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Manzhos R. A. Kotkin A. S. Kochergin V. K. Krivenko A. G. 《Russian Journal of Electrochemistry》2021,57(5):563-566
Russian Journal of Electrochemistry - Surface of boron-doped diamond film electrode was subjected to plasma-assisted electrochemical treatment by anodic plasma pulses, and a change in the rate... 相似文献
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Motivated by recent experimental observation (see, e.g., I. V. Rubtsov, Acc. Chem. Res. 42, 1385 (2009)) of vibrational energy transport in (CH2O) N and (CF2) N molecular chains (N = 4–12), in this paper we present and solve analytically a simple one dimensional model to describe theoretically these data. To mimic multiple conformations of the molecular chains, our model includes random off-diagonal couplings between neigh-boring sites. For the sake of simplicity, we assume Gaussian distribution with dispersion σ for these coupling matrix elements. Within the model we find that initially locally excited vibrational state can propagate along the chain. However, the propagation is neither ballistic nor diffusion like. The time T m for the first passage of the excitation along the chain, scales linearly with N in the agreement with the experimental data. Distribution of the excitation energies over the chain fragments (sites in the model) remains random, and the vibrational energy, transported to the chain end at t = T m is dramatically decreased when σ is larger than characteristic interlevel spacing in the chain vibrational spectrum. We do believe that the problem we have solved is not only of intellectual interest (or to rationalize mentioned above experimental data) but also of relevance to design optimal molecular wires providing fast energy transport in various chemical and biological reactions. 相似文献
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V. A. Kurmaz A. G. Krivenko A. P. Tomilov V. V. Turygin A. V. Khudenko N. N. Shalashova A. S. Kotkin 《Russian Journal of Electrochemistry》2000,36(3):308-315
To continue earlier investigations into the dimerization reaction during the cathodic cleavage of a carbon-halogen bond and,
in particular, to find an accessible way for synthesizing 1,4-butanediol, a comparative study of the dimerization of ethylene
halohydrins and butyl and allyl halides is performed. On the basis of the data obtained by the laser photoemission (LPE),
controlled-potential electrolysis, and voltammetry techniques, a general mechanism of the electrode reactions involving these
compounds and their intermediates is proposed and recommendations on the optimization of the 1,4-butanediol synthesis are
elaborated. According to LPE data, at pH < 8.1, the Β-hydroxyethyl radical reduction occurs with a preceding formation of
a complex with a proton donor, whereas a direct electron transfer is characteristic of the butyl radical. This difference
in mechanisms is offered as the main reason for the lesser capability of ethylene halohydrins to electrochemical dimerization
as compared with butyl halides, where the octane yield reached up to 80–84%. The earlier assumption about a high electrocatalytic
activity of the copper cathode in dimerization of ethylene halohydrins is confirmed, and possibilities of an iron cathode
in this process are revealed. The dimer yield is found to increase in alkaline solutions and at lowered temperatures, specifically,
at pH 11 and temperatures of 0–5°C., the 1,4-butanediol yield reached ∼17%. 相似文献
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Krivenko A. G. Kotkin A. S. Kurmaz V. A. Titov V. E. Lopushanskaya V. A. Koshechko V. G. 《Theoretical and Experimental Chemistry》2000,36(6):325-330
The redox potentials of the trifluoromethyl radical obtained experimentally by the laser photoelectron emission (LPE) method and by solution of the diffusion-kinetics problem involving the adsorption, desorption, electron transfer, and annihilation in the bulk of both the radicals and the products of their electrode reactions were compared. The usefulness of the LPE method for determining the redox potentials and rate constants of redox reactions of the CFmiddot
3 radicals was demonstrated. 相似文献
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Krivenko A. G. Manzhos R. A. Komarova N. S. Kotkin A. S. Kabachkov E. N. Shul’ga Yu. M. 《Russian Journal of Electrochemistry》2018,54(11):825-834
Russian Journal of Electrochemistry - A comparative study of electrochemical characteristics of graphite electrodes and precipitates of suspensions produced by the graphite exfoliation is carried... 相似文献
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A. G. Krivenko V. I. Matyushenko E. V. Stenina L. N. Sviridova A. V. Krestinin G. I. Zvereva E. R. Badamshina V. A. Kurmaz A. S. Kotkin G. V. Simbirtseva 《Russian Journal of Electrochemistry》2003,39(10):1137-1140
The differential capacitance and voltammograms of electrodes that contain single-walled carbon nanotubes are measured in aqueous electrolytes. The discovered dependence of the capacitance on the measurement frequency is attributed to structural features of nanomaterials used. Electrochemical characteristics of nanotube electrodes are close to those of glassy carbon electrodes, with the difference that the discharge current in the former is substantially higher at cathodic potentials in the presence of N2O. This effect is presumably caused by an autoelectron emission of electrons from nanotubes into electrolyte. 相似文献
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Krivenko A. G. Kotkin A. S. Kurmaz V. A. Simbirtseva G. V. 《Russian Journal of Electrochemistry》2003,39(7):760-768
Mechanism of reduction and oxidation of carboxymethyl and chlorocarboxymethyl radicals and ion-radicals adsorbed on a mercury electrode is studied by a laser photoemission method in broad ranges of potentials and solution pH. Versions of reduction and oxidation depend on the solutions" acid–base properties. In acid solutions, a metastable complex ion-radical–(radical)–proton donor undergoes reduction. In neutral and weakly alkaline solutions, the electron transfer onto an ion-radical dominates. In strongly alkaline solutions, a metastable complex ion-radical–proton donor undergoes reduction. The last complex is oxidized in neutral and alkaline solutions at anodic potentials, whereas in acid solutions carboxymethyl radicals and ion-radicals are oxidized. Kinetic parameters of metastable complexes barely depend on the presence of the chlorine atom in the radical, in contradistinction to the reduction overvoltage of ion-radicals and their complexes, which discernibly diminishes following halogenation. The experimental data are interpreted within an earlier model for electrode reactions involving intermediates, which includes two parallel channels for the electron transfer: adsorbed radical (anion-radical) to electrode and metastable complex radical (anion-radical) to donor/acceptor of protons to electrode. 相似文献