Integrating RuNi alloy in S-doped defective carbon for efficient hydrogen evolution in both acidic and alkaline media

Abstract

• RuNi-alloy @ SC is prepared by desulfurization from bimetallic sulfide solid. • RuNi-alloy @ SC performs outstanding HER performance in wide pH range. • The S-doped defective carbon as a support further boosts the electron transfer. The preparation of alloy nanoparticles for hydrogen evolution reaction (HER) is a feasible strategy to optimize the inherent electronic structure of bimetallic catalysts, affording high catalytic activity. However, most of the metal alloys prepared currently exist in the form of bimetals, so it is urgent to find a facile method for preparing alloys. Herein, we developed a facile process by desulfurization from bimetallic sulfide solid solution for effectively constructing an electrocatalyst of RuNi alloy implanted with S-doped defective carbon (RuNi-alloy @ SC), which performs outstanding HER performance in both acidic and alkaline solutions. As expected, the optimized catalyst displayed quite a low overpotential of 34 mV at current density of 10 mA cm −2 , small Tafel slope of 55 mV dec −1 , and long-term durability over 120 h for HER operation in acidic solution. In alkaline medium, the low overpotential and Tafel slope of 93 mV and 96 mV dec −1 were further achieved. Density functional theory (DFT) simulations reveal the hydrogen adsorption free energy (ΔG H* ) of RuNi alloy with different crystal faces, in which RuNi (1 0 3) face enables the lowest ΔG H* for HER, whose value equals to that of the Pt. This work provides an advanced method and novel insights into the design of alloy electrocatalyst for HER.