Atomically tailoring synergistic active centers on molybdenum sulfide basal planes for alkaline hydrogen generation

Abstract

Alkaline water electrolysis allows the adoption of non-precious metal catalysts, but increases the challenge of cathodic hydrogen evolution reaction (HER) with the proton-deficient environment. Here we report an “all-in-one” design by atomic-level tailoring on molybdenum sulfide (MoS₂) basal planes with synergistic active centers to trigger water dissociation for proton supply and meanwhile improve proton adsorption for hydrogen evolution. The resultant Co/O-codoped MoS₂ (Co-O@MoS₂) catalyst shows superb alkaline HER activity with a small Tafel slope of 42 mV dec^–1 and an overpotential as low as 81 mV at 100 mA cm^–2, and considerable stability over 300 h even at industrial-grade high current density of 600 mA cm^–2, which are among the best records for precious-metal-free HER catalysts in alkaline media. The markedly enhanced alkaline HER performance is attributed to the synergistic effect from atomically constructed O-Co-S₂ motifs with local electronic interactions, in which Co sites promote the premier water dissociation, and S sites facilitate proton transition to generate hydrogen, respectively. This work presents an atomic-scale structural modification to create synergistic active sites for alkaline HER and provides insights into the atomic activation engineering towards advanced catalysts.