Enhanced Solar-Driven Applications of ZnO@Ag Patchy Nanoparticles

Abstract

ZnO@Ag patchy nanostructures were demonstrated to be efficient and stable photocatalysts for the photodegradation of organic contaminants in aqueous solutions. The photoinduced charge transfer from the conduction band of ZnO toward the Fermi level of the noble metal was favored and exploited to enhance the photocatalytic efficiency of ZnO, with a mechanism based on hole stabilization. Naked ZnO and ZnO@Ag patchy nanostructures were demonstrated to degrade methylene blue, a model compound, in aqueous solution under 370–800 nm light irradiation (100 mW cm–2); in particular, the introduction of silver nanoparticles allowed one to increment twice the constant rate of the reaction when fitted as pseudo-first-order kinetics. Furthermore, the degradation of 2,4-dichlorophenol under direct sunlight irradiation was studied. The photo-oxidation catalyzed by patchy nanostructures was noticeably increased. In fact, the observed half time (t1/2) was reduced by almost 4 times in comparison with the value observed for b...