D-band frontier: A new hydrogen evolution reaction activity descriptor of Pt single-atom catalysts

Hydrogen evolution reaction (HER) is crucial for achieving sustainable development and carbon neutrality, and thus demands efficient catalysts, which necessitates fundamental theory to relieve trial-and-error experiment. To fast screen HER candidates, most studies focus on d-band center (εd) associated with the Gibbs energy of H* adsorption (ΔGH*). Unfortunately, εd rule is not applicable to Pt single atoms on transition metal disulfides (Pt1/TMDs) because of the additional contributions from p states of S atom. Here, we propose a new HER descriptor — d-band frontier (df) by defining the weight of d-band in the energy range of [−1.0 eV, 1.0 eV] of Pt single atoms. This df is exactly correlated with the ΔGH* of Pt1/TMDs, and thus perfectly describes the structure–activity relationship, as validated by systematical experimental evidences. Moreover, this df descriptor can be extended to Pt single atoms anchored on other supports (e.g., C3N4, C, MoO3, and CoO), indicating its promising generality.