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

Abstract

BackgroundAu/ZnO systems have been investigated in recent years as alternative 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 ZnO surface. The influence of Au content on ZnO surface and photocatalytic activity was studied.ResultsPhotocatalytic activity 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 a 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 (x10‐2) that is higher than other novel and complex nanocatalysts based on ZnO. Moreover, 5 cycles of self‐cleaning and outstanding durability of 25 aging months were obtained to progress in photocatalytic applications.ConclusionAs we demonstrate, it is not necessary high amount of Au nanospheres on ZnO surface for enhance the photocatalytic activity. Our synthesis process offers the possibility to obtain the optimum amount of Au loading over ZnO surface for reaching better photocatalytic performance, good self‐cleaning ability and outstanding durability in comparison with other complex and recently reported catalysts (composites based on ZnO nanostructures).This article is protected by copyright. All rights reserved.