Constructing dual-cocatalyst-directed quantifiable electron and hole transfer for enhanced photocatalytic performance

Photocatalysts are essential for the preparation of wanted fine chemical and biomedical intermediates via visible photocatalysis, but existing photocatalysts with low catalytic efficiency limit their wide applications. Herein, CdS/Ti₃C₂T_x/MBI nanocomposites have been successfully fabricated through anchoring reduction cocatalyst Ti₃C₂T_x with electron-drawing ability and oxidation cocatalyst 2-mercaptobenzimidazole (MBI) with hole-capturing capacity on CdS nanoparticles. The Ti₃C₂T_x and MBI of CdS/Ti₃C₂T_x/MBI nanocomposites can extract electrons and holes from CdS nanoparticles to come true electron-hole separation, respectively. Moreover, the electron-drawing and hole-capturing abilities of the CdS/Ti₃C₂T_x/MBI nanocomposites depend on Ti₃C₂T_x and MBI contents, and the quantifiable electron and hole transfers finally determine photocatalytic efficiency of the CdS/Ti₃C₂T_x/MBI nanocomposites. The transient photocurrent density of the CdS/Ti₃C₂T_x/MBI nanocomposites is 6-fold higher than that of the CdS nanoparticles. The CdS/Ti₃C₂T_x/MBI nanocomposites with strong electron-hole separation capability exhibit outstanding visible photocatalytic organic transformation properties. The CdS/Ti₃C₂T_x/MBI nanocomposites produce (E)-N-benzyl-1-phenylmethylimine in ~96% yield (~8000 μmol·g^–1·h^–1), which is 3-fold higher than the CdS nanoparticles (~2500 μmol·g^–1·h^–1, 30%). This work provides a new strategy for constructing efficient and stable photocatalysts that can be used for efficient visible light-driven organic transformations.