Strategies for Tuning Tensile Strain and Localized Electrons in a Mo-Doped NiCoCu Alloy for Enhancing Ampere-Level Current Density HER Performance

Developing high-activity non-noble metal catalysts for improving the ability of water dissociation and H* adsorption/desorption in the hydrogen evolution reaction (HER) process in alkaline and neutral electrolytes is essential but remains challenging. Herein, a Mo-doped NiCoCu alloy with tuned tensile strain and localized electrons is designed and synthesized by combining the solvothermal and annealing methods for achieving ampere-level HER performance. Theoretical calculation results prove that Mo doping induces lattice tensile strain and localized electrons (electrons from Mo to the Ni/Co/Cu atoms), promoting the adsorption of O* and H* from H 2 O molecules on the Mo and Co sites and accelerating water dissociation. Therefore, NiCoCu-Mo 0.078 /CF (CF = copper foam) shows low water dissociation energy, providing sufficient H* during the HER process. Meanwhile, its H* Gibbs free energy value is near zero, implying a rapid H* adsorption/desorption process. Electrochemical results show that NiCoCu-Mo 0.078 /CF achieves better HER intrinsic activity in both a 1.0 m KOH ( η −10 /η −1000 = 35/212 mV) and a 1.0 m phosphate buffer solution ( η −10 /η −1000 = 24/256 mV) compared to NiCoCu-Mo 0 /CF and NiCoCu-Mo 0.163 /CF, and it can continuously operate for 100 h at −1000 mA cm −2 . This work shows a sustainable way to design high-performance catalysts for water electrolysis and proposes a well-performing HER catalyst.