Interface Engineered W xC@WS2 Nanostructure for Enhanced Hydrogen Evolution Catalysis.

For increasing scalability and reducing cost, transition metal dichalcogenides-based electrocatalysts presently have been proposed as substitutes for noble metals to generate hydrogen, but these alternatives usually suffer from inferior performance. Here, a Ravenala leaf-like W xC@WS2 heterostructure is grown via carbonizing WS2 nanotubes, whose outer walls being partially unzipped along with the W x C 'leaf-valves' attached to the inner tubes during the carbonization process. This heterostructure exhibits a catalytic activity for hydrogen evolution reaction with low overpotential of 146 mV at 10 mA cm−2 and Tafel slope of 61 mV per decade, outperforming the performance of WS2 nanotubes and W xC counterparts under the same condition. Density functional theory calculations are performed to unravel the underlying mechanism, revealing that the charge distribution between W xC and WS2 plays a key role for promoting H atom adsorption and desorption kinetics simultaneously. This work not only provides a potential low-cost alternative for hydrogen generation but should be taken as a guide to optimize the catalyst structure and composition. [ABSTRACT FROM AUTHOR]