Construction of visible light-driven p-BiOI/n-ZnSnO3 heterojunction and its application in photocatalysis

A simple template-free solvothermal method was employed to prepare ZnSnO 3 cubic structures loaded with BiOI nanosheets. The composition, morphology, microstructure, and physicochemical properties were characterized using XRD, SEM, and UV–vis spectroscopy. The effect of the solvents, reaction times, temperature, and the molar ratio of Bi to Sn on the morphology, structure, and performance of the samples was systematically investigated. With the increase in the molar ratio of Bi to Sn, the band gap of the composite decreases from 3.24 to 1.95 eV and then increases to 1.97 eV. The photocatalytic properties of the as-obtained samples were studied in detail. The photocatalytic activity of the typical sample (B 3 Z 7 ) was about 7.64 times higher than that of the pure ZnSnO 3 sample, which should be attributed to their enhanced light absorption, small band gap, and distinctive morphology and structure. The electrochemical impedance spectroscopy and photocurrent density test show that the heterostructure can promote the charge transfer and separation efficiency of the photogenerated carriers in the as-synthesized composite sample.