Interplay of surface and subsurface contributions in electrocatalysis

Heterogeneous electrocatalysts stabilize adsorbed reaction intermediates at their surfaces and promote electron transfer to facilitate reaction rates. Although immense efforts—both experimentally and computationally—look to identify and understand the active site, many bulk descriptors have found utility in reactions such as the O₂ reduction and evolution and CO₂ reduction reactions. In parallel, studies modifying catalyst supports and other bulk parameters indicate a more complex picture in understanding heterogeneous electrocatalyst reactivity. Here we highlight the interplay between the subsurface and surface in electrocatalysis, including charge transfer, strain, and possible reconstruction of the active surface. These impacts illustrate the importance of considering not only the active site but also its surroundings in designing and understanding electrocatalysts.