Facile synthesis and enhanced photocatalytic activity of hierarchical porous ZnO microspheres

Abstract In this paper, hierarchical porous ZnO microspheres were successfully synthesized by calcining the microspheric zinc hydroxide carbonate (ZHC) precursor, which were the precipitate products of a hydrothermal reaction by zinc nitrate hexahydrate and urea in the presence of trisodium citrate. The as-prepared ZnO microspheres with diameters of 4–5 μm were assembled by numerous porous nanosheets which had the uniform thickness of about 10 nm. The photocatalytic activity of the ZnO microspheres was evaluated by photodegradation reaction of methylene blue (MB). The as-prepared ZnO microspheres exhibited a significantly enhanced photocatalytic activity than commercial ZnO and TiO2. This was mainly attributed to the larger specific surface area and stability against aggregation.