Table 1.

Some representative theoretical descriptors used for HER

Descriptor	Category	Trend of catalytic activity	Applicable
ΔG H*	Electronic descriptor	ΔG H* < 0 a relatively strong H molecule binding ability; ΔG H* > 0 a relatively weak H molecule binding ability	All catalysts
d‐band center theory	Electronic descriptor	Downward/upward shift of the d‐band center weakening/enhancing the metal‐H bond strength	Metal and metal alloy/oxide
Valence band theory	Electronic descriptor	Increase/decrease of the filling of the bonding states enhancing/weakening the metal–H bond strength	Nonmetallic carbon materials
Ionic electronegativity regional electronegativity φ	Electronic descriptor	AIE—activity volcano plot Ψ—ΔG H* volcano plot	Cobalt‐based perovskites transition metal disulfide
Generalized coordination number	Structural descriptor	GCN—activity volcano plot	Metals and metal alloys single‐atom electrocatalysts