Biomass template induced hierarchically sponge-like Sn4+-doped ZnO for enhanced photocatalytic degradation of high concentration dye

Abstract

In this work, a series of hierarchically sponge-like Sn4+-doped ZnO materials were successfully fabricated by using biomass template-assisted hydrothermal and calcination strategies without adding any alkali precipitants. Their UV-photocatalytic activities were evaluated by degrading high concentration (50 mg/L) methylene blue (MB)-simulated waste water, and the influence of calcination temperature on photocatalytic performance were systematically investigated. Results show the degradation efficiencies of MB solution on all catalysts exceed 90% within 35 min, higher than pure ZnO material (86.93%). Particularly, the optimal Sn4+/ZnO-600 exhibits a high degradation efficiency up to 99.22%, while the Sn4+/ZnO-700 catalyst shows the lowest value of 91.20%. Also, the kinetic constants of all catalysts show a similar phenomenon to degradation efficiency. The improved photocatalytic performance may be ascribed to large surface area and doping-induced crystal defects that restrain fast recombination of photogenerated electron-hole pairs.