Oxygen-facilitated dynamic active-site generation on strained MoS2 during photo-catalytic hydrogen evolution

Molybdenum disulfide (MoS2) is considered as one of the most effective materials which can supersede the high cost and scarcity of metal platinum (Pt) for the hydrogen evolution reaction (HER). One road block lying in access to high catalytic performance of MoS2 emanates from the inert basal plane. To enable inert basal plane of flexible MoS2, we demonstrate an effective synthesis strategy via the progressive transformation of MoS2 to MoS2-xOx with O atomically dispersed under actual photo-catalytic hydrogen evolution condition. The rate of hydrogen production of new reconstructed MoS2-xOx nanosheets is improved to be much higher than that of the initial MoS2. Our theoretical calculation results indicate that the appropriate O substitution and strain could modulate the surface electronic state and optimize the Gibbs free energy (ΔGH) of MoS2, thus dramatically accelerating the catalytic efficiency. This work showcases a promising route to achieve tunable photochemical reconstruction by optimizing the electronic structure for low-cost and robust MoS2-based HER catalysts.