Zn:In(OH)ySz Solid Solution Nanoplates: Synthesis, Characterization, and Photocatalytic Mechanism

Zn:In(OH)ySz solid solution nanoplates (Zn:In(OH)ySz-SSNs) with uniform nanoparticle size were synthesized through a simple sodium dodecyl sulfate (SDS)-assisted hydrothermal process. To achieve better photoabsorption in the visible light (VL) region and suitable redox potentials of the Zn:In(OH)ySz solid solution (Zn:In(OH)ySz-SS), the substitution of S2− for OH− was carried out by adjusting the concentration of thiourea and SDS in the synthesis solution, while the doping of Zn2+ was realized by adjusting Zn2+ concentration. In addition, the morphology and crystallinity of Zn:In(OH)ySz-SSs were also controlled by the concentration of SDS. Using Rhodamine B (RhB) as a target pollutant, the photocatalytic performance of these Zn:In(OH)ySz-SSs with different components, diameter sizes, and morphologies was investigated. Remarkably, Zn:In(OH)ySz-SSNs prepared with atomic ratio of Zn2+ and In3+ of 0.6, 45 mmol L−1 thiourea, and 26 mmol L−1 SDS, have the highest visible-light-driven (VLD) photocatalytic activity, exceeding 95% for the degradation of RhB after 60 min. The investigation of photocatalytic mechanism further indicates that the holes, superoxide radical (·O2−) and surficial hydroxyl radical (·OHs) are the major reactive species for the photocatalytic reactions. More importantly, for the first time, a simple and versatile strategy is developed to confirm the fact that direct contact between the Zn:In(OH)ySz-SS and RhB is the prerequisite for the photocatalytic degradation of RhB. Therefore, we report not only the preparation of a novel and effective VL-driven photocatalyst, but also provide mechanistic insight into semiconductor photocatalysis.