Boosting alkaline hydrogen evolution via in-plane heterostructure construction with Ultra-Exposed heterointerfaces

Enhancing the catalytic efficiency of molybdenum disulfide (MoS2) towards the hydrogen evolution reaction (HER) is valuable for water electrolysis technology. This study fabricated a novel Co2P@1T-MoS2 "in-plane" heterostructure as a catalyst for alkaline HER. In this heterostructure, the Co2P nanoclusters are dispersed within the 1 T-MoS2 nanosheet. Remarkably, the coexistence of Co2P and 1 T-MoS2 phases within the same plane maximizes the exposure of interfacial active sites. The interfacial interaction between Co2P and 1 T-MoS2 facilitates water dissociation and hydrogen adsorption. This results in outstanding catalytic activity with a small overpotential of 37 mV at a current density of 10 mA cm(-2) in 1.0 M KOH. Intriguingly, the Co2P@1T-MoS2 heterostructure exhibits higher activity in alkaline electrolytes compared to acidic ones. The difference in active sites for hydrogen adsorption (Co versus S) in distinct electrolytes is believed to be the underlying reason for this "abnormality".