ISSN:0005-9021    

DOI:10.1002/bbpc.198800295

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1988

数据来源: WILEY

摘要:

AbstractA survey is given of the various ways in which information on the structure of electrode surfaces and their influence on the electrochemical behavior, especially on adsorption reactions, can be obtained. The techniques now at hand include a wide variety of spectroscopic methods, which are applicable in‐situ, such as reflectance spectroscopy over a broad range of photon energy, second harmonic generation, various X‐ray diffraction techniques and, most recently, scanning tunneling microscopy, which highlights the possibility of acquiring atomic‐scale resolution. In addition, the emersion of electrodes and their subsequent transfer into a vacuum chamber for detailed surface‐structural studies, e.g., by electron diffraction methods, is now widely used in electrochemistry, since it has been shown that electrodes can, in fact, be emersed with their electric double layer apparently intact. The combined venture incorporating all these techniques should lead to a truly microscopic description of electrochemical processes. The way in which structural information, even on an atomic scale, can be derived, is illustrated here by a few selected e

ISSN:0005-9021    

DOI:10.1002/bbpc.198800296

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1988

数据来源: WILEY

摘要:

AbstractThe principles of the design of integrated chemical systems based on semiconductor materials for the photoelectrochemical utilization of solar energy to drive useful chemical reactions are described. The use of different support materials, such as Nafion and silica, to prepare particulate systems is discussed. Systems with very small (“Q‐”) particles are described. Charging of these particles is proposed as an important factor in the determination of particle energetics (optical band gap and potentials of photogenerated electrons and holes). Semiconductor arrays, with a number of junctions in series to provide higher driving potentials, are discussed, and two systems for the photosplitting of water to hydrogen and oxygen are desc

ISSN:0005-9021    

DOI:10.1002/bbpc.198800297

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1988

数据来源: WILEY

摘要:

AbstractElectrochemical multiphase systems of industrial importance may be divided into dispersed three‐dimensional electrodes, gas evolving electrodes, conversion of gaseous reactants and electrochemical extraction systems. The engineering fundamentals of all these types developed by several groups during the recent years will be summarized. Additionally new electrochemical techniques for studying non‐electrochemical unit operations like absorption and extraction will be introdu

ISSN:0005-9021    

DOI:10.1002/bbpc.198800298

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1988

数据来源: WILEY

摘要:

AbstractRecent progress in the theory of the electric double layer at a metal/solution interface is reviewed. In the absence of specific adsorption the system may be represented as jellium in contact with an ensemble of hard sphere ions and dipoles; results of explicit model calculations are compared with experimental data. When ions are specifically adsorbed, the induced change in the surface dipole potential is of particular interest. Due to the effective screening of the adsorbate charge by the solvent and by the metal electrons, the corresponding dipole moments are relatively small. Finally, isotherms for ionic adsorption are considered in the limit of vanishing bulk concentration.

ISSN:0005-9021    

DOI:10.1002/bbpc.198800299

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1988

数据来源: WILEY

摘要:

AbstractThe adsorbate formed during ethanol oxidation in acidic solutions is studied by Fourier transform infrared reflection‐absorption spectroscopy (FTIR) at constant potential, on‐line (DEMS) and thermal desorption mass spectroscopy (ECTDMS). – As in the case of methanol adsorbate COadwas identified by FTIR and in addition COHadby ECTDMS. On‐line MS experiments showed the formation of methane during the cathodic sweep of the voltammogram. Main products of ethanol oxidation from the bulk are carbon dioxide and aceta

ISSN:0005-9021    

DOI:10.1002/bbpc.198800300

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1988

数据来源: WILEY

摘要:

AbstractThe theory for the calculation of changes of mass and surface stress from frequency measurements at a quartz oscillator subject to different onesided pressures is outlined. The various contributions to apparent changes of the mass are discussed. Experiments refer to the determination of effective molar masses of potassium ions and fluoride ions during electrostatic adsorption and of chemisorbed lead both on polycrystalline gold by a comparison of masses to charges. Effective molar masses of adsorbed species can also be determined by comparison of mass changes to surface concentrations e.g. determined by the radiotracer method as in the example of the adsorption of chloride at the passivating oxide film on iron. The density of very thin films like the passivating oxide film can be obtained by comparing mass changes to thicknesses from optical measurements. In agreement with theoretical expectation, compressive surface stresses were qualitatively found for the underpotential deposition of lead on gold. In the growing oxide film on passive iron very large compressive lateral pressures were observed.

ISSN:0005-9021    

DOI:10.1002/bbpc.198800301

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1988

数据来源: WILEY

摘要:

AbstractThe synthesis and characterization of [(methoxycarbonyl)methyl]‐cobalamin1dis reported. Cyclic voltammetry of1din DMSO at a Hg‐electrode shows two irreversible cathodic waves corresponding to the reduction of the base‐off and base‐on forms of1d. At sweep rates lower than 0.5 V/s, only reduction of the base‐off form is observed (Ep(off) = −0.954 V vs SCE at 0.1 V/s). At sweep rates faster than 10 V/s, reduction of the base‐on form prevails (Ep(on) = −1.422 V vs SCE at 10 V/s). The thermodynamic and kinetic parameters of the base‐off/base‐on equilibrium of1din DMSO are estimated. Two electrons are involved in the reduction of1din 0.1 M CH3COOH/DMF. In the absence of a proton source, one‐electron reduction predominates. B12sis a sufficiently strong reducing agent to induce reducti

ISSN:0005-9021    

DOI:10.1002/bbpc.198800302

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1988

数据来源: WILEY

摘要:

AbstractThe mechanism of the anodic dimerization of olefins is investigated with the rotating ring‐disc‐electrode. The anodic coupling is applied to the preparation of a morphine derivative. By cathodic addition of organo halides to aldehydes trichloromethylcarbinols, β‐hydroxyesters and cyclopentanoid hydrocarbons become acce

ISSN:0005-9021    

DOI:10.1002/bbpc.198800303

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1988

数据来源: WILEY

摘要:

AbstractThe corrosion behavior of carbon steel in weakly acidic NaCl solutions which were aerated or deaerated by H2or CO2has been studied in the temperature range 298 K ≥T≥ 343 K depending on the rotation frequency of RDE and the exposure time using conventional corrosion test methods and electrochemical impedance spectroscopy (EIS). Based on different theoretical transfer functions, the EIS data were analyzed with nonlinear fit procedures. It is shown that this method can be succesfully applied for an efficient and rapid screening of about 150 organic inhibitors for oil and gas product

ISSN:0005-9021    

DOI:10.1002/bbpc.198800304

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1988

数据来源: WILEY