Physical Chemistry Commons^™

Study Of The Cathod Of The Amperometric Glucose Sensor, Xiu-Juan Yu, Ding Zhou

Journal of Electrochemistry

The possibility for several kinds of conducting materials used as the cathode of glucose sensor was studied by the cathode polarization curves. It was shown that the titanium coated by RuO₂/TiO₂ is stable to the electrochemical corrosion and it could promote the generation of hydrogen. H₂O₂ could be detected in the electrochemical system constructed by the anode of graphite powder and epoxy resin composite and the cathode of titanium coated by RuO₂/TiO₂ in the potential range of 0.6V～0.8 V. It can be used as the cathode of glucose sensor instead of …

A Study For The Data Analysis Of Electrochemical Noise With Wavelet Analysis, Hong-Bo Ding, Bao-Yun Xia, Zhong-Xiao Pan, Chang-Jian Lin

Journal of Electrochemistry

In the process of electrochemical dynamics system, the phenomenon of the random fluctuations of electrochemical parameters (electrode potential, cell current, etc.) is called “Electrochemical Noise”(ECN). Wavelets analysis is one new data analysis technique which has undergone a breakthrough in the area of mathematics and singnal processing in recent years. In this paper, the technique of continuous wavelet transform has been employed to investigate electrochemical noise data, and the chaotic nature of corrosion process has been manifested.

Determination Of Diclofenac In Voltalin Tablets By Differential Pulse Voltammetry, Gui-Fen Wang, Yuan-Zhe Piao

Journal of Electrochemistry

Diclofenac, dissolved in a base solution of chlorhydric acid, showed a sensitive oxidation peak at 0.91 V (vs.SCE) when the solution was cyclically swept from +0.6 to +1.2 V(vs.SCE) by differential pulse voltammetry at GCE. There was a good linear relationship between the differential pulse peak current and the concentraion of diclofenac in the range from 5.0×10^-7 to 6.0×10^-6 mol/L, and the relative standard deviation is 3.5%(n=10). When determining the content of diclofenac in voltalin tablets, we have got the same results by this method as ultraviolet spectrophotometry.

A Gas Analysis Method For Determining The Perchlorate Current Efficiency And Other Applications, Zhi-Gang Shao, Bao-Lian Yi

Journal of Electrochemistry

A method for determining the current efficiency by means of measuring the flow capacity of the cell gas in a perchlorate cell has been proposed. The perchlorate cell system was equipped with an oxygen cathode or a Na⁺ ion exchange membrane. This method is simple and convenient as well as accurate in the evaluation of the perchlorate current efficiency in the perchlorate cell as compared with the traditional methods of analysis. It is useful in the investigation of electrochemical problems with high perchlorate concentration, as well as for the assessment of electrocatalytic performance of anode materials.With an oxygen cathode …

Surface Enhanced Raman Spectroscopic Study Of Scn- Adsorbed At The Copper And Gold Nanowire Arrays, Jian-Lin Yao, Guo-Ping Pan, Kuan-Hong Xue, Yong Xie, Jing Tang, Bin Ren, Dong-Mei Sun, Bing-Wei Mao, Zhong-Qun Tian

Journal of Electrochemistry

Two-dimensional arrays of Cu and Au nanowires have been fabricated by template synthesis method, using the anodic aluminum oxidation films as the template. The morphology of the nanowire array was monitored by atomic force microscope (AFM) in the dissolution processes of the alumina film. Based on the probe molecule strategy, the spectral feature of SCN^- adsorbed at the Cu and Au nanowires with different diameters has been investigated by surface enhanced Raman spectroscopy (SERS). The results reveal that the intensity of the SERS bands depends on the length of the exposed nanowires. The C≡N stretching vibration frequency (ν_{CN …}

In Situ Ftirs Studies Of The Electrochemically Induced Coupling Of Osmium Nitrido Species In Acetonitrile, Sheng-Pei Chen, Shi-Gang Sun

Journal of Electrochemistry

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The Ac-Impedance Analysis For Pluse Oxide Film Of Aluminium Alloy, Ai-Ling Du, Xi-Cheng Ma, He-Ming Zhang

Journal of Electrochemistry

Bode diagrams for aluminum PC (abbreviated from pulse current) oxide films were first obtained by AC-impedance measurements in a wide range of frequency. The experimental results show that different kinds of electrical equivalent circuits can be used for representing PC films and DC (abbreviated from direct current) oxide films separately, the main differences between them are their porous layers, the PC films are more even with little defects.Those are also verified by SEM and V-I characteristic curve measurements.

Calculation Of Corrosion Rate Of Passive Metals With Charge Curve Analysis Technique, Yuan-Sheng Zhang, Min Gong

Journal of Electrochemistry

This work contains two parts: (1) A charge curve equation having no appro-ximation for passivated metal corrosion systems is derived and compared with the routine charge curve equation, which is virtual only when the polarization is minim(linear range). (2) It is simpler to analyze charge curve data by from of charge differential equation than from charge curve equation. After the charge curve data are measured, the slope of charge curve is computed by numerical differentiation method, then the charge differential equation may be transformed to a set of linear equations using polynomial approximation. The electrochemical parameters of corrosion system would …

Study On The Microband Array Electrode-Based Glucose Microsensor, Neng-Qin Jia, Chui-Jue Sun, Lin Gao, Zong-Rang Zhang, Jian-Zhong Zhu, Guo-Xiong Zhang

Journal of Electrochemistry

The microband array electrode (MAE) consisting of 11 Pt microband of 5 m in wide, 2000 m long and 85 m gap was fabricated with a thin film techology. The MAE was characterized by means of cyclic voltammetry in a solution of K₃Fe(CN)₆ and H₂O₂. The results showed higher current density on MAE than on conventional Pt eletrode due to the strong edge effect of the former. A glucose microsensor was constructed with the substrate electrode of microband array. Microband array electrode was modified by Nafion followed by the immobilization of ferrocene onto …

In Situ Ftir Spectroelectrochemical Study Of Palladium Hexacyanoferrate Thin Film Deposited On Glassy Carbon Electrode, Ai-Li Bo, Xiang-Qin Lin

Journal of Electrochemistry

The electrochemically deposited Palladium hexacyanoferrate thin film on Glassy Carbon electrode (PdHCF|GC) has been studied in HCl, KCl and NaCl solutions by in-situ external reflection FTIR spectroelectrochemical technique. It is found that the behavior of the electroactive PdHCF film can be understood in terms of two states: Pd₂Fe(II)(CN)₆ formed in the inner layer and (M⁺)2Fe(II)(CN)₆ (M⁺: electrolyte cation) formed in the outer layer. The inner layer is oxidized at E_m=0.87 V in 1 mol/L KCl, while for the outer layer Em=0.77 V(vs. Ag/AgCl). In 1 mol/L NaCl or HCl solutions, …

Reply To Comment On ‘Nondipole Resonant X-Ray-Raman Spectroscopy: Polarized Inelastic Scattering At The K Edge Of Cl2,’, J. D. Mills, J. A. Sheehy, T. A. Ferrett, S. H. Southworth, R. Mayer, Dennis W. Lindle, P. W. Langhoff

Chemistry and Biochemistry Faculty Research

Mills et al. Reply: In their Comment on our Letter [1], Gel’mukhanov and Ågren [2] reiterate recent assertions [3] based on their earlier theoretical studies [4]. The primary purpose of their Comment is apparently to refute our stated conclusion that core-excited-state localization/ delocalization mechanisms are irrelevant to interpretations of reported Raman scattering experiments on homonuclear diatomic molecules.

Study Of The Effect Of Rare Earth Ions On Dna Using Cyclic Voltammetry And Spectroscopy, Hei-Bai Shen, Yu-Zhuan Kang, Hai-Feng Yang, Lin Yu, Zong-Rang Zhang

Journal of Electrochemistry

The interaction between rare earth ions(e.g. Eu³⁺ ,Ce³⁺, Er³⁺, Sm³⁺, Tb³⁺, La³⁺ and Nd³⁺) and DNA had been investigated by using Cyclic Voltammetry, Ultraviolet and Raman Spectroscopy. After the adding of Ce³⁺ ion to DNA solution, the cathodic peak current of Ce³⁺ ion reduction was found to decrease obviously, and the anodic peak current to decrease even more significantly. Differential UV spectra of Ce³⁺ ion depicted hyperchromic effect after the reaction of these two species and a new peak of 272 nm was found. Differential …

Direct Electro-Oxidation Synthesis Of D-Arabinose On Spectroscopic Graphite Electrode, Hei Wei, Huang Ying

Journal of Electrochemistry

D Arabinose synthesized by direct electro-oxidative decarboxylation of D gluconate on graphite electrode from aqueous solutions. The effects of D gluconate concentration, electrolysis potential, temperature and electrolyte composition on the current efficiency and product yield of electrosynthsis are discussed. The laboratory scale electrosynthesis was achieved with flow through cell. The optimum technology conditions for electrosynthesis were obtained with orthogonal design method. Both galvanostatic and potentionstatic conditions have been exploited, the later was found to be more effective.

Auger Resonance Decay Process In Ar 2p Shell Excitation And Ionization, Y. Lu, Wayne C. Stolte, J.A. R. Samson

Chemistry and Biochemistry Faculty Research

The production and subsequent autoionization of the Ar⁺ (¹D₂)6d¹ satellite state that is formed either by shake-up or recapture during the Auger decay of a 2p vacancy in Ar has been studied by photoelectron spectroscopy in the energy region from 243 to 256 eV. The creation of near zero energy electrons below and immediately above the Ar 2p ionization threshold is discussed. Some ambiguous points in previous studies are clarified.

Electrochemical Determination Of Trace Amouns Of Gold(Ⅲ)By Cathodic Sptripping Voltammetry Using A Carborn Paste Electroele Modified With Bacteria, Rong-Zong Hu, Hao Xu, Jin-Kun Fu, Wen-Yun Hu, Yan-Zhen Chen

Journal of Electrochemistry

An electrochemically pretreated carbon paste electrode modified with bacteria has been studied and used for determination of trace amounts of gold(Ⅲ). A detection limit of 1 ng/mL was obtained by applying cathodic stripping valtammetry. There is a linear relationship between the concentration and peak height in the range of 10～100 μg/mL. The ralative standard deviation of the response to 84.7 μg/mL Au(Ⅲ) is 3.43%.

In-Situ Raman Spectroscopic Study Of The Oxidation And Reduction Of Ag Electrode In Na2So4, Yan-Xia Chen, Kai-Qi Huang, Zhong-Qun Tian

Journal of Electrochemistry

In-situ Raman spectroscopy combined with cyclic voltammogram measurements was used to investigate formation of oxygen species at Ag electrode surfaces during the oxidation and reduction process in 0.1 mol/L Na₂SO₄ solution. The time dependent Raman spectra show that at potentials positive of 0.2 V, adsorption of oxygen atom occurs, while at the potentials positive of 0.4 V, some oxygen atoms migrate into subsurface of the Ag electrode and the other form strongly bound oxygen on the surface through chemical bond. At the same potentials, part of the silver atoms are oxidized and form Ag₂SO_{4 …}

Neutral Dissociation Of Hydrogen Following Photoexcitation Of Hcl At The Chlorine K Edge, D. L. Hansen, J. Cotter, G. R. Fisher, K. T. Leung, R. Martin, Paul Neill, Rupert C. Perera, I. A. Sellin, Marc Simon, Y. Uehara, B. Vanderford, S. B. Whitfield

Chemistry and Biochemistry Faculty Research

Time-of-flight mass spectroscopy was used to study the relaxation dynamics of HCl following photoexcitation in the vicinity of the Cl K edge (~2.8 keV) using monochromatic synchrotron radiation. At the lowest resonant excitation to the 6ơ* antibonding orbital, almost half of the excited molecules decay by emission of a neutral H atom, mostly in coincidence with a highly charged Cln1 ion. The present work demonstrates that neutral-atom emission can be a significant decay channel for excited states with very short lifetimes (1 fs). [S1050-2947(98)03604-X]

Double Photoionization Of Helium, James A.R. Samson, Wayne C. Stolte, Z. X. He, Y. Lu, J. N. Cutler, R. J. Bartlett

Chemistry and Biochemistry Faculty Research

The cross sections for double photoionization of helium and the ratios of double to single ionization have been measured from the double-ionization threshold to 820 eV. The results are in very good agreement with several recent calculations.

Spectroscopic Investigation Of Ion Transport Mechanisms In Polyacrylonitrile Based Electrolytes, Zhaoxiang Wang, Biying Huang, Rongjian Xue, Xuejie Huang, Liquan Chen

Journal of Electrochemistry

Raman, IR, X-ray photoelectron (XPS), and NMR spectra of components in polyacrylonitrile based electrolytes have been studied. It is found that there are strong interactions among the components though different systems show different interaction characteristics. A concept of competition is proposed between the polymer matrix and the plasticizer on associating with the Li⁺ ions. By analyzing the important functions of the plasticizer, a possible mechanism of the ions transport in the polymer electrolyte is suggested.

Investigation On The Ellipsometry For The Detection Of Nickel Through Anodic Stripping Voltammetry, Wei Zhu, Yu-Ru Yang, Zong-Qing Huang

Journal of Electrochemistry

The ellipsometry with a new parameter Vop and anodic stripping voltammetry are used to analyze the nickel ions solutions with different concentration of 10^-6～10^-9 mol/L. It is shown that the results given by both methods are identical and the sensitivity and accuracy of ellipsometry are higher than anodic stripping voltammety.

The Electrode Process Of Some Organic Dyes Studied By Spectroelectrochemical Technique In Situ, Yinxuan Tang, Hangsheng Yang, Baoen Shen

Journal of Electrochemistry

Spectroelectrochemistry especially with in situ measurement in a cell provides a very useful mthodology for measuring the parameters of electrode process. In this paper, we report the determination of formal potentials, the number of electron transfer, the diffusion coefficient, the heterogeneous electron transfer rate constant and the transfer coefficient of some organic dyes (Methyelene blue, Neutral red, Indigo carmine) using spectroelectro chemical technique in situ.

Nondipole Resonant X-Ray-Raman Spectroscopy: Polarized Inelastic Scattering At The K Edge Of Cl2, J. D. Mills, J. A. Sheehy, T. A. Ferrett, S. H. Southworth, R. Mayer, Dennis W. Lindle, P. W. Langhoff

Chemistry and Biochemistry Faculty Research

Experimental and theoretical studies are reported on the inelastic (Raman) scattering of wavelength-selected polarized x rays from the K edge of gas-phase chlorine molecules. The polarized emission spectra exhibit prominent nondipole features consequent of phase variations of the incident and emitted radiation over molecular dimensions, as predicted by the Kramers-Heisenberg scattering formalism. Issues pursuant to the detection of core-hole localization by resonant Raman scattering from homonuclear diatomic molecules are critically examined. [S0031-9007(97)03486-8]

Effects Of Tunneling Electrons And Local Field On Nanometer Region Solid / Liquid Interfacial Reactions ——Potential Controlled Stm Induced Nanoscale Modification Of H Terminated Si(111) Surfaces, Zhaoxiong Xie, Xiongwei Cai, Caihui Shi, Bingwei Mao, Zhaowu Tian

Journal of Electrochemistry

H-terminated n-Si(111) surface was found to be etched in 0.5% HF solution in nanometer scale while scanning the STM tip when the substrate potential was somehow lower than the open circuit potential at tunneling condition of V_b=+1.0 V (tip positive), I_t=1 nA. Much more stable Si surface was achievable at potentials much more negative than the open circuit potential (such as 500 mV negative to OCP) under the same tunneling condition. Furthermore, the etching rete at less negative potential was found to be somehow related to the tunneling current. These results indicate that the STM induced …

Cross Sections For The Production Of He+ (Np) 2p0 States By 50 To 150 Kev Proton Impact On Helium, Wayne C. Stolte, R. Bruch

Chemistry and Biochemistry Faculty Research

Cross sections have been measured for the production of He⁺ (np) ²P^o states, n=2,3,4, by proton impact on helium over a projectile velocity range of 1.42–2.45 a.u. (50 ≤E≤150 keV). Cross sections were determined by measuring the extreme ultraviolet photons emitted from excited He1 ions. The data indicate a lower energy than expected for the maximum cross section. A comparison of the present results in terms of projectile energy dependance with the cross sections for excitation to He (1snp) ¹P^o, ionization, and total electron capture suggests the primary mechanism …

A Review Of Differential Electrochemical Mass Spectroscopy Techniqueⅰ. The Principle And Development Of Dems, Fujikawa Keikichi, Li Feng

Journal of Electrochemistry

No abstract provided.

Time-Resolved Electron Spin Resonance Spectroscopy For In-Situ Studies Of Electrochemical Systems, Lin Zhuang, Juntao Lu

Journal of Electrochemistry

No abstract provided.

Surface Raman Spectra Obtained From Various Electrodeposited Transidon Metals, Jingsong Gao, Bin Ren, Qunjian Huang, Zhongqun Tian

Journal of Electrochemistry

Good quality potential-dependent surface Raman spectra of pyridine were obtained for the first time from a series of transition metals, e. g., Fe, Co, Ni, Ru, Rh, Pd and Pt, which were electrodeposited on non-SERS-active substrates. The influences of the applied potential and the nature of metal on the adsorption behaviors were discussed briefly. This result illustrates that Raman spectroscopy is becoming a more general and powerful tool to study various electrochemical interfaces.

In Situ Studies Of Copper Electrodepostion On Hopg By Using Ecstm, Zhaoxiong Xie, Bingwei Mao, Xiangdong Zhuo, Jiqian Mu, Zhaowu Tian

Journal of Electrochemistry

In this paper, copper electrodepostion on HOPG had been in situ studied by using a homebuilt electrochemical scanning tunneling microscopy (ECSTM). Three dimensional nucleation and subsequent growth of copper crystals were found as the initial stage of copper deposition on HOPG. In the case of lower overpotential or lower concentration of Cu²⁺ , the bulk deposited copper layer tended to form smooth terraces, and grow at the edge of steps. The terraces were stable to some extent, which made it possible to be observed with atomic resolution. At a higher overpotential, the crystal size of copper were somehow smaller. …

Statistical Mechanical Treatment For The Electrical Double Layer At Ities: Analysis Of Mvn Model, Jintian Wu, Shengpei Chen, Hui Wang, Wenduan Su

Journal of Electrochemistry

A statistical mechanical treatment for electrical double layer at the interface between two immiscible elecrolyte solution (ITIES) is presented by using grand canonical method based on the MVN model.

For the MVN model, the ITIES was represented by that the two space charge regions are separated by an inner layer of the oriented solvent molecules. Assuming that the ions were allowed to penetrated into the solvent compact layer over some distance, then the grand canonical partition function of the inner layer at ITIES can be given. While the mean field approximation is employed to estimate the interactive potential energy of …

The Applications Of Poap Ni2+ Films Modified Electrode As Sensor For Alcohol, Bingzeng Hua, Wenyun Hu, Yanzhen Chen

Journal of Electrochemistry

POAP Ni²⁺ films modified electrode can electrocatalyzes significantly the oxidation of alcohol. The modified electrode can be used as the electrochemical sensor for the detection of alcohol. But the oxidation of alcohol is effected by the thickness of films、the concentration of nickel ion in films, pH of electrolyte, as well as temperative. All of those conditions have been studied in order to achieve stable response current during the oxidation of alcohol, and the relation between concentration and current has been made. At last the major characteristic parameters, such as the low limitation of concentration, the response time, the ability …