Visible-light-sensitive nanoscale Au-ZnO photocatalysts

摘要

The role of gold nanoparticles supported on ZnO in photocatalytic activity for dye degradation was investigated. To this end, gold nanoparticles supported on ZnO (Au-ZnO) were prepared using a simple co-precipitation method. The prepared nanocatalyst was characterized by high-resolution transmission electron microscopy, X-ray diffraction, temperature-programmed reduction, X-ray photoelectron spectroscopy, UV-Vis absorption, and photoluminescence. The photocatalytic activity of Au-ZnO was examined by the degradation of methylene blue in aqueous solution using a light source that has more than 95 (i.e., energy) of emitted photons between 400 and 800 nm. Highly enhanced photocatalytic degradation of methylene blue in air at room temperature was observed from these Au-ZnO nanocatalysts with gold particle size ranging from 2 to 7 nm, with an average size of 3.8 nm. The observed rate constant for MB degradation on Au-ZnO was 0.0118/min compared with 0.0007/min for pure ZnO. Furthermore, the charge transfer pathway for the degradation of methylene blue in Au-ZnO is suggested.