Electrocatalysis

electrocatalysis [i‚lek·trō·kə′tal·ə·səs]

(chemistry)

Any one of the mechanisms which produce a speeding up of half-cell reactions at electrode surfaces.

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Electrocatalysis 

the change in the rate and selectivity of electrochemical reactions achieved by means of the catalytic action of electrodes, upon whose surfaces these reactions occur.

Electrocatalysis was first observed at the beginning of the 20th century, when the dependence of the rate of the cathodic evolution of hydrogen on the electrode material was established in a series of studies. However, it became widespread only after 1960, mainly in connection with investigations related to fuel cells. Electrocatalysis is closely related to the adsorption of the reactants, intermediate products, and final products of a reaction.

The major problem in the theory of electrocatalysis is the explanation of the nature and prediction of the catalytic activity of various electrode materials. The concept of electrocatalysis is sometimes also extended to the study of adsorption and other physicochemical properties of the surface of various catalysts by electrochemical methods and to the study of the kinetics and mechanism of the electrochemical steps in catalytic processes in solutions—liquid-phase reduction or oxidation. In some cases, these processes are reduced to coupled electrochemical reactions, such as the cathodic reduction of a hydrogenated compound and the anodic oxidation of hydrogen.

Electrocatalysis is of great importance in improving the operating efficiency of chemical sources of current and electrolyzers. In many cases, electrodes coated with platinum catalysts are used in these devices to accelerate the electrochemical processes. A problem of practical importance in electrocatalysis is the development of less expensive and more available catalysts using metallic and nonmetallic materials with high electrocatalytic activity, including oxides and organic semiconductors.

V. S. BAGOTSKII