Electronic reconfiguration and multistage mass transfer synergistically boost wide-pH, high-efficiency hydrogen evolution on Zn–MoC

Abstract

The adaptability of hydrogen evolution reactions over a wide pH range is significantly limited due to insufficient active sites and slow charge transport. In this work, a Zn-doped porous molybdenum carbide catalyst (Zn–MoC) was designed with a graphitic carbon layer and a graded porous structure using high-temperature calcination. Experimental and theoretical calculations showed that Zn doping could effectively modulate the electronic structure of MoC, synergistically optimize the adsorption/dissociation kinetics of water molecules and weaken the Mo–H bond strength to enhance the intrinsic activity. The porous skeleton and the conductive graphitic carbon layer exposed abundant active sites and significantly accelerated the charge transfer process. The catalyst can reach a current density of 100 mA cm⁻² in both acidic and alkaline electrolytes with overpotentials of only 279 mV and 315 mV, which are superior to those of most transition metal-based catalysts. The catalyst can be operated stably for more than 140 h. This study provides a new electronic structure and structure modulation strategy for the design of wide-pH-adaptable and low-cost HER catalysts.