Wrinkle facilitated hydrogen evolution reaction of vacancy-defected transition metal dichalcogenide monolayers

Utilizing transition metal dichalcogenides (TMDs) as catalysts in hydrogen evolution reaction (HER) exhibits a promising prospect for hydrogen production. Here by first-principles calculations we reveal that the catalytic activities of vacancy-defected TMD MX2 (M = Mo or W, and X = S, Se or Te) monolayers for HER can be significantly improved by wrinkle engineering. The hydrogen adsorption Gibbs free energies of defected TMDs decrease with decreasing the wrinkle length. By appropriately controlling and adjusting wrinkle size and vacancy number, the hydrogen adsorption Gibbs free energy will be close to zero, making wrinkled TMDs reach the optimum catalytic capability. The improvement of catalytic activity of TMDs is mainly attributed to the charge transfer and polarization enhancement of metal atoms at the vacancy sites, which are caused by the coupling effect of vacancy defects and wrinkling deformation induced flexoelectricity. These results provide an attractive route by combining wrinkle engineering and defect engineering for the application of TMDs in hydrogen production.