Confining Pd Nanoparticles and Atomically Dispersed Pd into Defective MoO Nanosheet for Enhancing Electro- and Photocatalytic Hydrogen Evolution Performances.

Interface engineering of two-dimensional (2D) transition-metal composites for activating plane and edge sites is a significant yet step challenging in boosting their performance for hydrogen evolution reaction (HER). Herein, two-dimensional (2D) MoO with petal-shaped nanosheets confining Pd nanoparticles (Pd@MoO heterostructure) was prepared via an efficient solvothermal and subsequently hydrogen reduction processes. The atomically dispersed Pd-substituted sites in the interface of Pd nanoparticles and 2D MoO lattices significantly play an important role in enhancing the electrocatalytic and photocatalytic performances of the Pd@MoO heterostructure. As a result, the Pd@MoO heterostructure exhibits a high HER catalytic activity with an overpotential (η) of 71 mV to achieve a current density of 10 mA cm and an extremely low Tafel slope of 42.8 mV dec in 0.5 M HSO solution. Furthermore, the photoresponse of the Pd@MoO heterostructure is about 3 times higher than that of the MoO nanosheets. This work highlighted a strategy of interface engineering for highly efficient cost-effective catalyst for hydrogen evolution by electric and solar energy conversion.