Two-dimensional van der Waals electrical contact to monolayer MoSi2N4
作者：
Cao, Liemao;Zhou, Guanghui;Wang, Qianqian;Ang, L. K.* ;Ang, Yee Sin*
期刊：
Applied Physics Letters ,2021年118(1):013106 ISSN：0003-6951
通讯作者：
Ang, L. K.;Ang, Yee Sin
作者机构：
[Cao, Liemao] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.;[Wang, Qianqian; Cao, Liemao; Ang, L. K.; Ang, Yee Sin] Singapore Univ Technol & Design SUTD, Sci Math & Technol SMT, 8 Somapah Rd, Singapore 487372, Singapore.;[Zhou, Guanghui] Hunan Normal Univ, Dept Phys, Changsha 410081, Peoples R China.
通讯机构：
[Ang, LK; Ang, YS] S;Singapore Univ Technol & Design SUTD, Sci Math & Technol SMT, 8 Somapah Rd, Singapore 487372, Singapore.
摘要：
A two-dimensional (2D) MoSi2N4 monolayer is an emerging class of air-stable 2D semiconductors possessing exceptional electrical and mechanical properties. Despite intensive recent research effort devoted to uncover the material properties of MoSi2N4, the physics of electrical contacts to MoSi2N4 remains largely unexplored thus far. In this work, we study van der Waals heterostructures composed of MoSi2N4 contacted by graphene and NbS2 monolayers using first-principles density functional theory calculations. We show that the MoSi2N4/NbS2 contact exhibits an ultralow Schottky barrier height (SBH), which is beneficial for nanoelectronics applications. For the MoSi2N4/graphene contact, the SBH can be modulated via the interlayer distance or via external electric fields, thus opening up an opportunity for reconfigurable and tunable nanoelectronic devices. Our findings provide insights into the physics of 2D electrical contacts to MoSi2N4 and shall offer a critical first step toward the design of high-performance electrical contacts to MoSi2N4-based 2D nanodevices.
语种：
英文
展开
Rapid recognition and determination of tryptophan by carbon nanotubes and molecularly imprinted polymer-modified glassy carbon electrode
作者：
Wu, Yiyong;Deng, Peihong* ;Tian, Yaling;Ding, Ziyu;Li, Guangli;...
期刊：
Bioelectrochemistry ,2020年131:107393 ISSN：1567-5394
通讯作者：
He, Quanguo;Deng, Peihong
作者机构：
[Li, Guangli; He, Quanguo; Tian, Yaling; Zuberi, Zavuga; Ding, Ziyu; Wu, Yiyong; Liu, Jun] Hunan Univ Technol, Sch Life Sci & Chem, Zhuzhou 412007, Peoples R China.;[He, Quanguo; Tian, Yaling; Ding, Ziyu; Deng, Peihong; Wu, Yiyong; Liu, Jun] Hengyang Normal Univ, Key Lab Funct Organometall Mat Hunan Prov Univ, Dept Chem & Mat Sci, Key Lab Funct Met Organ Cpds Hunan Prov, Hengyang 421008, Peoples R China.;[Zuberi, Zavuga] Nelson Mandela African Inst Sci & Technol, Sch Life Sci & Bioengn, POB 447, Arusha, Tanzania.;[Deng, Peihong] Hengyang Normal Univ, Hengyang 421008, Peoples R China.
通讯机构：
[He, Quanguo; Deng, Peihong] H;Hunan Univ Technol, Sch Life Sci & Chem, Zhuzhou 412007, Peoples R China.;Hengyang Normal Univ, Hengyang 421008, Peoples R China.
关键词：
Molecularly imprinting;Multi-walled carbon nanotubes;Tryptophan;Voltammetric sensor
摘要：
A tryptophan (Trp) molecularly imprinted electrochemical sensor was fabricated by drop-coating an imprinted chitosan film on the surface of a glassy carbon electrode modified with multi-walled carbon nanotubes (MIP-MWCNTs/GCE). The surface morphology and electrochemical properties of the MIP-MWCNTs/GCE were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV), respectively. The formation of hydrogen bonds between the functional polymer and the template molecule was confirmed by infrared spectroscopy. The electrochemical performance of the MIP-MWCNTs/GCE with Trp showed that the signal of the oxidation current of Trp obtained with MIP-MWCNTs/GCE was significantly enhanced relative to that of the uncovered GCE, indicating that the modified electrode can accelerate electron transfer and has strong selectivity for Trp. The experimental conditions were optimized in parallel, and under the optimal conditions, the MIP-MWCNTs/GCE showed a good linear relationship between the Trp oxidation peak current and Trp concentrations in the ranges of 2.0 nM–0.2 μM, 0.2 μM–10 μM and 10 μM–100 μM The limit of detection (LOD) was 1.0 nM (S/N = 3), and the modified electrode had good reproducibility and stability. Finally, the MIP-MWCNTs/GCE was successfully applied to the determination of Trp in the human serum samples. © 2019
语种：
英文
展开
Injection of oxygen vacancies in the bulk lattice of layered cathodes
作者：
Yan, Pengfei* ;Zheng, Jianming;Tang, Zhen-Kun;Devaraj, Arun;Chen, Guoying;...
期刊：
Nature Nanotechnology ,2019年14(6):602-608 ISSN：1748-3387
通讯作者：
Yan, Pengfei;Wang, Chongmin;Liu, Li-Min
作者机构：
[Devaraj, Arun; Yan, Pengfei; Wang, Chongmin] Pacific Northwest Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA.;[Yan, Pengfei] Beijing Univ Technol, Inst Microstruct & Properties Adv Mat, Beijing Key Lab Microstruct & Properties Solids, Beijing, Peoples R China.;[Zheng, Jianming; Zhang, Ji-Guang] Pacific Northwest Natl Lab, Energy & Environm Directorate, Richland, WA 99352 USA.;[Tang, Zhen-Kun] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang, Peoples R China.;[Tang, Zhen-Kun; Liu, Li-Min] Beihang Univ, Sch Phys, Beijing, Peoples R China.
通讯机构：
[Yan, PF; Wang, CM] P;[Yan, Pengfei; Liu, Li-Min] B;Pacific Northwest Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA.;Beijing Univ Technol, Inst Microstruct & Properties Adv Mat, Beijing Key Lab Microstruct & Properties Solids, Beijing, Peoples R China.;Beihang Univ, Sch Phys, Beijing, Peoples R China.
摘要：
Surfaces, interfaces and grain boundaries are classically known to be sinks of defects generated within the bulk lattice. Here, we report an inverse case by which the defects generated at the particle surface are continuously pumped into the bulk lattice. We show that, during operation of a rechargeable battery, oxygen vacancies produced at the surfaces of lithium-rich layered cathode particles migrate towards the inside lattice. This process is associated with a high cutoff voltage at which an anionic redox process is activated. First-principle calculations reveal that triggering of this redox process leads to a sharp decrease of both the formation energy of oxygen vacancies and the migration barrier of oxidized oxide ions, therefore enabling the migration of oxygen vacancies into the bulk lattice of the cathode. This work unveils a coupled redox dynamic that needs to be taken into account when designing high-capacity layered cathode materials for high-voltage lithium-ion batteries. © 2019, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
语种：
英文
展开
A promising sensing platform toward dopamine using MnO2 nanowires/electro-reduced graphene oxide composites
作者：
He, Quanguo;Liu, Jun;Liu, Xiaopeng;Li, Guangli* ;Chen, Dongchu;...
期刊：
Electrochimica Acta ,2019年296:683-692 ISSN：0013-4686
通讯作者：
Deng, Peihong;Li, Guangli
作者机构：
[He, Quanguo; Li, Guangli; Liang, Jing; Liu, Xiaopeng; Liu, Jun] Hunan Univ Technol, Coll Life Sci & Chem, Hunan Key Lab Biomed Nanomat & Devices, Zhuzhou 412007, Peoples R China.;[Chen, Dongchu] Foshan Univ, Sch Mat Sci & Energy Engn, Foshan 528000, Peoples R China.;[Deng, Peihong] Hengyang Normal Univ, Dept Chem & Mat Sci, 165 Huangbai Rd, Yanfeng Dist 421008, Hengyang, Peoples R China.;[Li, Guangli] Hunan Univ Technol, Coll Life Sci & Chem, 88 West Taishan Rd, Tianyuan Dist 412007, Zhuzhou, Peoples R China.
通讯机构：
[Deng, Peihong; Li, Guangli] H;Hengyang Normal Univ, Dept Chem & Mat Sci, 165 Huangbai Rd, Yanfeng Dist 421008, Hengyang, Peoples R China.;Hunan Univ Technol, Coll Life Sci & Chem, 88 West Taishan Rd, Tianyuan Dist 412007, Zhuzhou, Peoples R China.
关键词：
MnO2 nanowires;Reduced graphene oxide;Modified electrode;Dopamine sensor;Electrocatalytic oxidation
摘要：
A promising sensing platform for the ultrasensitive detection of dopamine (DA) has been constructed using MnO2 nanowires-electrochemically reduced graphene oxide modified glassy carbon electrode (MnO2 NWs-ErGO/GCE). The proposed MnO2 NWs-ErGO/GCEs had the large electrochemical active area and relative low charge transfer resistant (R-ct). As a result, the response peak current of the MnO2 NWs-ErGO is about 13 times higher than that of the bare GCE, demonstrating the remarkable electrocatalytic activity toward DA. The electrochemical kinetics revealed that DA oxidation is quasi-reversible reaction coupling with one electron and two protons. Three linear ranges (0.01 mu M - 0.10 mu M, 0.10 mu M - 1.0 mu M, and 1.0 mu M - 80 mu M) were obtained on the MnO2 NWs-ErGO/GCE, with a low detection limit of 1.0 nM (S/N = 3). Moreover, the response current was almost unaltered even in the presence of 100-fold ascorbic acid (AA) and uric acid (UA), suggesting MnO2 NWs-ErGO has good selectivity toward DA. Finally, the MnO2 NWs-ErGO/GCEs were successfully applied to detect DA in the injection solutions and human blood serum samples with high accuracy and good recovery. (C) 2018 Elsevier Ltd. All rights reserved.
语种：
英文
展开
Interference-assisted kaleidoscopic meta-plexer for arbitrary spin-wavefront manipulation
作者：
Xu, He-Xiu* ;Hu, Guangwei;Li, Ying;Han, Lei;Zhao, Jianlin;...
期刊：
光：科学与应用 ,2019年8(1):3 ISSN：2095-5545
通讯作者：
Xu, He-Xiu;Qiu, Cheng-Wei;Cui, Tie Jun
作者机构：
[Han, Lei; Xu, He-Xiu; Hu, Guangwei; Qiu, Cheng-Wei; Li, Ying; Xu, HX] Natl Univ Singapore, Dept Elect & Comp Engn, Singapore 117583, Singapore.;[Xu, He-Xiu; Wang, Guang-Ming; Yuan, Fang] Air Force Engn Univ, Air & Missile Def Coll, Xian 710051, Shaanxi, Peoples R China.;[Xu, He-Xiu; Ling, Xiaohui] Hengyang Normal Univ, Coll Phys & Elect Engn, Hunan Prov Key Lab Intelligent Informat Proc & Ap, Hengyang 421008, Peoples R China.;[Han, Lei; Zhao, Jianlin] Northwestern Polytech Univ, Sch Nat & Appl Sci, Xian 710072, Shaanxi, Peoples R China.;[Sun, Yunming] Adv Tech Dept, Key Lab Aeronaut Comp Tech, Xian 710075, Shaanxi, Peoples R China.
通讯机构：
[Xu, HX; Qiu, CW] N;[Xu, He-Xiu] A;[Xu, He-Xiu] H;[Cui, Tie Jun] S;Natl Univ Singapore, Dept Elect & Comp Engn, Singapore 117583, Singapore.
摘要：
Achieving simultaneous polarization and wavefront control, especially circular polarization with the auxiliary degree of freedom of light and spin angular momentum, is of fundamental importance in many optical applications. Interferences are typically undesirable in highly integrated photonic circuits and metasurfaces. Here, we propose an interference-assisted metasurface-multiplexer (meta-plexer) that counterintuitively exploits constructive and destructive interferences between hybrid meta-atoms and realizes independent spin-selective wavefront manipulation. Such kaleidoscopic meta-plexers are experimentally demonstrated via two types of single-layer spin-wavefront multiplexers that are composed of spatially rotated anisotropic meta-atoms. One type generates a spin-selective Bessel-beam wavefront for spin-down light and a low scattering cross-section for stealth for spin-up light. The other type demonstrates versatile control of the vortex wavefront, which is also characterized by the orbital angular momentum of light, with frequency-switchable numbers of beams under linearly polarized wave excitation. Our findings offer a distinct interference-assisted concept for realizing advanced multifunctional photonics with arbitrary and independent spin-wavefront features. A variety of applications can be readily anticipated in optical diodes, isolators, and spin-Hall meta-devices without cascading bulky optical elements. © 2019, The Author(s).
语种：
英文
展开
Recent advances in the spin Hall effect of light
作者：
Ling, Xiaohui;Zhou, Xinxing;Huang, Kun;Liu, Yachao;Qiu, Cheng-Wei* ;...
期刊：
Reports on Progress in Physics ,2017年80(6):066401 ISSN：0034-4885
通讯作者：
Qiu, Cheng-Wei
作者机构：
[Ling, Xiaohui] Hengyang Normal Univ, Coll Phys & Elect Engn, Hunan Prov Key Lab Intelligent Informat Proc & Ap, Hengyang 421002, Peoples R China.;[Qiu, Cheng-Wei; Ling, Xiaohui] Natl Univ Singapore, Dept Elect & Comp Engn, 4 Engn Dr 3, Singapore 117576, Singapore.;[Wen, Shuangchun; Luo, Hailu; Ling, Xiaohui; Liu, Yachao] Hunan Univ, Sch Phys & Elect, Minist Educ, Lab Micro Nanooptoelect Devices, Changsha 410082, Hunan, Peoples R China.;[Zhou, Xinxing] Hunan Normal Univ, Coll Phys & Informat Sci, Synerget Innovat Ctr Quantum Effects & Applicat, Changsha 410081, Hunan, Peoples R China.;[Huang, Kun] Agcy Sci Technol & Res, Inst Mat Res & Engn, 2 Fusionopolis Way,Innovis 08-03, Singapore 138634, Singapore.
通讯机构：
[Qiu, Cheng-Wei] N;[Qiu, Cheng-Wei] S;Natl Univ Singapore, Dept Elect & Comp Engn, 4 Engn Dr 3, Singapore 117576, Singapore.;Shenzhen Univ, SZU NUS Collaborat Innovat Ctr Optoelect Sci & Te, Shenzhen 518060, Peoples R China.;NUS Suzhou Res Inst NUSRI, Suzhou Ind Pk, Suzhou 215123, Peoples R China.
关键词：
geometric phase;spin Hall effect of light;spin Hall shift;weak measurements
摘要：
The spin Hall effect (SHE) of light, as an analogue of the SHE in electronic systems, is a promising candidate for investigating the SHE in semiconductor spintronics/valleytronics, high-energy physics and condensed matter physics, owing to their similar topological nature in the spin-orbit interaction. The SHE of light exhibits unique potential for exploring the physical properties of nanostructures, such as determining the optical thickness, and the material properties of metallic and magnetic thin films and even atomically thin two-dimensional materials. More importantly, it opens a possible pathway for controlling the spin states of photons and developing next-generation photonic spin Hall devices as a fundamental constituent of the emerging spinoptics. In this review, based on the viewpoint of the geometric phase gradient, we give a detailed presentation of the recent advances in the SHE of light and its applications in precision metrology and future spin-based photonics. © 2017 IOP Publishing Ltd.
语种：
英文
展开
Visible-Frequency Metasurface for Structuring and Spatially Multiplexing Optical Vortices
作者：
Mehmood, M. Q.;Mei, Shengtao;Hussain, Sajid;Huang, Kun;Siew, S. Y.;...
期刊：
Advanced Materials ,2016年28(13):2533-2539 ISSN：0935-9648
通讯作者：
Qiu, Cheng-Wei
作者机构：
[Mei, Shengtao; Mehmood, M. Q.; Zhang, Tianhang; Ling, Xiaohui; Zhang, Lei; Qiu, Cheng-Wei; Hussain, Sajid; Danner, Aaron; Siew, S. Y.] Natl Univ Singapore, Dept Elect & Comp Engn, 4 Engn Dr 3, Singapore 117583, Singapore.;[Mei, Shengtao; Qiu, Cheng-Wei] Natl Univ Singapore, Ctr Life Sci CeLS, Grad Sch Integrat Sci & Engn, 05-01,28 Med Dr, Singapore 117456, Singapore.;[Liu, Hong; Huang, Kun; Teng, Jinghua] Innovis, A STAR, Inst Mat Res & Engn, 08-03,2 Fusionopolis Way, Singapore 138634, Singapore.;[Ling, Xiaohui] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.;[Zhang, Shuang] Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England.
通讯机构：
[Qiu, Cheng-Wei] N;Natl Univ Singapore, Dept Elect & Comp Engn, 4 Engn Dr 3, Singapore 117583, Singapore.;Natl Univ Singapore, Ctr Life Sci CeLS, Grad Sch Integrat Sci & Engn, 05-01,28 Med Dr, Singapore 117456, Singapore.
关键词：
babinet-inverted;metalens;multifocus;optical-vortex beam;topological charge
摘要：
A multifocus optical vortex metalens, with enhanced signal-to-noise ratio, is presented, which focuses three longitudinal vortices with distinct topological charges at different focal planes. The design largely extends the flexibility of tuning the number of vortices and their focal positions for circularly polarized light in a compact device, which provides the convenience for the nanomanipulation of optical vortices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
语种：
英文
展开
Bag of visual words and fusion methods for action recognition: Comprehensive study and good practice
作者：
Peng, Xiaojiang* ;Wang, Limin;Wang, Xingxing;Qiao, Yu
期刊：
Computer Vision and Image Understanding ,2016年150:109-125 ISSN：1077-3142
通讯作者：
Peng, Xiaojiang
作者机构：
[Peng, Xiaojiang] Hengyang Normal Univ, Coll Comp Sci & Technol, Hengyang, Peoples R China.;[Wang, Limin] Swiss Fed Inst Technol, Comp Vis Lab, Zurich, Switzerland.;[Wang, Xingxing; Qiao, Yu; Wang, Limin; Peng, Xiaojiang] Chinese Acad Sci, Shenzhen Inst Adv Technol, Shenzhen, Peoples R China.;[Peng, Xiaojiang] INRIA, LEAR Team, Grenoble, France.
通讯机构：
[Peng, Xiaojiang] H;[Peng, Xiaojiang] C;[Peng, Xiaojiang] I;Hengyang Normal Univ, Coll Comp Sci & Technol, Hengyang, Peoples R China.;Chinese Acad Sci, Shenzhen Inst Adv Technol, Shenzhen, Peoples R China.
关键词：
Action recognition;Bag of visual words;Feature encoding;Fusion methods
摘要：
Video based action recognition is one of the important and challenging problems in computer vision research. Bag of visual words model (BoVW) with local features has been very popular for a long time and obtained the state-of-the-art performance on several realistic datasets, such as the HMDB51, UCF50, and UCF101. BoVW is a general pipeline to construct a global representation from local features, which is mainly composed of five steps; (i) feature extraction, (ii) feature pre-processing, (iii) codebook generation, (iv) feature encoding, and (v) pooling and normalization. Although many efforts have been made in each step independently in different scenarios, their effects on action recognition are still unknown. Meanwhile, video data exhibits different views of visual patterns, such as static appearance and motion dynamics. Multiple descriptors are usually extracted to represent these different views. Fusing these descriptors is crucial for boosting the final performance of an action recognition system. This paper aims to provide a comprehensive study of all steps in BoVW and different fusion methods, and uncover some good practices to produce a state-of-the-art action recognition system. Specifically, we explore two kinds of local features, ten kinds of encoding methods, eight kinds of pooling and normalization strategies, and three kinds of fusion methods. We conclude that every step is crucial for contributing to the final recognition rate and improper choice in one of the steps may counteract the performance improvement of other steps. Furthermore, based on our comprehensive study, we propose a simple yet effective representation, called hybrid supervector, by exploring the complementarity of different BoVW frameworks with improved dense trajectories. Using this representation, we obtain impressive results on the three challenging datasets; HMDB51 (61.9%), UCF50 (92.3%), and UCF101 (87.9%). © 2016 Elsevier Inc.
语种：
英文
展开
Giant photonic spin Hall effect in momentum space in a structured metamaterial with spatially varying birefringence
作者：
Ling, Xiaohui;Zhou, Xinxing;Yi, Xunong;Shu, Weixing;Liu, Yachao;...
期刊：
光：科学与应用 ,2015年4(5):e290 ISSN：2095-5545
通讯作者：
Luo, Hailu
作者机构：
[Fan, Dianyuan; Shu, Weixing; Wen, Shuangchun; Luo, Hailu; Zhou, Xinxing; Ling, Xiaohui; Liu, Yachao; Chen, Shizhen] Hunan Univ, Sch Phys & Elect, Lab Spin Photon, Changsha 410082, Hunan, Peoples R China.;[Ling, Xiaohui] Hengyang Normal Univ, Dept Phys & Elect Informat Sci, Hengyang 421002, Peoples R China.;[Fan, Dianyuan; Yi, Xunong; Ling, Xiaohui] Shenzhen Univ, SZU NUS Collaborat Innovat Ctr Optoelect Sci & Te, Shenzhen 518060, Peoples R China.;[Fan, Dianyuan; Yi, Xunong; Ling, Xiaohui] Shenzhen Univ, Key Lab Optoelect Devices & Syst, Minist Educ & Guangdong Prov, Shenzhen 518060, Peoples R China.
通讯机构：
[Luo, Hailu] H;Hunan Univ, Sch Phys & Elect, Lab Spin Photon, Changsha 410082, Hunan, Peoples R China.
关键词：
geometric phase;metamaterial;photonic spin Hall effect
摘要：
The photonic spin Hall effect (SHE) in the reflection and refraction at an interface is very weak because of the weak spin-orbit interaction. Here, we report the observation of a giant photonic SHE in a dielectric-based metamaterial. The metamaterial is structured to create a coordinate-dependent, geometric Pancharatnam Berry phase that results in an SHE with a spin-dependent splitting in momentum space. It is unlike the SHE that occurs in real space in the reflection and refraction at an interface, which results from the momentum-dependent gradient of the geometric Rytov Vladimirskii Berry phase. We theorize a unified description of the photonic SHE based on the two types of geometric phase gradient, and we experimentally measure the giant spin-dependent shift of the beam centroid produced by the metamaterial at a visible wavelength. Our results suggest that the structured metamaterial offers a potential method of manipulating spin-polarized photons and the orbital angular momentum of light and thus enables applications in spin-controlled nanophotonics. © 2015 CIOMP.
语种：
英文
展开
A graphene oxide-based electrochemical sensor for sensitive determination of 4-nitrophenol
作者：
Li, Junhua* ;Kuang, Daizhi;Feng, Yonglan;Zhang, Fuxing;Xu, Zhifeng;...
期刊：
Journal of Hazardous Materials ,2012年201-202:250-259 ISSN：0304-3894
通讯作者：
Li, Junhua
作者机构：
[Liu, Mengqin; Xu, Zhifeng; Li, Junhua; Zhang, Fuxing; Feng, Yonglan; Kuang, Daizhi] Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Hunan, Peoples R China.;[Liu, Mengqin; Xu, Zhifeng; Li, Junhua; Zhang, Fuxing; Feng, Yonglan; Kuang, Daizhi] Hengyang Normal Univ, Hunan Prov College, Key Lab Funct Organometall Mat, Hengyang 421008, Hunan, Peoples R China.
通讯机构：
[Li, Junhua] H;Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Hunan, Peoples R China.
关键词：
4-Nitrophenol;Electrochemical sensor;Graphene oxide;Sensitive detection
摘要：
A graphene oxide (GO) film coated glassy carbon electrode (GCE) was fabricated for sensitive determination of 4-nitrophenol (4-NP). The GO-based sensor was characterized by scanning electron microscope, atomic force microscopy and electrochemical impedance spectroscopy. The electrochemical behaviors of 4-NP at the GO-film coated GCE were investigated in detail. In 0.1 M acetate buffer with a pH of 4.8, 4-NP yields a very sensitive and well-defined reduction peak at the GO-modified GCE. It is found that the GO film exhibits obvious electrocatalytic activity toward the reduction of 4-NP since it not only increases the reduction peak current but also lowers the reduction overpotential. Based on this, an electrochemical method was proposed for the direct determination of 4-NP. Various kinetic parameters such as transfer electron number, transfer proton number and standard heterogeneous rate constant were calculated, and various experimental parameters were also optimized. Under the optimal conditions, the reduction peak current varies linearly with the concentration of 4-NP ranging from 0.1 to 120 mu M, and the detection limit is 0.02 mu M at the signal noise ratio of 3. Moreover, the fabricated sensor presented high selectivity and long-term stability. This electrochemical sensor was further applied to determine 4-NP in real water samples, and it showed great promise for simple, sensitive, and quantitative detection of 4-NP. (C) 2011 Elsevier B.V. All rights reserved.
语种：
英文
展开
