Eco-friendly preparation of hierarchically self-assembly porous ZnO nanosheets for enhanced photocatalytic performance

In this work, wasted biomass pomelo peels (PPs) were chosen as template to prepare a series of ZnO nanomaterials via a simple two-step dipping/adsorbing-calcining strategy without adding any other additives, especially alkali precipitant. The morphology of the as-obtained ZnO can be tuned by controlling the amount of PPs, which transforms from stacked nanoparticles to hierarchically porous nanosheets. When evaluated as photocatalysts for methylene blue (MB) degradation under a 300 W high pressure Hg lamp (HPHL), the hierarchically porous ZnO nanosheets show much improved photocatalytic performance than those of stacked samples. The reason could be mainly ascribed to its special morphology, which is beneficial for efficient uptake of irradiating light, adsorption and activation of dye molecules, and separation of photo-generated electron-hole pairs. This work will shed light on the reuse of waste biomasses in photocatalysis field.