ZnO/CeO.sub.2 nanocomposite with low photocatalytic activity as efficient UV filters

In this study, we successfully synthesized ZnO/CeO.sub.2 composite nanoparticles for efficient ultraviolet (UV) filtering applications using a simple precipitation route. Various ratios of Ce/Ti, 2.5 at.%, 5 at.%, and 10 at.% were used to precipitate ceria onto commercial ZnO nanopowder at pH 9. The calculated mean crystallite sizes of the resultant nanocomposites were ~ 90 nm, ~ 79 nm, and ~ 41 nm for the 2.5 at.%, 5 at.% and 10 at.% ceria amounts, respectively. A stronger and more selective absorbance within the UV range was observed due to precipitation of a small amount of ceria to decorate the commercial ZnO surface. The photocatalyst results show that the addition of ceria, particularly with the precipitation amount increased up to 10 at.%, can effectively reduce crystal violet degradation by about 97% in a period of time from 0 to 30 min when exposed to ultraviolet light over 30 min or by around 99% under solar simulation for 30 min.