Construction of hierarchical nanostructured surface on an organic hybrid selenidostannate with light trapping effect to achieve sunlight-driven environmental remediation

Due to the low intensity of sunlight, it is a great challenge to realize highly efficient sunlight-driven photocatalysis. To maximize the utilization of sunlight, increasing the light capturing ability of photocatalysts is a prerequisite to attain high catalytic performances. Due to the multiple reflections of light in the hierarchical nanostructures, constructing hierarchical nanostructured surface should boost the sunlight capturing ability of a photocatalyst. Herein we used a surface oxidation etching method to construct a hierarchical nanostructure on the surface of an organic hybrid selenidostannate [Bmim]₄[Sn₉Se₂₀], namely BTSe. After 24 hours of etching by ammonium persulfate, the surface of BTSe-O24 turned into a hierarchical nanostructure. FDTD simulation proved that the hierarchical nanostructure can effectively decline the loss of incident light and enhance light capturing ability of BTSe-O24. As a result, BTSe-O24 can completely reduce Cr(VI) (100 mg/L) in 8 min with a conversion rate of 750 mg/(g h) under sunlight. The catalytic performance of BTSe-O24 under sunlight is even better than those of most reported photocatalysts under high-power xenon lamps. More importantly, BTSe-O24 can maintain high photocatalytic efficiency in the whole daytime (from 8:00 to 16:00 in autumn and winter). Our research opens a new perspective on the design of sunlight-driven photocatalysts.