Construction of Ag2S@CdS p-n heterojunction for efficient visible light photocatalytic oxidative coupling of benzylamines to imines

Semiconductor photocatalytic organic reactions have garnered extensive interest owing to their environmentally friendly and sustainable advantages. Herein, the preparation of Ag2S@CdS p-n heterojunction through in-situ ion exchange reaction for photocatalytic benzylamine coupling is reported. Compared with pure CdS, Ag2S@CdS exhibited significantly enhanced photocatalytic activity for the oxidative coupling reaction of benzylamine. In particular, Ag2S@CdS showed high photocatalytic benzylamine conversion (>99 %) after 90 min under sunlight irradiation. The photocatalytic performance test at different wavelengths shows that the broadening of the light absorption range of Ag2S@CdS effectively improves the utilization of visible light. The photoelectric performance test demonstrates that the internal electric field of the p-n heterojunction effectively enhances the efficiency of separating photogenerated carriers. Moreover, Ag2S@CdS exhibited excellent compatibility with various benzylamine derivatives. The mechanism of photocatalytic benzylamine oxidation by Ag2S@CdS was investigated. This work provides some insights into the design of visible-light photocatalysts for selective organic synthesis.