography (HPLC). The magnetic solid-phase extraction (MSPE) conditions affecting the extraction efficiency were optimized, including elution solvent, standing time, amount of sorbent, and salt concentration. Due to the strong π–π conjugate effect between the benzene rings of TPA and PAHs, high extraction efficiency was achieved with spiked recoveries of 80.21–108.33% and relative standard deviations (RSD) of less than 10%. Good linearities (R2 > 0.997) for all calibration curves were obtained with low limits of detection (LOD) of 0.25, 0.5, 0.5, 3.75, 0.2 and 0.04 ng L−1 for anthracene, fluoranthene, pyrene, chrysene, benzo[b]fluoranthene and benzo[k]fluoranthene, respectively. The achieved results indicate the applicability of Fe3O4/SiO2/TPA as MSPE adsorbents.
Co-reporter:Pengtao Sheng, Shangyuan Wu, Le Bao, Xin Wang, Zhang Chen and Qingyun Cai
New Journal of Chemistry 2012 vol. 36(Issue 12) pp:2501-2505
Publication Date(Web):18 Sep 2012
DOI:10.1039/C2NJ40604G
A metal-semiconductor heterojunction material was fabricated by photocatalytically depositing Au nanoparticles (NPs) inside titania nanotubes, and have been applied, for the first time, to the surface enhanced Raman (SER) scattering detection of polycyclic aromatic hydrocarbons (PAHs). Due to the nanotubular structure of the Au-NPs/TiO2 nanotubes (NTs), a localized surface plasmon resonance is generated within the Au-NPs/TiO2 NTs, which results in an enhanced three-dimensional electromagnetic field. Raman enhancement occurs when the PAH molecules are spatially confined within the zone of the Au-NPs/TiO2 NTs. The achieved detection limit of 12.6 nM, by utilizing a low-cost small Raman spectrometer, is comparable to the published values obtained with surface enhanced Raman scattering. The recovery rates measured with different water samples range from 89.97% to 116.2%.
Co-reporter:Sahar Sadat Mahshid, Sara Mahshid, Abolghasem Dolati, Mohammad Ghorbani, Lixia Yang, Shenglian Luo, Qingyun Cai
Electrochimica Acta 2011 Volume 58() pp:551-555
Publication Date(Web):30 December 2011
DOI:10.1016/j.electacta.2011.09.083
An electro-catalysis non-enzymatic electrode is proposed based on alloyed Pt/Ni nanowire arrays (NWAs) for the detection of glucose. The Pt/Ni NWAs were prepared by pulse electrodeposition of Pt and Ni within a nano-pore polycarbonate (PC) membrane followed by a chemical etching of the membrane. The electrode structure is characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The resulting Pt/Ni NWAs electrode shows high electrocatalytic activities towards the oxidation of glucose in alkaline solution. Consequently, a sensitive amperometric detection of glucose is achieved under 0.45 V vs. SCE with a low detection limit of 1.5 μM within a wide linear range from 2 μM to 2 mM (R = 0.997). Furthermore, the oxidable species such as ascorbic acid and uric acid show no significant interference in determination of glucose. Finally, the experiment results reveal a very good reproducibility and high stability for the proposed Pt/Ni NWAs electrode.
Co-reporter:Pengtao Sheng, Weili Li, Jin Cai, Xin Wang, Xi Tong, Qingyun Cai and Craig A. Grimes
Journal of Materials Chemistry A 2013 - vol. 1(Issue 26) pp:NaN7815-7815
Publication Date(Web):2013/04/30
DOI:10.1039/C3TA10255F
Type-II core/shell CdTe/CdS quantum dots (QDs) are assembled onto TiO2 nanotube array (NTA) films using a bi-functional linker molecule with the help of a hydrothermal method coupled with successive ionic layer adsorption and reaction process. Spatial separation of the electron and hole wave functions within the core/shell heterostructured nanocrystals appears to result in an extended charge separation state, resulting in a significant increase in photocurrent and excellent device stability. When only CdS or CdTe QDs are used as the sensitizer, the largest photocurrent densities are 1.31 mA cm−2 and 1.23 mA cm−2, respectively. For the core/shell CdTe/CdS QDs sensitized TiO2 NTA photoelectrodes the photocurrent density increases to ≈9.17 mA cm−2, dramatically larger than the values obtained with only one sensitizer. The core/shell CdTe/CdS QDs sensitized TiO2 NTA photoelectrodes provide a remarkable photoelectrochemical cell efficiency of 6.12%. To the best of our knowledge this photoconversion efficiency is the highest in the field of QD-sensitized photoelectrodes. A corresponding hydrogen evolution rate as high as 1560 μmol h−1 W−1 was achieved.
Co-reporter:Pengtao Sheng, Weili Li, Xi Tong, Xin Wang and Qingyun Cai
Journal of Materials Chemistry A 2014 - vol. 2(Issue 44) pp:NaN18987-18987
Publication Date(Web):2014/08/13
DOI:10.1039/C4TA02672A
Hollow chalcopyrite CuInSe2 nanospheres are prepared by colloidal synthesis, for the first time, and assembled inside TiO2 nanotube arrays (NTAs) as a high performance photocatalyst for hydrogen evolution. In order to improve the charge separation, we engineer the CuInSe2-based photoelectrode with a novel strategy: thin layer ZnS (pre-treatment), hollow CuInSe2 nanocrystals, Mn-doped CdS, and thin layer ZnS (post-treatment) are assembled onto TiO2 NTAs in sequence. The Mn–CdS shell, closely packed around the earlier-modified CuInSe2 nanocrystals, provides high surface coverage to passivate surface states and enhance light absorption intensity. Double ZnS layers as a quasi-quantum well yield much longer electron diffusion length favoring a high photoresponse. Cyclic voltammetry (CV) is used to confirm the stepwise conduction band edge and electrochemically active surface areas. A type II-like core/shell heterojunction model is proposed to elucidate the charge transfer mechanism. Electrochemical impedance spectroscopy (EIS) and open-circuit dark–light–dark photovoltage response support a two-channel charge transport mechanism in this type of photoelectrode. Photoluminescence (PL) spectroscopy indicates a dramatically reduced electron transfer from TiO2 NTAs to the sensitizer. The saturated short circle photocurrent achieved by the quantum well structure photoelectrode under illumination of AM 1.5 (100 mW cm−2) is 22.4 mA cm−2. The corresponding measured hydrogen evolution rate is 7.93 ml cm−2 h−1.
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