Exceptional\nPhotochemical Interface: Creation of a\np–n Junction and Enhanced Photoreduction Ability

The\ninterface of substances at the photoexcited state is completely\ndifferent from that at the ground state, which gives a chance to create\nsome unprecedented physical and chemical properties. These interface-dominated\nproperties can significantly improve carrier transport kinetics. Herein,\nwe report a special photochemical strategy for constructing a heterogeneous\ninterface. We synthesized a series of catalysts involving SnS<sub>2</sub> and Zn<sub>2</sub>AgInS<sub>4</sub> (ZAIS), providing an\nexample of constructing a photochemical interface between n-type and\np-type two-dimensional substances. Zeta potential confirmed that the\nphotoinduced surface charge of ZAIS changed from negative to positive.\nThis change in charge sign created the possibility of combining ZAIS\nwith SnS<sub>2</sub> carrying negative charges. First-principles calculations\ncertified that the photochemical interface is thermodynamically feasible.\nNuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy\n(XPS) data confirmed that the interface in the heterogeneous catalysts\nof ZAIS/SnS<sub>2</sub> was formed during the photo-illumination process.\nOwing to the promoted fast separation of photogenerated carriers,\nthe catalyst possessing a p–n junction photochemical interface\nexhibits optimal Cr(VI) photoreduction and photocatalytic H<sub>2</sub> evolution performance as well as good stability. Photochemistry\nprovides a universal methodology for constructing exceptional interfaces\nand guiding the synthesis of interfacial functional materials.