Surface engineering of Au decorated V2O5 nanorods – Enhanced photodegradation of Rh-6G under visible light with high cyclability and stability

Abstract

The Au metal nanoparticles (NPs) decorated V2O5 (Au-V2O5) hetero-structured nanorods were prepared through a one step template-free hydrothermal method. Content of Au NPs in the Au-V2O5 was varied by controlling the amount of Au precursor. Structure, microstructure and optical properties of Au-V2O5 were studied by XRD, TEM, FE-SEM, UV–vis absorption spectroscopy and XPS analysis. Cubic structured Au NPs was found to decorate the surface of orthorhombic structured V2O5. Photo induced catalytic activity was investigated through degradation of Rhodamine-6 G (Rh-6G) dye under visible light irradiation. Higher degradation of Rh-6G dye was shown by Au-V2O5 photocatalysts when compared to pure V2O5. Photocatalytic mechanism for the process of Rh-6G degradation by Au-V2O5 is presented. The maximum degradation of 96 % was obtained by using the 1 wt% Au-V2O5 photocatalyst due to their optimum characteristics such as increased lifetime, increased reaction rate constant and half-life and reduced charge recombination. However, beyond 8 wt%, the Au NPs acted as charge trapping center and therefore lead to a decreased photocatalytic activity. The superoxide radicals (O2−) and electrons (e−) have been a major reactive species responsible for the enhanced photodegradation. The present work offers a novel route to reach higher photocatalytic activity by decorating the V2O5 nanorods with Au NPs. In particular, the 1Au-V2O5 hybrid nanostructured photocatalysts had exhibited an excellent photocatalytic activity, reproducibility, repeatability and long-term stability.