Physical Chemistry Commons^™

A Study On The Performance Of Matrix Prepared By Tape Cast And Its Molten Carbonate Fuel Cells (Mcfcs), Hua-Xin Lin, Bao-Lian Yi, Li Zhou, Chang-Qing He, Lian-Ying Kong, En-Jun Zhang

Journal of Electrochemistry

The matrix prepared with γ-LiAlO₂ powder and by tape cast displayed higher ability of preventing from gas cross over and lower ohmic polarization. The voltages of the stack (three cells, 122 cm²) stacked with the matrix were 2.02 and 1.78 V at 200 and 246 mA/cm², respectively, and the output power reached 53.4 W. The cell (28 cm ²) voltages were 0.85 and 0.75 V at 200 and 300 mA/cm², respectively, and the output power was about 6.6 W. Compensating the shrinkage of matrix in stacking cells promoted the enhancement of the …

The New Developments Of Molten Salt Electrochemistry, Qi-Qin Yang, Shu-Zhen Duan

Journal of Electrochemistry

New developments in the areas of molten salt systems, molten salt batteries and power, electrodeposition of metals and alloys, electro synthesis of compound materials in molten salts are presented. Application of molten electrochemistry to the energy supply and consumption, global environment, resources and recycling are predicted.

Rhodium As A Ubiquitous Substrate For Surface Enhanced Raman Spectroscopy, Bin Ren, Xu-Feng Lin, Zhong-Qun Tian

Journal of Electrochemistry

Raman Spectroscopy is a powerful technique in characterizing the molecular structure at the molecular level. However, only after the discovery of surface enhanced Raman scattering (SERS) effect, has it become one of the most widely used technique in surface sciences. The limitation that only Ag, Au and Cu can produce prominent SERS signal of practical significance, greatly hinders the application of this technique. Recently our group has made great progress in extending SERS to pure transition metal surfaces, such as Pt, Ni, Fe, Co etc.

Two-Dimensional Surface Raman Imaging Of A Roughened Iron Electrode In Saline Water, Pei-Gen Cao, Jian-Lin Yao, Jun-Wei Zheng, Bin Ren, Ren-Ao Gu, Zhong-Qun Tian

Journal of Electrochemistry

The analysis of the composite and distribution of iron oxide due to pit corrosion in saline solutions (3.4% NaCl) is of great importance. Many electrochemical methods, XPS, and other photoelectronic techniques have been applied to this domain. Surface enhanced Raman scattering (SERS) spectroscopy can provide the vibrational information of surface species with high sensitivity and is very useful in the study of surface chemistry of iron. Notwithstanding, the application of SERS in iron corrosion is hampered for its SERS-inactivity. Efforts have been devoted to extend the use of SERS to the study of iron.

The Charge Transfer Effect Of Sers Induced By The Electrochemical Hydrogen Evolution Reaction, Feng-Ming Liu, Qi Han, Yan-Xia Chen, Qi-Ling Zhong, Bin Ren, Zhong-Qun Tian

Journal of Electrochemistry

As one of the important mechanisms of SERS, the charge transfer (CT) enhancement requires the strong interaction of the adsorbed species with the substrate in order to permit the transition of charge between the metal Fermi level (energy state) and the molecular orbital. The high enhancement needs the match of the energy gap between the Fermi level (or surface state) and the orbital energy level of the adsorbed molecules with the energy of the incident light. The electrode Fermi level is usually adjusted by the applied potential to satisfy the CT resonance. For the electrochemical reaction process, the frontier orbital …

Fabrications And Characterizations Of Porous Silicon By Two-Step Techniques Ii: Pulse Current Application, Xuan Cheng, Feng-Ming Liu, Zuo-Xin Wen, Chang-Jian Lin, Zhong-Qun Tian, Ru Xue

Journal of Electrochemistry

Porous silicon structures were formed by two-step technique consisting of pulse current applications in 1:1 hydrofluoric acid and ethanol solutions and chemical oxidation in 20% nitric acid solutions. Their surface morphologies and optical properties were characterized by scanning electron microscope (SEM) and Raman spectrometer, and compared with those obtained by constant current application. More uniform pore formation on p(100) silicon wafers was observed by pulse current application. Illumination with an ultraviolet lamp during the pulse current application accelerated the macropore formation, accordingly, the optical properties were changed.

Eis Characteristics Of Anodic Dissolution For P110 Steel Under Co2 Environment, Jing Li, Dong-Bai Sun, Hong-Ying Yu, Hui-Min Meng, Hui-Qin Li, De-Jun Yang

Journal of Electrochemistry

Effect of temperature on the electrochemical impedance spectroscopy for P110 steel at anodic polarized potential was investigated in simulated CO₂ saturated oil produced water. The results demonstrated that in the range from room temperature to 90 ℃, there was a critical temperature , below which a three time constant impedance spectrum was observed and above which a two time constant spectrum was shown. A reasonable explanation was given to this phenomenon in an effort to elucidate the mechanism of anodic dissolution and characteristics of CO₂ corrosion.

How Can Direct Mthanol Fuel Cell Benefit From Carbonate Media, Lin Zhuang, Yang Wang, Jun-Tao Lu

Journal of Electrochemistry

The kinetics of methanol oxidation and oxygen reduction in 0.5 mol/L K₂CO₃ were compared with those in 0.5 mol/L H₂SO ₄. Experiments revealed that carbonate media could be more beneficial to direct methanol fuel cell(DMFC). Firstly, both electrode reactions show better performance in the carbonate than in the acid; secondly, materials other than noble metals become possible to be used as the anodic and cathodic catalysts; thirdly, the potential dectease caused by methanol crossover could be depressed by using metal oxide catalysts not stable in acid, such as MnO₂.

Serrs And Electrochemical Study Of Yeast Iso-1-Cytochrome C Mutant F82h, Jun-Wei Zheng, Ren-Ao Gu, Tian-Hong Lu, Chumanov George, M. Cotton Therese

Journal of Electrochemistry

The redox properties of iso-1-yeast cytochrome c and its mutant F82H were studied by surface-enhanced Raman spectroscopy and cyclic voltammetry. The results showed that the replacement of phenylalanine-82 with histidine led to a more stable global structure of the protein. A negative shift in the redox potential of the mutant relative to that of wild type protein is ascribed to a ligand switching reaction during the redox processes.

Synthesis Of Limn2O4-ΔClΔ Cathode Material By Like-Sol-Gel Methode, Zhao-Yong Chen, Yi He, Xing-Quan Liu, Zhi-Jie Li, Zuo-Long Yu

Journal of Electrochemistry

LiMn₂O_4-δCl_δ was synthesized by like sol gel methode, with calculated LiOH·H₂O, Mn(No₃)₂⋅6H₂O and LiCl·H₂O, and made electrochemical test with these compounds as positive materials. Result demostrated that LiMn₂O_4-δCl_δ cathode material has exellent stability and nearly no capacity loss after reaching stability.

Raman Spectroelectrochemical Study On Bioactive Molecules, Xiao-Wei Cao, Hai-Feng Yang, Zhe Su Meng Xiao Yun Wang, Xia-Qin Wu, Zong-Rang Zhang

Journal of Electrochemistry

Electron-transfer reaction is known to be one of the key reactions for generating biological functions. Mechanism revelation at a molecular level of such kind reactions is to be very helpful for us to understand life essence. In fact, surface enhanced Raman scattering (SERS) is one of the most powerful tools for the study on metal-electrolyte and metal-vacuum interfaces since 1970's. Moreover, Raman spectroscopic study in enzymology has provided attractive results during last twenty-five years.

In Situ Raman Spectroelectrochemical Characterization Of The Prussian Blue/Platinum Modified Electrode, Xiao-Wei Cao, Rong Wang, Gui-Hua Wang, Zong-Rang Zhang

Journal of Electrochemistry

Prussian Blue is known to be deposited electrochemically on the electrode surface, producing a dense redox active layer. Since the Prussian Blue modified electrode was first reported by Neff in 1978, different in situ spectroelectrochemical techniques have been widely used to investigate its electrochemical mechanism. But no research work related to the in situ Raman spectroscopic studies on it has been reported. In this paper we try to characterize the nature of thin Prussian Blue films on platinum substrates with in situ Raman spectroelectrochemical technique.

Adsorption Behavior Of Co At The Ultrathin Rh And Pt Film Electrodes, Yong Xie, Xiao-Qin Li, Bin Ren, Zhong-Qun Tian

Journal of Electrochemistry

Pt group metals have been widely used in catalysis such as hydrogenation of organic compounds and the oxidation of carbon monoxide. The information about CO adsorption on the Pt group surfaces and the influence of other surface species, such as hydrogen and CO₂ will be greatly helpful to elucidate the adsorption behavior of CO on Pt group metal surfaces and get a deeper understanding of catalytic mechanisms of Pt group metals. Surface enhanced Raman spectroscopy (SERS) has been becoming an increasingly important means to characterize the electrochemical metal solution interface over the past two decades. Our laboratory has successfully …

Adsorption And Oxidation Of Ethanol On Nm-Pt/Gc Electrode Ii. Eqcm And In-Situ Ftir Spectroscopic Studies In Acid Media, Guo-Liang Chen, Sheng-Pei Chen, Zhi-You Zhou, Chun-Hua Zhen, Shi-Gang Sun

Journal of Electrochemistry

The adsorption and oxidation of ethanol on nm Pt/GC electrode in acid solutions containing 0.1 mol·L ^-1 H₂SO₄ +0.1 mol·L ^-1 CH₃CH₂OH was investigated by using cyclic voltammetry, EQCM and in situ FTIR spectroscopy. The experimental results demonstrated that the oxidation of CH₃CH₂OH is closely relaed to solution acidity and oxygen species on electrode surface; CH₃CH₂OH was oxidized on nm Pt/GC electrode in acidic media via a dual path reaction mechanism, i.e . CH₃CH₂OH may be oxidized into CO₂ through …

The Photoelectrochemistry Of Tio2-Polyaniline Composite Film, Huai-Guo Huang, Zhi-Xin Zheng, Jin Luo, Hong-Ping Zhang, Ling-Ling Wu, Zhong-Hua Lin

Journal of Electrochemistry

A TiO₂ and polyaniline (PANI) composite film was obtained by electrochemical methods. The SEM image of the composite film showed that the PANI film is almost completely covered with TiO₂ efficiency. The spectra of photocurrent for the TiO₂-PANI composite film were different from these of TiO₂ film photosensitized by PANI. The bandgap energy of TiO₂ film on partially oxidized PANI film was determined as 3.0 eV by the threshold energy of photocurrent band for TiO₂. The spectra of photocurrent for partially oxidized PANI film electrode suggested that it has the characteristics of …

Catalytic Effect Of Cl- On Electrodeposition Of Binary Zinc Alloys With Iron Group Metals, Ren-He Yin, Zheng-Hua Fang, Wei-Min Cao, A.Za Karia, Rong-Ming Zhou

Journal of Electrochemistry

Zinc iron group metal alloys were deposited under coulostatic (10C⋅cm^-2) at 40 ℃ chloride baths. The deposited alloys were quantitatively analyzed by Atomic Absorption Spectrometry. The current efficiency, percent content and partial polarization curves were obtained by the results. The morphology of the deposits was observed by means of Scanning Electron Microscopy(SEM). We observe that the electrodeposition of zinc iron group metal alloys is one of the best known examples of anomalous codeposition. We found the catalytic effect of Cl^- on the electrodeposition behavior of iron group metal. Overpotential of iron group metal droped abruptly at high …

Rayleigh And Raman Scattering, David W. Ball

Chemistry Faculty Publications

Details the molecular aspect of Raman spectroscopy. Overview on the molecular absorption process; Information on Rayleigh scattering; Effects of the Raman scattering.

Effects Of External Electric Field On The Interfacial Properties Of Weakly Dipolar Fluid, V. B. Warshavsky, T. V. Bykov, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

In the framework of modified mean-field density-functional theory, effects of a uniform electric field on the interfacial properties of a model dipolar fluid are studied. Both density and orientational order-parameter profiles of the planar vapor-liquid interface are obtained as a function of the field strength. For the dipolar fluids with reduced dipole moment μ₀^*0^*E*/T*!1) can shift the surface tension by few percent. We also find that the electric field actually reduces the thermodynamical surface tension but enhances the mechanical surface tension at the equimolar dividing surface. To detect these field effects on …

Uranium-Uranium Collisions At Relativistic Energies, Bao-An Li, Matt Tilley

Journal of the Arkansas Academy of Science

No abstract provided.

Kinetics Of Proteolyic Enzymes Monitored Online With Mass Spectrometry, Jennifer L. Rutherford

Theses, Dissertations and Capstones

On-line reaction monitoring using electrospray ionization mass spectrometry was investigated with the goal of kinetically distinguishing the isomeric amino acids leucine and isoleucine. Leucine and isoleucine are isomers of identical mass (113.0946 Da) which are impossible to distinguish by their mass-to-charge ratios. These isomers are a source of ambiguity when sequencing peptides with exoproteases and mass spectrometry. Here we investigated the kinetics of on-line enzymatic reactions involving exoproteases for differentiating between leucine and isoleucine.

The kinetics of the stepwise exopeptidase degradation of 12 leucine/isoleucine isomeric peptides was monitored in real-time with a Finnigan Mat LCQ with an electrospray ionization source. …

Stm And Electrochemical Investigation Of Homoepitaxial Boron-Doped Cvd Diamond Films, John B. Cooper, Jason A. Moulton, Sacharia Albin, Bing Xiao

Chemistry & Biochemistry Faculty Publications

Homoepitaxial growth of boron-doped CVD diamond films was carried out on (100) and (111) oriented substrates. Atomic resolution images were obtained for both (100) and (111) surfaces using scanning tunneling microscopy. STM images reveal the presence of a 2x1-monohydride reconstruction for the untreated (100) surface and a lxl reconstruction for the untreated (111) surface. No other atomically resolved reconstructions were observed under a wide range of growth conditions. Non-aqueous electrochemical investigations were carried out on the films exhibiting atomically resolved reconstructions. Evidence for potential-induced surface-reconstruction and surface chemical modification of the (100) 2xl-monohydride surface has been observed.

Photoelectron Spectroscopy And The Dipole Approximation, Oliver Hemmers, Dennis W. Lindle

Environmental Studies Faculty Publications

Over the past three decades, the dipole approximation has facilitated a basic understanding of the photoionization process in atoms and molecules. Advances in gas-phase photoemission experiments using synchrotron radiation have recently highlighted nondipole effects at relatively low photon energies while probing the limits of the dipole approximation. Breakdowns in this approximation are manifested primarily as deviations from dipolar angular distributions of photoelectrons. Detailed new results demonstrate nondipolar angular-distribution effects are easily observable in atomic gases at energies well below 1 keV, and, in molecules, a previously unexpected phenomenon greatly enhances the breakdown of the dipole approximation just above the core-level …

Boron-Doped Homoepitaxial Diamond (100) Film Investigated By Scanning Tunneling Microscopy, Bing Xiao, Weihai Fu, Sacharia Albin, Jason Moulton, John Cooper

Electrical & Computer Engineering Faculty Publications

Conducting epitaxial diamond films of high quality are essential for many diamond studies and diamond electronic device fabrication. We have grown boron-doped epitaxial diamond films on type Ila natural diamond (100) substrates by microwave plasma chemical vapor deposition. A gas mixture of H₂/CH₄ was used. Boron doping was done by placing solid sources of pure boron in the microwave plasma. Homoepitaxial films with atomic smoothness were achieved under the following growth conditions: substrate temperature 900 °C, gas pressure 40 Torr, and gas flow rates of H₂/CH₄ = 900/7.2 seem. The growth rate was 0.87 …

The Difference Of The Geometrical Thickness And The Electrochemical Apparent Effective Thickness Of Self-Assembled Monolayers, Xiao-Li Cui, Jun-Xin Li, Ru-Ting Tong

Journal of Electrochemistry

The geometrical thickness, which was obtained from the capacitance of membrane, can be used to characterize the existence of membrane. The apparent effective thickness, which is analyzed from the electron transfer constant of transmembrane, can be used to determine the degree of “collapsed" of molecules. Though the two thicknesses were different in value, there was no contradiction. The influence on the geometrical thickness is little, but the effect to the apparent effective thickness is great from the small “collapsed" area in the membrane from the given calculation.

Electrochemical Hydrogen Storage Properties Of Carbon Nanotubes, Xue Qin, Xue-Ping Gao, Feng Wu, Hong Liu, Ying Lan, Hua-Tang Yuan, De-Ying Song, Pan-Wen Shen

Journal of Electrochemistry

The electrochemical properties of carbon nanotubes (CNTs) electrode have been investigated in this paper. The high discharge capacity of 200 mAh·g^-1 was measured for the CNTs Ni electrode at a discharge density of 200 mAh·g^-1 . CNTs-Ni electrode, the high electrochemical activity and the long cycle life were observed. The electrochemical mechanism of hydrogen adsorption and oxidation at the CNTs Ni electrode was studied by cyclic voltammertry method.

Fabrications And Characterizations Of Porous Silicon By Tow-Step Techniques I: Constant Current Application, Xuan Cheng, Feng-Ming Liu, Chang-Jian Lin, Zuo-Xin Wen, Zhong-Qun Tian, Ru Xue

Journal of Electrochemistry

Porous silicon structures were formed by a two step technique consisting of electrochemical polarization and chemical oxidation processes in 1∶1 hydrofluoric acid and ethanol solutions. A constant current density of 0.03 A/cm² was applied to p type silicon wafers, followed by chemical treatment in 20% nitric acid solutions. These samples were then carefully examined by scanning electron microscope (SEM) and Raman spectrometer to study their surface morphologies and optical properties. After a year storage in a desiccator, the aged porous silicon samples were re examined by SEM and Raman spectrometer before and after treated with styrene and decene(1) organic …

A Study Of Monitoring Corrosion Of Metal Via An Optic Waveguide Sensing Method, Xue-Ming Li, Wei-Ming Chen, Shang-Lian Huang, Na Zhang, Zong-Qing Huang

Journal of Electrochemistry

An optical wave guide sensing method was proposed for monitoring corrosion of metal in outdoors steel structures. Replacing the cladding of wave-guide with metal film in a particular location, the method takes the metal film as the corrosion sensitive film. The experiment of waveguide sensor was carried out on a 721 colorimetric vessel, with which the soution is held in itself and the light is propagated in its sidewall. A Fe-C alloy film was electroplated onto the inner sied of vessel to form the corrosion sensitive film. The structure of the Fe-C alloy film was studied by XRD, EDX and …

A Study Of The Adsorption Behaviors On The Surface Of Gold Electrode By In-Situ Electrochemical Raman Spectroscopy, Xia-Qin Wu, Xiao-Wei Cao, Zhe-Su Wang, Xiao-Yun Meng, Zong-Rang Zhang

Journal of Electrochemistry

The results of in-situ measurements with Raman spectroelectrochemical thchnique on bare gold electrode and adenine modified gold electrode were reported. The adsorption behaviors of adenine and superoxide dismutase (SOD) and their interactions with gold electrode were analyed. The mechanism of promoted electron transfer process of SOD in the presence of adenine at gold electrode surface is discussed.

Study On Electrodeposition Of Ingaas Thin Film, Yu-Chun Li, Xi-Lian Wang, Jing-Ke Han, Ai-Zhen Han, Yuan-Kai Gao, Zhi-Wei Yang

Journal of Electrochemistry

The principle and the experimental method of the electrodeposition are discribed in detail in this paper. InGaAs thin film was prepared by using optimized electrodeposited conditions. The radiative wave length of the film was between 1.3～1.5 μm, the composition of the film was analyzed by energy spectrometer and the transmission spectrum of the film was measured by spectrophotometer and monochromator. The V-I chractristic of the conductive type and the topography of the In_xGa_1-xAs film were also studied.

Effect Of High Concentration Lithium Bromide Solution On Electrochemical Behavior Of Low Alloy Steel At High Temperature, Jian-Wei Guo, Cheng-Hao Liang

Journal of Electrochemistry

By electrochemical measurements and weight loss experiments, the effect of MoO₄^2- on low alloy steel's electrochemical behaviors was investigated at high temperature in 55%LiBr+0.07 mol/L LiOH solution. The results showed that MoO₄^2-, as an anodic inhibitor, formed passive film rapidly and impeded both anodic and cathodic procedures. Moreover, Na₂MoO₄ prevented corrosion effectively in 55%LiBr+0.07 mol/L LiOH solution when its concentration is more than 200 mg/L. The pitting potential increased accompanying to the arising of Na₂MoO₄ concentration. Some elements of alloy strengthened resistance to corrosion, shch as chromium and nickel, …