Facet-selective photodeposition of gold nanoparticles on faceted ZnO crystals for visible light photocatalysis

Hexagonal prism-like ZnO crystals dominated with polar facets were synthesized using a hydrothermal method. The Gold (Au) nanoparticles were selectively photodeposited on the polar surfaces of faceted ZnO crystals as a result of anisotropic photocatalytic activities of the polar and nonpolar facets. The size of Au nanoparticles uniformly dispersed on the polar facets increased with increasing Au-loading amount. These Au-loaded ZnO crystals showed an additional visible light absorption band from 400 nm to 800 nm. The 0.1 wt% Au-loaded ZnO crystals with visible light absorption peak at approximately 690 nm exhibited the highest photocatalytic activity under visible light irradiation.