Polyoxo-titanium clusters promoted photocatalytic H2 evolution activity in a NiS modified CdS/MIL-101 system

Abstract In this work, a new strategy is developed to design and synthesize quaternary catalysts NiS/CdS/MIL-101/PTCs (MIL = Materials of Institute Lavoisier, PTCs = polyoxo-titanium clusters) with excellent photocatalytic activity for H2 evolution. PTCs and NiS can be successfully integrated into CdS/MIL-101 system by multi-step solvothermal in situ reaction method. The as-synthesized photocatalysts integrated with NiS and PTCs exhibit the dramatically enhanced photocatalytic activity for hydrogen evolution, which is approximately 230 times higher than that of uncoupled catalyst CdS/MIL-101. It is more interesting that the photocatalytic activity can be tuned by structural evolution of PTCs. The photoelectrochemical characteristics of catalysts confirm that the drastic enhancement for photocatalytic H2-production activity was predominantly attributed to PTCs and NiS contributing to matching energy gap and improving visible-light response, respectively, and both inhibiting recombination of photogenerated electron-hole pairs. More importantly, this work can flourish the design idea derived from the relation of structure and application for photocatalysts.