A surface-engineered Si photocathode with synergistic Ni-graphene core-shell for efficient hydrogen evolution

When designing photoelectrochemical cells with highly efficient and durable Si photocathodes, it is desirable to develop stable and active catalysts that enhance the charge carrier dynamics in the photocathode. Thus, we report the fabrication of a nickel-graphene core-shell catalyst through thermal chemical vapor deposition and its application to an Si photocathode for photoelectrochemical water splitting. The obtained nickel-graphene core-shell catalyst is composed of nickel particles as the core and a high-quality graphene monolayer as the shell. The synergistic effect between nickel and graphene in the core-shell structure could promote the photocarrier transfer process within the system. Thus, the as-prepared p-Si/Ni-Gr core-shell photocathode exhibits excellent PEC performance and durability with a high photocurrent density of −48 mA cm −2 at −1.2 V ( vs. RHE) over 50 hours. The strategy of adopting this novel catalyst provides a new approach for improving photocatalytic hydrogen production. A surface-engineered Si photocathode with a Ni-graphene core-shell structure is designed to enhance hydrogen evolution performance for water-splitting applications.