Fabrication of Type II heterojunction in ZnIn2S4@ZnO photocatalyst for efficient oxidative coupling of Benzylamine under visible light

A series of ZnxInySz was synthesized by hydrothermal method, and the corresponding ZnxInySz@ZnO composites with the internal type II heterojunctions were prepared by solvent assisted interface. It could be observed in SEM and TEM images of ZnIn2S4@ZnO that ZnIn2S4 present a petal-like sphere composed of nanosheets with nano fragments of ZnO attached on its surface. The results of fluorescence spectra and electrochemical impedance spectroscopy indicated that the formation of type II heterojunctions within ZnIn2S4@ZnO composites significantly promoted the separation of photocarriers. Therefore, ZnIn2S4@ZnO delivered excellent catalyticperformance for oxidative coupling of benzylamine. Under visible-light irradiation of 2 h, the conversion of benzylamine is as high as 96%, and the catalytic performance is still very steady after several cycles. It has not been reported that such a high conversion can be achieved in such a short period of time. Another advantage is that the coupling reaction does not require additional oxygen atmosphere and can be carried out in air condition, endowing this process with the feature of easier to be operated. This work provids an effective method for oxidative coupling of benzylamine through environmentally friendly way. This work provided an effective method for coupling of benzylamine environmentally friendly way.