Tiny NiP nanoparticles dispersed was used as an inexpensive, stable, and active cocatalysts on ultrathin Nb₂O₅ nanosheets to replace the noble metal Pt. Owing to the extended light harvesting, enhanced carrier separation, and improved surface reaction, the NiP/Nb₂O₅ exhibits even higher activity and selectivity towards CO₂ photocatalytic reduction. And the roles and function mechanisms of the cocatalyst were studied.

Abstract

Photocatalytic CO₂ reduction holds great promise to solve energy shortage and global warming. Nb₂O₅ has demonstrated superiority in CO₂ activation and selectivity regulation, but suffers from poor light absorption ability and fast carrier recombination. To tackle these problems, we designed and synthesized ultrathin Nb₂O₅ nanosheets which were decorated with tiny NiP nanoparticles as cocatalyst. In this way, light absorption range broadened, carrier migration distance reduced, charge transfer resistance decreased, and surface reaction kinetics promoted. Consequently, the as-prepared NiP/Nb₂O₅ showed notably enhanced activity (148.7 μmol ⋅ g⁻¹) and selectivity (82.1 %) towards CO, as well as remarkable stability. This work paves the way for cheap and earth abundant alternatives as cocatalysts and deepens the understanding of their functions in CO₂ photoreduction.