Exceptional Photochemical Interface: Creation of a p–n Junction and Enhanced Photoreduction Ability

The interface of substances at the photoexcited state is completely different from that at the ground state, which gives a chance to create some unprecedented physical and chemical properties. These interface-dominated properties can significantly improve carrier transport kinetics. Herein, we report a special photochemical strategy for constructing a heterogeneous interface. We synthesized a series of catalysts involving SnS2 and Zn2AgInS4 (ZAIS), providing an example of constructing a photochemical interface between n-type and p-type two-dimensional substances. Zeta potential confirmed that the photoinduced surface charge of ZAIS changed from negative to positive. This change in charge sign created the possibility of combining ZAIS with SnS2 carrying negative charges. First-principles calculations certified that the photochemical interface is thermodynamically feasible. Nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) data confirmed that the interface in the heterogeneous catalysts of ZAIS/SnS2 was formed during the photo-illumination process. Owing to the promoted fast separation of photogenerated carriers, the catalyst possessing a p–n junction photochemical interface exhibits optimal Cr­(VI) photoreduction and photocatalytic H2 evolution performance as well as good stability. Photochemistry provides a universal methodology for constructing exceptional interfaces and guiding the synthesis of interfacial functional materials.