Edge-Contact Geometry and Anion-Deficit Construction for Activating Ultrathin MoS2 on W17O47 in the Hydrogen Evolution Reaction.

Abstract

Rational design and precise fabrication of catalysts with high active site exposure and efficient charge transport are highly desirable but challenging. Herein, we report a unique strategy to construct well-defined and mixed-dimensional W17O47-MoS2 heterostructures, where ultrathin MoS2 nanolayers vertically rooted onto W17O47 nanowires in edge-contact geometry. The in situ etching approach simultaneously created high accessible anion-deficit sites for refined electronic structures and intimate heterointerface for spatial charge-flow-steering. The best W17O47-MoS2, with optimized MoS2 loading, exhibited a MoS2 mass activity 116-fold higher than that of pure MoS2 in electrocatalytic hydrogen evolution reaction. Density functional theory calculations unveiled that low-coordination sites and intimate interfaces induced the synergy of interface-O and edge-Mo atoms, substantially regulating the electron distribution of active sites in the critical hydrogen activation step. This work not only provided a platform for understanding the origin of catalytic activity, but also brought instructive design criteria for constructing heterostructures in catalysis, photonics, and electronics.