Evaluation of Au nanosphere content on ZnO nanoparticle surfaces as reusable and durable plasmonic nanocatalysts

Abstract

AbstractBACKGROUNDAu/ZnO systems have been investigated in recent years as alternatives to improve the photocatalytic performance obtained by pure ZnO and other nanocatalysts based on ZnO nanostructures. ZnO nanoparticles and Au/ZnO nanocatalysts were successfully synthesized by facile and low‐cost methods, such hydrothermal synthesis and chemical reduction method, respectively. The plasmonic nanocatalysts were fabricated at different Au precursor (HAuCl4) concentrations (0.5–5 mM) to obtain different Au contents (0.31–13.9 at.%) on the ZnO surface. The influence of Au content on the ZnO surface and its photocatalytic activity was studied.RESULTSThe photocatalytic activities of pure ZnO and Au/ZnO nanocatalysts were evaluated in the photodegradation of methylene blue (MB) solution under UV light. The Au/ZnO nanocatalyst with the lowest Au content (0.31 at.%) showed the best photocatalytic performance, reaching an MB degradation rate of 99.99% within 60 min (an enhancement of 60% compared with ZnO nanoparticles) and a reaction rate constant of 4.186 min−1 (×10−2), which is higher than those of other novel and complex nanocatalysts based on ZnO. Moreover, five cycles of self‐cleaning and an outstanding durability of 25 aging months were obtained during photocatalytic applications.CONCLUSIONAs demonstrated, a high amount of Au nanospheres on the ZnO surface is not necessary to enhance its photocatalytic activity. This synthesis process offers the possibility of obtaining the optimum amount of Au loading over the ZnO surface to reach a better photocatalytic performance, good self‐cleaning ability, and outstanding durability in comparison with other complex and recently reported catalysts (composites based on ZnO nanostructures). © 2023 Society of Chemical Industry (SCI).