Facile synthesis and enhanced photocatalytic activity of hierarchical porous ZnO microspheres

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.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Hierarchical porous ZnO microspheres were synthesized. ► ZnO spheres show enhanced photocatalytic activity for degradation methylene blue. ► The enhanced photocatalytic activity is attributed to the special structural feature. ► This synthesis route can be extended to the synthesis of other metal-oxide materials.