ABSTRACT
This chapter explains the basic principles of electrocatalysis. The latter is a part of heterogeneous catalysis dealing with reactions, which occur at the electrified interface between the electronic and ionic conductors. It is noted that electrocatalysts are among the key functional materials for the devices used in hydrogen-involved energy provision schemes, namely electrolyzers and fuel cells. The origin of the differences between catalytic materials for alkaline and polymer electrolyte membrane electrolyzers is explained. The principles of designing electrocatalysts for energy applications are considered from the point of view of their activity, selectivity, and stability in fuel cells and electrolyzers. Sustainability factors are also briefly discussed.
