Physical Chemistry Commons^™

The Effect Of Some Ions On Cr2O72- Anodic Formation Process At Pt And Pbo2 Electrodes, Shixiong Jin, Zhigang Zhou, Lan Wang

Journal of Electrochemistry

The influence of Ag₂SO₄, Li₂SO₄, Na₂SO₄, K₂SO₄, (NH₄)₂SO₄,MgSO₄ and KF on the evolution of O₂ and the formation of Cr₂O at Pt and PbO₂ anodes was investigated in mixed H₂SO₄-Cr₂(SO₂)₃ solutions. The kinetic data related respectively to Cr₂O formation and O₂ evolution at Pt and PbO₂ anodes were measured by method of resolving the steady-state polarization curve. The Tafel slope …

A Investigation Of Hydrogen-Storage Alloy As Catalytic Electrode For Hydrogenation Of Nitrobenzene, Shigang Lu, Hanxi Yang, Changfa Wan

Journal of Electrochemistry

Since hydrogen-storage alloy ean not only absorb hydrogen atoms to form highlyreactive metal hydride as hydrogen source by electrolysis but also possesses a certain catalytic activityfor hydrogenation,it is thus feasible to utilize the allov as a novel electrode for electrolvtichydrogenation in organic electroreduction. This work employed misch metal AB₅ type alloy as acatalytic electrode and studied the electrochemical hydrogenation of nitrobenzene.

The hydrogen-storage electrode (MH) was a plastic bonded electrode sheet made from a paste of Mm(NiCoMnAl)₅ alloy powder and teflon emulsion. The electrolysis was performed at constantcurrent and controlled potential in a three electrode cell of H-type …

Synthesis Of LiXCoo2 And Its Behaviour In Rechargeable Lithium Battery, Mingfeng Guo, Ruimin Yang, Zebo Zhang, Jincao Ye

Journal of Electrochemistry

The Variations of crystal lattice parameters of Li_xCoO₂ during charge anddischarge have been st ud ied by XRD and AAR spectroscopy. It was found that the Li_xCoO₂ crystalvolume expanded during charge and contracted during discharge. The crystal lattice structure was broken because of the formation of Co₃O₄ when deeply charge.The variation of lattice parameter C₀ value in cycling process was similar to that in charge process.The variation of 006 peak was the mostsensitive in every case. In case of preheating for 20 hours at 700℃ before operating high temperature, the …

Atomic And Molecular-Perspectives In Electrochemical Interfaces, Zhaowu Tian

Journal of Electrochemistry

The following recent studies on the atomic and molecular-perspectives at electrochemical interfaces using Raman, IR, STM and quantum chemical methed by electrochemistry group in Xiamen University are briefly reviewed. 1.Orientation, charge transfer and bonding of adsorbed molecules. 2. Adsorption effect, electrode potential effect and adatom effect on the electron populations and strength of intramolec ular bonds of the adsorbed molecules. 3. Detailed classification into various types (e. g., competitive, chemically inductive, physical inductive etc.) of coadsorption on electrodes according to the above-mentioned effects.  4. Single crystal face structure effect and adatom effect on the kinetics and the mechanisms of electrocatalytic …

Transient Photocurrent Behavior Of Multiple Quantum Well Gaas/AlXGa(1-X)As Electrode, Liu Yao, Xurui Xiao, Yuan Lin, Yiping Zeng, Dianzhao Sun, Haiqun Zheng

Journal of Electrochemistry

Transient photocurrents induced by short light pulses at lattice-matched multiplequantum well (MQW)GaAs/Al_0.3)Ga_0.7 As electrodes were studied in the 1 ×10^-2 mol·dm^-3 ferrocene([Fc⁰]/[Fc⁺]=9/1)-0.1 mol·dm^-3 tetrabutylammonium tetrafluoroborate acetonitrile solutionin order to examine the relaxation photoprocesses and to evaluate kinetic parameters of superlattice electrodes.

GaAs/Al_0.3Ca_0.7 As MQW electrode consisting of 10 periods with each of GaAs well (5.3 nm) and Al_0.3Ga_0.7. As barrier (10 nm) showed two pronounced and well-resolved peak structures located at 1.503 eV and 1.699 eV in the photocurrent spectrum, corresponding to the …

Self Assembly Via Layer By Layer Surface Reaction On Gold Electrodes And The Electrochcmical Characterization, Xiandui Dong, Juntao Lu, Chuanxin Cha

Journal of Electrochemistry

The self-assembled monolayers,which were built by spontaneous adsorption of ω-carboxylic acid thiols on gold surface,were used as substrate for further modification through later bylayer amide surface reactions. At each stage of modification,the gold surface was characterizedelectochemieally. The results demonstrated that the strategies of layer by layer self assembly is ofsignificant potential for fabrieating functionalized ultrathin layers.

Electroreduction Of The Nittobenzene On Titanium Electrode Implanted With Palladium, Zhongda Wu, Xianjun Zhu, Hongsen Wang

Journal of Electrochemistry

The titanium substrates were bombarded with 1×10¹⁷～5×10¹⁷ ions·cm^-2 ofpalladium at the room temperature. The surface composition of implanted electrode and concentration-depth profiles of various elements were measured by AES. The electrored uction processes ofnitrobenzene (NB) in 0.1 mol/L NaOH solution at Pd/Ti electrodes have been investigated by cyclicvoltaivimetry. The results show that the palladium implanted titanium electrodes exhibit a high catalyticactivity in the electroreduction of NB. The NB radical anion, which is the product of one-electronelectroreduction of NB, was detected by ESR in-situ in conjunction with electrochemical methods. Aniline was also detected as a product of …

Electroreduction Of Holmium Ion On Iron Electrde In Molten Cholorides, Qiqin Yang, Guankun Liu, Yuzhi Su

Journal of Electrochemistry

The cyclic voltammetry, open circuit potential-time curve after poteritiostatic electrolysis, current-time curve at potential step, X-ray diffraction and electron probe microanalysiswere used to investigate the electrode process of Ho(Ⅲ) reduced on iron electrode in molten chloridesand the phases of surface alloy layer. The Ho-Fe alloys are formed at first, and then the metallic holmium is deposited when Ho(Ⅲ) is reduced on iron electrode. The charge transfer is reversible. The free energies of formation for the four inter metallic compounds of Ho-Fe system, the diffusion coefficients and diffusion activation energy of Ho in alloyed cathode are determined.

Study Of Electrochemical Properties Of Ni(Oh)2/Niooh With Spectroscopic Ellipsometry, Shengtao Zhang, Zongqing Huang

Journal of Electrochemistry

Electrochemical reactions of Ni(OH)₂ /NiOOH system were studied by using in-situ spectroscopic ellipsometry and the conventional electrochemical metheds. By fitting data from ellipsometric measurements, a transformation medel of the surface film was obtained for cathedic and anodic processes. The results indicated that the transformation medel after cobalt implantation almost remained the same as that before cobalt implantation, but the electrochemical properties were affected obviously by implantation of cobalt.

Electrocatalytic Oxidation Of Formaidehyde And Formic Acid On A Pt/SbAd Electrode, Hong Li, Lincai Jiang, Xiong Jiang

Journal of Electrochemistry

The electrocatalytic activity for the oxidation of formaldehyde and formic acid ona Sb-modified platinum (Pt/Sb_ad) was investigated. Results showed that the Pt/Sb_ad electrode was electrocatalytically more active than a Pt electrode in the anodic oxidation of formaldehyde and formicacid. In the case of formaldehyde, an oxidation peak appeared at a potential of ca. 0.7V. During the oxidation of formic acid, a 4-fold increase in the 1st peak current was observed. The Sb-modified platinum electrode was found to be most electrocatalytically active at a coverage of 0.75±0.05. The electrocatalytic activity of the Pt/Sb_ad electrode can be best …

The Study Of The Growth Processes Of The Oxides On Lead Electrodes In Sulfuric Acid Solution, Hesheng Zhai, Xuguang Chen, Jinkua You, Yong Yang, Zugeng Lin

Journal of Electrochemistry

The growth processes of PbO and PbO₂ on lead electrodes have been investigatedby using in-situ methods that are combined with temporary AC resistance measurment technique and in-situ laser scanning photoelectrochemical microscopy. It is found that a linear relationship existsbetween the electrode resistance(R) and^1/2 after the electrode is oxidized at +0.6 V(vs.Hg/H₂SO₄/35% H₂SO₄) for more than 5 min. This result suggests that the growth of PbO is well distributed during the early stage of oxidation. The study by using laser scanning photoelectrochemical microscopy has further proved this point. The results also …

Application Of Voltammetry In Analysis Of Electroplating Baths, Jiayuan Xu, Shaomin Zhou

Journal of Electrochemistry

Based upon the electrochemical characteristics of the components or impurities tobe determined in the electroplating baths, and the inhibition or activation effect of the additives used on the electrodepcosition processes of metals and alloys, direct voltammetry, indirect voltammetry andvoltammetry with anodic stripping of metallic deposits, were suggested to determine the concentrationof some components, several impurities and the additives usually used in the electroplating baths. The procedure of those methtods are simple and rapid ,and are suitable to be used for in-situ control in electroplating workshops.

The Electrode Process Of Y(Ⅲ) On Copper Electrode And Its Surface Metallizing, Chungen Zhou, Shuzhen Duan

Journal of Electrochemistry

The reduction of yttrium ion on copper electrode in NaCl-KCl-YCl₃ molten saltshas been investigated. The results indicate that the formation of intermetallic compounds is occuredbefore the metallic yttrium to be formed. The formation of intermetallic compounds is controlled bythe process of which yttrium atoms are diffusing into copper electrode. The kinetic characters todiffusion of yttrium atoms were also discussed.

The Catalytic Behavior For Ni-W Electrode Modified By Carbon Ion Beam Implantion, Jishuang Zhang, Yaojiao Lv, Qinglian Li, Baoen Shen

Journal of Electrochemistry

The hydrogen evolution activity in acidic and basic mediums for Ni-W electrodemodified by carbon ion bean implantation was investigated. The experimental results show thiselectrode has superior catalytic activity for the hydrogen evolution reaction than that of the unmodified Ni-electrode. Long period testing of electrolysis under high current density show that this electrode hasalonger useful life hence it is a practical electrode material. The temperature effect of electrocatalytic property was also inverstigated. The experimental regularities are explained on the basis of the formation of surface multialloys of Ni-W-WC.

The Use Of Thermal Analysis In The Identification And Characterization Of Fibers Of Forensic Interest, Ronald J. Coffey

All-Inclusive List of Electronic Theses and Dissertations

This study investigates the use of thermal analysis for the identification and characterization of fibers for forensic purposes. Fibers such as polyesters, polyacrylics, polypropylenes and nylon were investigated by Differential Thermal Analysis (D.T.A.) and Thermogravimetric Analysis (T.G.A.) to see if their resulting thermograms were characteristic of each fiber. Also, infrared analysis was performed on each fiber. In addition, such factors as heating rate and sample size along with fiber blends were studied as to their effect on thermograms. As a result of this study several important conclusions may be drawn. Although it was found that for the most part D.T.A. …

On The Mechanism Of The Diels-Alder Reaction--Dimerization Of Trans-Phenylbutadiene, Michael Ward Mcnicholas

Dissertations and Theses

The Diels-Alder dimerization of trans-1-substituted butadienes is expected to yield a cyclohexene adduct with the substituents in the 3 and 4 positions cis to one another. This prediction is based on past observations of other Diels-Alder additions. The cis-isomer is the only one consistent with a two-stage mechanism proposed by Woodward and Katz.

In the case of trans-phenylbutadiene, the expected adduct is cis-3-phenyl 1-4-(trans-styry1) cyclohexene. Alder, Haydn and Vogt, however, reported that the corresponding trans-isomer is the dimerization product. There is reason to believe that the observation of the trans-isomer may have been the result of product isomerization during purification. …

Properties And Structure Of Some Chalcogenide Glasses, Amin Ismail Amin Abdel-Latif

Archived Theses and Dissertations

No abstract provided.

Determination Of Saponification Rate By Change In Hydrogen Ion Concentration Measured With Quinhydrone And Glass Electrodes, Richard Porter

Bachelors’ Theses

The measurement or hydrogen ion concentration is becoming more important in all the fields of chemistry since the states or many chemical systems can to some extent be defined by their hydrogen ion concentration. If the hydrogen ion concentration or a particular solution can be measured accurately, in many cases other important relations and quantities may be determined. Methods or measurement are therefore important instruments or investigation.

When an ester is saponified by an alkali, the hydrogen ion concentration increases as the reaction proceeds. Thus, it the hydrogen ion concentration can be calculated at different intervals of time, some knowledge …