MoS-Stratified CdS-CuS Core-Shell Nanorods for Highly Efficient Photocatalytic Hydrogen Production.

Heterojunction photocatalysts are widely adopted for efficient water splitting, but ion migration can seriously threaten the stability of heterojunctions, as with the well-known low stability of CdS-CuS due to intrinsic Cu ion migration. Here, we utilize Cu migration to design a stratified CdS-CuS/MoS photocatalyst, in which Cu@MoS (Cu-intercalated within the MoS basal plane) is created by Cu migration and intercalation to the adjacent MoS surface. The epitaxial vertical growth of the Cu@MoS nanosheets on the surface of one-dimensional core-shell CdS-CuS nanorods forms catalytic and protective layers to simultaneously enhance catalytic activity and stability. Charge transfer is verified by kinetics measurements with femtosecond time-resolved transient absorption spectroscopy and direct mapping of the surface charge distribution with a scanning ion conductance microscope. This design strategy demonstrates the potential of utilizing hybridized surface layers as effective catalytic and protective interfaces for photocatalytic hydrogen production.