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.