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1.
《Surface and interface analysis : SIA》2005,37(12):1092-1104
We report on the process of lithium intercalation in V2O5 thin films deposited onto standard ITO‐coated glass substrates. The films were deposited via a well‐established sol–gel route, and the samples were examined as working electrodes in a range of potentials versus lithium reference electrode. This paper follows up issues arising from parallel spectroscopic characterizations of the films by X‐ray photoelectron spectroscopy (XPS). Specifically, the XPS examination showed that not all of the Li‐ion charge inserted was accounted for by the V(5) to V(4) reduction, but the stoichiometric balance could be maintained only by considering additional oxygens arising from the intercalation procedure, leading to Li2O formation. In this work, we have examined the possibility that the source of oxygen is the ITO substrate. To this purpose, films of V2O5 deposited on silicon substrates have been prepared using the sol–gel process and examined by XPS after electrochemical intercalation/de‐intercalation cycles. We show that in this case a perfect balance between electrochemical charge, inserted Li and reduced vanadium is obtained. A further indication of ITO‐substrate effects was obtained from examination, by the same methods, of some unconventional V2O5 films that had been co‐precipitated with a siloxane, designed to provide a template structure. The results obtained from this material imply that a barrier layer is formed at the ITO interface and, therefore, the formation of Li2O is avoided. The results are discussed in terms of the possible degradation of conventional V2O5 on ITO as a result of electrochemically induced interface reactions. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
2.
《Electroanalysis》2017,29(5):1324-1331
Vanadium oxide/poly (3,4‐ ethylenedioxythiophene)(V2O5‐PEDOT) hybrid materials were prepared in a rotating quartz plasma reactor via capacitively coupled radio frequency (RF 13.56 MHz) plasma. Thin films of V2O5‐PEDOT hybrid and V2O5 were obtained by electron beam evaporation technique onto flexible PET substrate for electrochromic devices (ECDs) applications. As a counter electrode, both RF magnetron sputtered MoO3 onto ITO coated PET and only ITO coated PET electrodes were used. Characterizations of the films were carried out via using scanning electron microscopy‐energy dispersive X‐ray spectroscopy (SEM‐EDX) and X‐ray diffraction (XRD). Hybrid ECDs results showed that synergistic effect depending on improved stability between V2O5 and PEDOT. As a result, we developed all solid complementary electrochromic devices including V2O5, V2O5‐PEDOT and MoO3 films. The electrochromic device characteristics such as electrochromic contrast, coloration efficiency, switching time were calculated from optical and electrochemical measurements. The highest coloration efficiency and optical contrast were obtained as 53 cm2/C and 17 % for V2O5‐PEDOT/MoO3‐based ECD. 相似文献
3.
Kyung-Hwa Kim Dong-Kyun Roh In Kyu Song Byung-Cheol Lee Sung-Hyeon Baeck 《Journal of Solid State Electrochemistry》2010,14(10):1801-1805
The influence of electron beam irradiation on the electrochemical properties of electrodeposited V2O5 thin films was investigated. V2O5 thin films were deposited electrochemically onto indium tin oxide-coated glass from an aqueous vanadyl sulfate hydrate (VOSO4⋅nH2O) solution using Pt and Ag/AgCl as the counter electrode and reference electrode, respectively. Electrodeposition was performed
potentiostatically at 1.7 V vs. Ag/AgCl. Electrodeposited samples were then subjected to a 1-MeV electron beam using an electron
beam accelerator at the Korea Atomic Energy Research Institute. For comparison, a control sample was not irradiated with the
electron beam. Crystallinity change before and after electron beam irradiation was investigated by X-ray diffraction and the
oxidation state of vanadium determined by X-ray photoelectron spectroscopy. Scanning electron microscopy was utilized to examine
surface morphology. It was observed that electron beam irradiation altered the oxidation state of vanadium and increased crystallinity.
Significant morphological changes of V2O5 thin films were also observed with electron beam irradiation. Cyclic voltammetry was employed to evaluate the electrochemical
properties of the synthesized V2O5 films in terms of their application as electrodes of lithium-ion battery. Compared with the control sample, which was not
irradiated with an electron beam, the electron beam-irradiated V2O5 specimens showed much higher capacitance. 相似文献
4.
The novel hierarchical flower-like superstructure NiCo2O4/reduced graphene oxide (rGO) hybrids have been successfully synthesized with a facile one-step hydrothermal process for the determination of fungicide pyrimethanil (PMT). For comparison, various structures of NiCo2O4/rGO including hexagonal nanoplates and nanorods were also synthesized. Among them, three-dimensional (3D) flower-like NiCo2O4/rGO exhibited the highest electrocatalytic activity for the oxidation of PMT. With the synergistic effect of [OMIM]PF6 ionic liquid (IL), the electrochemical sensor film (NiCo2O4/rGO/IL) further facilitated interfacial electron transfer and enhanced electrocatalytic activity for the oxidation of PMT. Under the optimum conditions, the electrochemical sensor exhibited two linear ranges of 0.1–10.0 μmol/L and 20.0–140 μmol/L for PMT with a low detection concentration of 11.0 nmol/L. Besides, the interference, repeatability, reproducibility and stability measurements were also evaluated. The proposed method was successfully applied to the detection of PMT in water, seawater, fruits and vegetables with good recovery ranging from 93% to 105%, and possessed potential applications in the analysis of real samples. 相似文献
5.
A Vanadium(V) Oxide Nanorod Promoted Platinum/Reduced Graphene Oxide Electrocatalyst for Alcohol Oxidation under Acidic Conditions
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A Pt‐V2O5/rGO ternary hybrid electrocatalyst was designed by using active vanadium(V) oxide (V2O5) nanorods and reduced graphene oxide (rGO) components. The V2O5 nanorods were synthesized by a simple polyol‐assisted solvothermal method and were incorporated uniformly onto rGO sheets by intermittent microwave heating. Subsequently, Pt nanoparticles (2–3 nm in size) were deposited over the V2O5/rGO composite by the conventional polyol reflux method. The electrocatalytic performance of the Pt‐V2O5/rGO ternary hybrid and bare Pt/rGO catalysts towards the oxidation of simple alcohols was evaluated in acidic media. The ternary hybrid catalyst exhibited higher electrocatalytic activity than bare Pt/rGO and also showed good stability. The higher electrocatalytic activity of the Pt‐V2O5/rGO ternary hybrid was attributed to a synergistic effect among the Pt, V2O5, and rGO components. In addition, oxygen‐containing species, such as OH groups, were generated on V2O5 at lower potentials. These groups were able to scavenge intermediate species such as COads on the Pt surfaces and helped to regenerate the active sites on the Pt surface more effectively for the routine alcohol oxidation reaction. 相似文献
6.
《Electroanalysis》2017,29(6):1518-1523
A sensitive and selective amperometric H2O2 biosensor was obtained by utilizing the electrodeposition of Pt flowers on iron oxide‐reduced graphene oxide (Fe3O4/rGO) nanocomposite modified glassy carbon electrode (GCE). The morphology of Fe3O4/rGO and Pt/Fe3O4/rGO was characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. The step‐wise modification and the electrochemical characteristics of the resulting biosensor were characterized by cyclic voltammetry (CV) and chronoamperometry methods. Thanks to the fast electron transfer at the Pt/Fe3O4/rGO electrode interface, the developed biosensor exhibits a fast and linear amperometric response upon H2O2. The linear range of Pt/Fe3O4/rGO is 0.1∼2.4 mM (R2=0.998), with a sensitivity of 6.875 μA/mM and a detection limit of 1.58 μM (S/N=3). In addition, the prepared biosensor also provides good anti‐interferent ability and long‐term stability due to the favorable biocompatibility of the electrode interface. The proposed sensor will become a reliable and effective tool for monitoring and sensing the H2O2 in complicate environment. 相似文献
7.
Yutaka Ohya Tsukasa Niwa Takayuki Ban Yasutaka Takahashi 《Journal of Sol-Gel Science and Technology》2005,33(3):323-326
Heterostack films of p-type NiO and n-type TiO2 semiconductors were deposited by a method of chemical solution deposition on a glass substrate having a sputtered ITO (In2O3 doped with Sn) electrode. Transparent films with total thickness of about 280 nm were obtained by heat treatments at 600°C. NiO reacted with TiO2 to give a NiTiO3 thin layer between them. The films exhibited a typical rectifying I-V behavior and this property was maintained at 300°C. The thickness of the NiTiO3 intermediate layer increase with the heating time at 600°C and leading to a decrease of the current density at low voltage. 相似文献
8.
Nirmal Prabhakar Pratima R. Solanki Ajeet Kaushik M. K. Pandey B. D. Malhotra 《Electroanalysis》2010,22(22):2672-2682
We have prepared nanocomposite films comprising of 3‐glycidoxypropyltrimethoxysilane (GOPS) and iron‐oxide (Fe3O4) onto indium‐tin‐oxide (ITO) glass plate for covalent immobilization of 21‐mer peptide nucleic acid (PNA). These films have been characterized using contact angle, atomic force microscopy (AFM), electrochemical techniques. The electrochemical response of the GOPS/ITO and Fe3O4‐GOPS/ITO electrodes has been investigated by hybridization with complementary, non‐complementary and one‐base mismatch using methylene blue as electrochemical indicator. The PNA/Fe3O4‐GOPS/ITO bioelectrode exhibits improved specificity and detection limit (0.1 fM) as compared to that of the PNA‐GOPS/ITO bioelectrode (0.1 pM). This PNA/Fe3O4‐GOPS/ITO electrode can be utilized for detection of hybridization with the complementary sequence in sonicated M. tuberculosis genomic DNA within 90 s of hybridization time. 相似文献
9.
《Electroanalysis》2017,29(11):2507-2515
In the present study, a novel enzymatic glucose biosensor using glucose oxidase (GOx) immobilized into (3‐aminopropyl) triethoxysilane (APTES) functionalized reduced graphene oxide (rGO‐APTES) and hydrogen peroxide sensor based on rGO‐APTES modified glassy carbon (GC) electrode were fabricated. Nafion (Nf) was used as a protective membrane. For the characterization of the composites, Fourier transform infrared spectroscopy (FTIR), X‐ray powder diffractometer (XRD), and transmission electron microscopy (TEM) were used. The electrochemical properties of the modified electrodes were investigated using electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry. The resulting Nf/rGO‐APTES/GOx/GC and Nf/rGO‐APTES/GC composites showed good electrocatalytical activity toward glucose and H2O2, respectively. The Nf/rGO‐APTES/GC electrode exhibited a linear range of H2O2 concentration from 0.05 to 15.25 mM with a detection limit (LOD) of 0.017 mM and sensitivity of 124.87 μA mM−1 cm−2. The Nf/rGO‐APTES/GOx/GC electrode showed a linear range of glucose from 0.02 to 4.340 mM with a LOD of 9 μM and sensitivity of 75.26 μA mM−1 cm−2. Also, the sensor and biosensor had notable selectivity, repeatability, reproducibility, and storage stability. 相似文献
10.
A [H3AgI(H2O)PW11O39]3?-TiO2/ITO electrode was fabricated by immobilizing a molecular polyoxometalate-based water oxidation catalyst, [H3AgI(H2O)PW11O39]3? (AgPW11), on a TiO2 electrode. The resulting electrode was characterized by X-ray powder diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Linear sweep voltammetry, chronoamperometry, and electrochemical impedance measurements were performed in aqueous Na2SO4 solution (0.1 mol L?1). We found that a higher applied voltage led to better catalytic performance by AgPW11. The AgPW11-TiO2/ITO electrode gave currents respectively 10 and 2.5 times as high as those of the TiO2/ITO and AgNO3-TiO2/ITO electrodes at an applied voltage of 1.5 V vs Ag/AgCl. This result was attributed to the lower charge transfer resistance at the electrode-electrolyte interface for the AgPW11-TiO2/ITO electrode. Under illumination, the photocurrent was not obviously enhanced although the total anode current increased. The AgPW11-TiO2/ITO electrode was relatively stable. Cyclic voltammetry of AgPW11 was performed in phosphate buffer solution (0.1 mol L?1). We found that oxidation of AgPW11 was a quasi-reversible process related to one-electron and one-proton transfer. We deduced that disproportionation of the oxidized [H2AgII(H2O)PW11O39]3? might have occurred and the resulting [H3AgIIIOPW11O39]3? oxidized water to O2. 相似文献
11.
Yingying Zhang Canpei Wang Dr. Yutao Dong Ruipeng Wei Prof. Dr. Jianmin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(3):993-1001
Metal oxalate has become a most promising candidate as an anode material for lithium-ion and sodium-ion batteries. However, capacity decrease owing to the volume expansion of the active material during cycling is a problem. Herein, a rod-like CoC2O4⋅2 H2O/rGO hybrid is fabricated through a novel multistep solvo/hydrothermal strategy. The structural characteristics of the CoC2O4⋅2 H2O microrod wrapped using rGO sheets not only inhibit the volume variation of the hybrid electrode during cycling, but also accelerate the transfer of electrons and ions in the 3 D graphene network, thereby improving the electrochemical properties of CoC2O4⋅2 H2O. The CoC2O4⋅2 H2O/rGO electrode delivers a specific capacity of 1011.5 mA h g−1 at 0.2 A g−1 after 200 cycles for lithium storage, and a high capacity of 221.1 mA h g−1 at 0.2 A g−1 after 100 cycles for sodium storage. Moreover, the full cell CoC2O4⋅2 H2O/rGO//LiCoO2 consisting of the CoC2O4⋅2 H2O/rGO anode and LiCoO2 cathode maintains 138.1 mA h g−1 after 200 cycles at 0.2 A g−1 and has superior long-cycle stability. In addition, in situ Raman spectroscopy and in situ and ex situ X-ray diffraction techniques provide a unique opportunity to understand fully the reaction mechanism of CoC2O4⋅2 H2O/rGO. This work also gives a new perspective and solid research basis for the application of metal oxalate materials in high-performance lithium-ion and sodium-ion batteries. 相似文献
12.
An electrode of hydrated tungsten oxide (WO3?nH2O) embedded chitosan‐co‐polyaniline (CHIT‐co‐PANI) composite was electrochemically prepared on an indium tin oxide (ITO) coated glass surface using mineral acid as a supporting electrolyte. The resulting CHIT‐co‐PANI/WO3?nH2O/ITO electrode was characterized using ultraviolet‐visible spectroscopy (UV‐vis), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), and scanning electron microscopy (SEM). The composite electrode exhibited a three‐dimensional nanofibrous structure with the diameter of the nanofibers ranging from 20 to 100 nm. The CHIT‐co‐PANI/WO3?nH2O/ITO electrode allowed for the low potential detection of NO2 gas in acidic medium. The NO2 gas sensing characteristics were studied by measuring change in the current with respect to concentration and time. Using the CHIT‐co‐PANI/WO3?nH2O/ITO electrode, NO2 gas was detected electrochemically without interference at pH 2.0 and 0.25 V vs. Ag/AgCl. The current of the electrochemical cell with the CHIT‐co‐PANI/WO3?nH2O/ITO electrode decreased linearly with an increase in NO2 gas concentration in a range from 100 to 500 ppb with a response time of eight seconds. 相似文献
13.
以石墨烯为基底,CoCl2·2H2O和NH4VO3为原料,采用水热结合热处理方法合成了Co3V2O8/石墨烯复合电极材料;采用XRD、Raman、XPS、SEM、(HR-)TEM和恒电流充放电等对材料进行了结构表征与电化学性能测试。结果表明:Co3V2O8/rGO复合材料表现出优异的放电比容量、优秀的倍率性能和稳定的循环性能(当电流密度为200 mA·g^-1,经过100次循环后,可逆放电比容量为1208 mAh·g^-1);Co3V2O8/rGO电极材料表现出优异的倍率和循环性能可以归因于:独特的石墨烯包覆结构可以有效地提高材料的导电性和增强结构的稳定性、缓解Co3V2O8粒子在循环过程中的聚结和膨胀现象;此外,Co3V2O8纳米颗粒均匀地嵌在石墨烯层间防止了石墨烯片层间的堆叠。 相似文献
14.
Abdollah Noorbakhsh Mohmmad Khakpoor Mohammad Rafieniya Ensiyeh Sharifi Mohammad Mehrasa 《Electroanalysis》2017,29(4):1113-1123
The present study describes a novel and very sensitive electrochemical assay for determination of hydrogen peroxide (H2O2) based on synergistic effects of reduced graphene oxide‐ magnetic iron oxide nanocomposite (rGO‐Fe3O4) and celestine blue (CB) for electrochemical reduction of H2O2. rGO‐Fe3O4 nanocomposite was synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X‐ray diffraction (XRD), electrochemical impedance spectroscopy and cyclic voltammetry. Chitosan (Chit) was used for immobilization of amino‐terminated single‐stranded DNA (ss‐DNA) molecules via a glutaraldehyde (GA) to the surface of rGO‐Fe3O4. The MTT (3‐(4,5‐Dim ethylt hiazol‐2‐yl)‐2,5‐diphenylt etrazolium bromide) results confirmed the biocompatibility of nanocomposite. Experimental parameters affecting the ss‐DNA molecules immobilization were optimized. Finally, by accumulation of the CB on the surface of the rGO‐Fe3O4‐Chit/ssDNA, very sensitive amperometric H2O2 sensor was fabricated. The electrocatalytic activity of the rGO‐Fe3O4‐Chit/DNA‐CB electrode toward H2O2 reduction was found to be very efficient, yielding very low detection limit (DL) of 42 nM and a sensitivity of 8.51 μA/μM. Result shows that complex matrices of the human serum samples did not interfere with the fabricated sensor. The developed sensor provided significant advantages in terms of low detection limit, high stability and good reproducibility for detection of H2O2 in comparison with recently reported electrochemical H2O2 sensors. 相似文献
15.
16.
《Electroanalysis》2018,30(9):2099-2109
Tungsten trioxide‐poly(3,4‐ethylenedioxythiophene) (WO3‐PEDOT) and tungsten trioxide‐polyfuran (WO3‐PFu) were prepared by rf rotating plasma polymerization. Electrochromic hybrid thin films were fabricated onto flexible polyethylene terephthalate (PET)/ indium tin oxide (ITO) film using electron beam evaporation method. In order to deeply characterize all films, scanning electron microscopy‐energy dispersive X‐ray spectroscopy (SEM‐EDS) and electrochemical impedance spectroscopy (EIS) techniques were used. The counter electrode effect on plasma modified WO3 nano hybrids‐based electrochromic devices (ECDs) was evaluated. By incorporating flexible vanadium pentoxide (V2O5) film as counter electrode, complementary ECDs were constructed through combining the hybrid flexible films (WO3‐PEDOT, WO3‐PFu) as working electrodes, which exhibit highly efficient electrochromic performance with low voltage operation. Especially, WO3‐PEDOT/V2O5‐based ECD owns a high optical modulation of 61.5 % at 750 nm driven by −1.0 V (coloration) and +1 V (bleaching) with fast response times (coloration time: 13.58 s, bleaching time: 8.07 s) and a high coloration efficiency of 527 cm2 C−1. This study can supply useful and efficient avenue for designing flexible complementary electrochromic device for energy‐saving flexible electronics. 相似文献
17.
Fabrication of a Fe2O3 Nanoparticles Implantation‐modified Electrode and its Applications in Electrochemical Sensing
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A novel Fe2O3 modified indium tin oxide electrode (Fe2O3/ITO) was fabricated by iron ion‐implantation method first, and then annealed at 300 °C. Fe2O3/ITO reveals good catalytic performance toward hydrogen peroxide (H2O2) in phosphate buffer solution due to the Fe(II)/Fe(III) redox couple. Amperometric response shows a linear dependency on the H2O2 concentration ranging up to 360 μM with a detection limit of 0.3 μM. Moreover, electrocatalytic activity based on rarely reported higher oxidation states of iron (tentatively assigned to Fe(IV)) was shown to allow the reliable detection of glucose and cysteine. The results show promising application potential of the proposed electrode. 相似文献
18.
Dr. Annika Buchheit Britta Teßmer Dr. Marina Muñoz-Castro Prof. Hartmut Bracht Prof. Hans-Dieter Wiemhöfer 《ChemistryOpen》2021,10(3):340-346
This work examines the proton intercalation in vanadium pentoxide (V2O5) thin films and its optical properties in the near-infrared (near-IR) region. Samples were prepared via direct current magnetron sputter deposition and cyclic voltammetry was used to characterize the insertion and extraction behavior of protons in V2O5 in a trifluoroacetic acid containing electrolyte. With the same setup chronopotentiometry was done to intercalate a well-defined number of protons in the HxV2O5 system in the range of x=0 and x=1. These films were characterized with optical reflectometry in the near-IR region (between 700 and 1700 nm wavelength) and the refractive index n and extinction coefficient k were determined using Cauchy ’s dispersion model. The results show a clear correlation between proton concentration and n and k. 相似文献
19.
《Electroanalysis》2006,18(3):275-281
Mesoporous V2O5/Nafion composite films have been used for the immobilization of tris(2,2′‐bipyridyl)ruthenium (II) (Ru(bpy) ) on an electrode surface to yield a solid‐state electrogenerated chemiluminescence (ECL) sensor. The electrochemical and ECL behavior of Ru(bpy) ion‐exchanged into the composite films has been characterized as a function of the amount of Nafion incorporated into the V2O5/Nafion composite. The composite film with 80% Nafion content has the largest pore diameter (4.19 nm) and yields the maximum ECL response for tripropylamine (TPA) because of the fast diffusion of analyte into the film with large pores. Due to the enlarged pore size and enhanced conductivity of the V2O5/Nafion composite, the present ECL sensor based on the composite films exhibited around 2 orders of magnitude higher ECL response and one order of magnitude lower detection limit for TPA (10 nM) compared to those obtained with the ECL sensors based on other types of sol–gel ceramic/Nafion composite films such as SiO2/Nafion and TiO2/Nafion. 相似文献
20.
Mingzhe Jia Fenfen Liang Jiao Jiao Shuoqi Li Jingbo Hu 《Journal of Solid State Electrochemistry》2013,17(3):655-660
In this paper, a gold nanoparticle-modified indium tin oxide electrode (Au/ITO) was prepared without the use of any cross-linker or stabilizer reagent. The prepared Au/ITO was used as a new platform to achieve the direct electron transfer between Hb and the modified electrode. The proposed electrode exhibited a pair of well-defined redox peaks with a formal potential of ?0.073 V (vs. Ag/AgCl). The immobilized Hb showed excellent electrocatalytic activity toward H2O2 and the electrocatalytic current values were linear with the increasing concentration of H2O2 ranging from 1.0?×?10?6?M to 7.0?×?10?4?M. The detection limit was 2.0?×?10?7?M (S/N?=?3) and the Michaelis–Menten constant was calculated to be 0.2 mM. The proposed electrode also showed high selectivity, long-term stability, and good reproducibility. 相似文献