Effect of Native Defects on Photocatalytic Properties of ZnO

We have studied the photocatalytic activity of ZnO tetrapods, ZnO powder, and different ZnO nanoparticles. While nanoparticles with small particle size exhibited higher Brunauer-Emmett-Teller (BET) surface area, tetrapods exhibited significantly higher photocatalytic activity for degradation of different dyes. Degradation of four different dyes has been achieved for at least 5 times shorter time for tetrapods compared to nanoparticles (20 nm average particle size). Different ZnO samples have been characterized by variable-temperature photoluminescence and time-resolved photoluminescence measurements, and the relationship between optical properties, native defects, production of the reactive oxygen species, and photocatalytic dye degradation has been discussed.