Theoretical explorations of hydrogen evolution reaction mechanisms in transition metal-doped intermetallic compounds

Intermetallic compounds (IMCs) have emerged as promising catalysts for the hydrogen evolution reaction (HER). However, the mechanisms regarding their electronic modulations and the atomic-scale principles governing active site selection still remain insufficiently understood. In this study, we have employed density functional theory (DFT) calculations to investigate L1₂-type IMCs composed of noble metals (Rh, Pd, Ir, Pt) with 3d/4d/5d transition metals (TMs) for HER. By constructing 145 periodic superlattice IMC models, we have systematically explored the influences of metal–metal interactions on catalytic performance through d-d coupling interactions, revealing the origin of the characteristic volcano-shaped trend in hydrogen adsorption free energy (ΔGH). Our calculations show that 70.9% of optimal active sites are dominated by noble atoms, while the introduced TMs primarily serve as electronic modulators. Furthermore, we have identified 14 potential HER catalysts with optimal ΔGH and good thermal stability. The d-band center theory predictions show deviations of ΔGH when d-band centers of TMs lie above the Fermi level. This work provides key theoretical insights to understand the HER processes on IMCs, guiding the design and synthesis of high-performance IMC catalysts.