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

Abstract

AbstractDeveloping 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 H2O molecules on the Mo and Co sites and accelerating water dissociation. Therefore, NiCoCu‐Mo0.078/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‐Mo0.078/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‐Mo0/CF and NiCoCu‐Mo0.163/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.