New insight into an efficient visible light-driven photocatalytic organic transformation over CdS/TiO₂ photocatalysts

Selective transformation of organics by visible-light-driven photocatalysis has been considered as a green and efficient strategy for the synthesis of fine chemicals. Herein, we fabricated mesoporous structured TiO₂ with CdS nanoparticles successfully by a photodeposition method. The photocatalytic selective oxidation of benzyl alcohols and reduction of 4-nitroaniline were demonstrated over the as-prepared samples under visible-light irradiation. The CdS-decorated TiO₂ with the photodeposition time of 90 min exhibited highest activity, which was higher than that of the commercial CdS, bare TiO₂, CdS/P25, and CdS/SiO₂. Further experimental results indicated that the higher performance was attributed to the moderate deposition of CdS forming a closely connected heterojunction with TiO₂, which promoted the separation of photogenerated electrons and holes. Based on the results of active species detection, possible mechanisms for photocatalytic selective oxidation of benzyl alcohol and reduction of 4-nitroaniline were proposed. Our study may provide guidance for selective transformation of organics via construction of heterojunction photocatalysts.