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.