The impact of nano-milling on porous ZnO prepared from layered zinc hydroxide nitrate and zinc hydroxide carbonate

Abstract The preparation of ZnO nanoparticles with a multi-step process is reported. The preparation path included zinc hydroxide nitrate (ZnHN) or zinc hydroxide carbonate (ZnHC) precipitation, their thermal treatment and nano-milling. ZnO preparation was followed in detail by STEM, FT-IR, XRD and TG-MS analyses. In order to demonstrate the efficiency of the nano-milling process, the obtained ZnO nanoparticles were characterized with regard to their photo-catalytic activity of caffeine degradation. The smallest ZnO nanoparticles (∼20 nm) with the highest BET surface (∼80 m 2  g −1 ) were prepared from ZnHC at 300 °C.