Comprehensive strategy through regulating specific atomic orbitals of electrocatalytic sites by heteronuclear...

Developing cost-effective transition metal sulfides (TMS) electrocatalysts as alternatives to noble metals for hydrogen evolution reaction (HER) remains a formidable challenge. For TMS, HER primarily occurs at sulfur (S) sites, making it difficult to improve electrocatalytic efficiency based solely on the conventionally single p/d-band center principle. Herein, we propose an integrated strategy that combines heteronuclear double-atom doping to regulate specific p-orbitals of S atoms via density functional theory (DFT) calculations, machine learning (ML) and experimental verification to efficiently identify high-performance electrocatalysts. Based on DFT calculations and ML analysis, we establish multidimensional predictive descriptors that incorporate the orbital characteristics of both active sites and coordinating atoms, identifying CuNi-Co₃S₄ as a promising electrocatalytic candidate. The results reveal that heteronuclear double-atom doping modifies the electronic distribution of Co₃S₄ and elevates p_y-orbital energies of S atoms, thereby promoting the HER activity. Guided by these findings, CuNi-Co₃S₄ was synthesized via coordination coprecipitation followed by hydrothermal sulfidation, and its excellent practical HER performance was experimentally confirmed. In alkaline solution with 1 M KOH, the resulting CuNi-Co₃S₄ electrocatalysts exhibit the outstanding activity with low overpotential (135 ± 3 mV) and small Tafel slope (81 ± 3 mV·dec^-1) at 10 mA·cm^-2, along with the remarkable stability exceeding 180 h. This work validates a highly integrated strategy for designing efficient noble-metal-free electrocatalysts, advancing the potential for industrial-scale green hydrogen production.