Activity Descriptors for Atomically Precise HER Electrocatalysts

In electrochemistry, the hydrogen evolution reaction (HER) ranks among the most significant reactions. HER is the easiest method to produce very pure hydrogen so the development of effective HER catalysts is of great importance. This situation has significantly influenced many researchers in the field of electrochemistry and made it the focus of active studies. In this direction, many catalysts with different structures have been developed for HER over many years. Among the various HER catalysts, atomically precise electrocatalysts (single-atom, dual-atom, and multi-atom) are becoming more popular because of their efficient use of atoms and impressive electrocatalytic performance. Recently, researchers have made significant efforts to synthesize and develop atomically precise HER catalysts with high activity and stability. However, it is critical to descriptor new strategies to improve catalytic activity. Therefore, different descriptors have been developed to describe the correlation between catalyst morphology and activity. In this chapter, we summarized the activity descriptors commonly used in the design of atomically precise HER catalysts and their importance. We also discussed their impact on performance. Finally, strategies developed to identify new descriptors for promising HER catalysts are proposed.