排序方式: 共有44条查询结果,搜索用时 15 毫秒
31.
32.
The potentiodynamic response of cobalt in KOH solutions (10?2M?c?2.5 M) in the potential range of the thermodynamic stability of the Co(II) species reveals two limiting electrochemical behavirours. One of them corresponds to the first potentiodynamic scan and the other is associated with the stabilized E/I profile resulting after a prolonged potential scanning. The former is related to the large contribution of the metal electrodissolution process. The second is explained in terms of reactions taking place at the sandwich-type structured interface. Ageing effects of Co(II) surface species are also considered in the interpretation of results. 相似文献
33.
34.
Pasquale MA Saracco GP Marchiano SL Arvia AJ 《The journal of physical chemistry. B》2005,109(43):20256-20265
The formation of silver patterns via electrolysis from aqueous silver sulfate + x% w/v agarose sol and gel media, with and without supporting electrolyte, in a quasi-two-dimensional (2D) cylindrical cell at room temperature, is utilized as a reference system to investigate the complexity of pinning effects. From pattern morphology and electrochemical data, both delocalized and localized pinning in the bulk dominate the drift of the growth front, depending on the concentration of agarose in the heterogeneous media. Delocalized pinning results from mobile, small agarose aggregates at the growth front and from their accumulation by the front drift. For gels, localized pinning comes from their own percolated structure. A depinning/pinning transition is observed in going from sols to gels. The relative contribution of diffusion and advection in mass-transport-controlled silver electrodeposition depends on the plating bath composition. On the other hand, silver ion attachment to the cathode appears to be interfered with by some screening caused by weakly adsorbed, mobile agarose aggregates at the metal surface without slowing down the rate of the electron-transfer step at the cathode. Their relative contribution of a delocalized, localized pinning and screening effect to a great extent determines the morphology and transition in the growth mode of silver patterns in both media. The analysis of charge and current transients and the corresponding silver pattern morphologies for open and dense radial patterns is made. Results are qualitatively simulated with a novel, rather simple cellular automaton algorithm. 相似文献
35.
M.L. Marcos J. Gonzlez-Velasco J.M. Vara M.C. Giordano A.J. Arvia 《Journal of Electroanalytical Chemistry》1989,270(1-2)
The electrooxidation of “reduced CO2” electroadsorbates on electrodispersed platinum electrodes has been investigated in 0.05 M HClO4, 1 M HClO4, 0.5 M H2SO4 and 1 M H3PO4 at 25° C through voltammetry and potential step techniques. The overall reaction comprises three distinguishable processes, namely a first order triggering process, and two second order surface processes. The latter are influenced remarkably by the solution composition (anions). The second order reaction mechanism involves two distinguishable “ reduced CO2” electroadsorbates which react independently with the OH species formed from H2O electrooxidation on the bare platinum sites as the reaction proceeds. An interaction term has to be included in the rate equations to account for the experimental results. The mechanistic interpretation accounts for the values of the number of electrons per site ranging from 1 to 2. 相似文献
36.
37.
38.
39.
E. Pastor S. Wasmus T. Iwasita M.C. Arvalo S. Gonzlez A.J. Arvia 《Journal of Electroanalytical Chemistry》1993,350(1-2)
The electrochemical behavior of n-propanol (n-PrOH) on polycrystalline Pt in acid solutions was investigated using in situ Fourier transform infrared spectroscopy (FTIRS) and on line differential electrochemical mass spectrometry (DEMS). The main products of n-PrOH oxidation are CO2, propanal and propionic acid. Different types of adsorbates with one, two or three C atoms were detected. Ethane and propane are produced from n-PrOH adsorbates during potential cycling in the H-adatom potential region. An increase in the quantity of adsorbed CO was observed after hydrogenation of n-PrOH adsorbates. 相似文献
40.