Electrochemical models hydrogen evolution

Most metals (other than the alkali and alkaline-earth metals) are corrosion resistant when cathodically polarized to the potentials of hydrogen evolution, so that this reaction can be realized at many of them. It has thus been the subject of innumerable studies, and became the fundamental model in the development of current kinetic concepts for electrochemical reactions. Many of the principles... 

Medvedev IG. 2004. To a theory of electrocatalysis for the hydrogen evolution reaction The hydrogen chemisorption energy on the transition metal alloys within the Anderson-Newns model. Russ J Electrochem 40 1123-1131. 

Other model reactants are simple organic molecules, for example, formic acid [381, 382]. Pt(lll) exerts lower catalytic influence on HCOOH oxidation than do Pt(lOO) and Pt(llO) faces. However, in the presence of Pb adatoms on Pt(lll) a strong catalytic influence has been observed [383]. The poisonous species production in HCOOH oxidation is then inhibited. Electrochemical reduction of CO2 to glycolate/glyoxylate and oxalic acid has been studied [384]. Other products such as formic acid accompanied by CO and methane have also been detected [385]. In the latter case, the efficiency of the competing process of hydrogen evolution has been suppressed to less than 3.5%. 

The second item that needs to be fixed is the number of species and the reactions, including the stoichiometric coefficients and also the kinetics of the processes. In this context, in electrochemical oxidation processes it is important to discern between two types of anodes those that behaves only as electrons sinks (named nonactive) and those that suffer changes during the electrochemical oxidation which influence on the treatment (named active electrodes). In both cases, the main processes related to removal of the pollutant that involves irreversible oxidative routes. Consequently, the reductive processes are less important and it can be presumed that in the cathodic zone only hydrogen evolution occurs. Nevertheless, if some organic compound can be reduced at the cathode, the mass-transfer and the reduction processes must be included in the model scheme. 

In electrochemical proton transfer, such as may occur as a primary step in the hydrogen evolution reaction (h.e.r.) or as a secondary, followup step in organic electrode reactions or O2 reduction, the possibility exists that nonclassical transfer of the H particle may occur by quantum-mechanical tunneling. In homogeneous proton transfer reactions, the consequences of this possibility were investigated quantitatively by Bernal and Fowler and Bell, while Bawn and Ogden examined the H/D kinetic isotope effect that would arise, albeit on the basis of a primitive model, in electrochemical proton discharge and transfer in the h.e.r. 

Skulason E, Tripkovic V, Bjorketun ME, et al. Modeling the Electrochemical Hydrogen Oxidation and Evolution Reactions on the Basis of Density Functional Theory Calculations. J Phys Chem C. 2010 114 18182-97. 

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