Strain derived from bubbles at monolayer MoS2/hBN interfaces for enhanced hydrogen evolution reaction activity

Transition metal dichalcogenides (TMDs), notably monolayer MoS2, are promising catalysts for the hydrogen evolution reaction (HER) due to their versatile surface and tunable band gap. Despite efforts to enhance catalytic activity, the impact of out-of-plane microstructure remains overlooked. In this study, we investigate the enhancement effect of bubbles on HER activity by fabricating bubbles with different curvatures at the interfaces between monolayer MoS2 and hBN during a droplet-assisted transfer process. Bubbles induce the formation of strain on the MoS2, enhancing the adsorption of protons and HER kinetics and leading to an exponential increase in HER activity (129.65 mA cm−2 vs. 48.11 mA cm−2 at −0.4 V vs. RHE). Theoretical calculations reveal that the synergistic interaction of S vacancies and tensile strain can generate more gap states near the Fermi level and enhance the adsorption of hydrogen. Our findings provide an updated understanding of the relationship between out-of-plane microstructure and activity.