Controllable preparation and photocatalytic activity of hierarchical flower-like microspheres clustered by ZnO porous nanosheets

The zinc carbonate hydroxide hydrate was prepared by the hydrolysis reaction between zinc nitrate and urea at 90 ? for 12 h. Then, the hierarchical flower-like microspheres clustered by ZnO porous nanosheets are obtained by calcination of precursor zinc carbonate hydroxide hydrate without structure deformation. The ZnO porous nanosheets were characterized by XRD, TEM, SEM, BET, UV-Vis absorption, photocurrent, impedance and fluorescence emission decay. The average pore size can be controlled from 11.77 to 49.53 nm with the calci-nation temperature increased from 300 to 500 ?. The ZnO porous nanosheets show well photocatalytic activity for degradation of crystal violet. Besides, the ZnO porous nanosheets calcined at 400 ? exhibit the highest photodegradation rate, due to the highest separation efficiency of photogenerated charge carriers with the highest photocurrent, the lowest migration resistance and the longest fluorescence emission decay lifetime.

Automated summary

In this study, zinc carbonate hydroxide hydrate was prepared through the hydrolysis reaction between zinc nitrate and urea, and hierarchical flower-like microspheres composed of porous ZnO nanosheets were obtained by calcination. The calcination temperature can control the average pore size, and ZnO porous nanosheets calcined at 400℃ showed the highest photodegradation rate.