Electron spin polarization-mediated charge separation in Pd/CoP@CoNiP superstructures toward optimized photocatalytic performance

Electron spin polarization plays a vital role on photocatalysis but rarely considered. Herein, a double-layer hollow yolk-shell Pd/CoP@CoNiP superstructure photocatalyst is prepared via two ion exchanges approach using Co-MOF as a template. It shows ferromagnetic characteristics and obvious photothermal effect due to the special structure. Interestingly, the photocatalytic hydrogen evolution is enhanced about twice under external magnetic field compared to field-free. The improvement can be ascribed to the enhanced electron spin polarization of the vacancy defects for Pd/CoP@CoNiP superstructure and the formation of Z-scheme heterojunctions promoting efficient photogenerated charge separation and prolonging the lifetimes obviously. The special double-layer hollow yolk-shell superstructure is another reason for the optimized photocatalytic performance, which could expose adequate surface active sites for photocatalytic reaction. Moreover, the high stability of this defective Pd/CoP@CoNiP superstructure indicates the potential applications in field of photocatalysis. This strategy may provide new insights for fabricating high-efficient superstructure photocatalysts with electron spin polarization.