Fine tuning of the face orientation of ZnO crystals to optimize their photocatalytic activity

The face-tunable synthesis of nano and microscale ZnO crystals with different ratios of polar to nonpolar faces is investigated. ZnO has a direct wide bandgap, that makes it very important for the photocatalytic generation of hydrogen peroxide, which can be utilized for the degeneration of organic pollutants and the sterilization of bacteria and viruses. As the photocatalytic reaction occurs at the interface between catalyst surfaces and organic pollutants, a strong dependency of photocatalytic activity on a specific crystal plane is demonstrated. The morphologies of the ZnO crystals were investigated with the help if field-emission scanning electron microscopy (FESEM). Soft-solution processes has been used to synthesized nanorods, nanoplates, and DB micropores of ZnO with different ratios of polar to nonpolar faces. The results shows that ZnO nanoplates with a high population of polar Zn (0001) faces show the highest photocatalytic activity for H₂O₂ generation.