High-Performance Photocatalytic Degradation—A ZnO Nanocomposite Co-Doped with Gd: A Systematic Study

This research aims to analyze the improvement in the photocatalytic properties of ZnO nanoparticles by incorporating Gd. In order to understand the influence of incorporating Gd into the ZnO matrix, the photocatalytic activity of the material is compared at various Gd concentrations. Different doping concentrations of Gd ranging from 0 to 0.075 are incorporated into ZnO and the synthesized ZnO-Gd nanocomposites are investigated using structural, morphological, and optical analyses using XRD, SEM, and UV-vis spectroscopy, respectively. The photocatalytic performance of the synthesized ZnO-Gd nanocomposites is determined via the degradation of organic contaminants under visible light. Regarding the latter, the results suggest that photocatalytic efficiency increases with increasing Gd doping levels up to an optimal doping concentration. The enhancement of the photocatalytic performance of Gd-doped ZnO is explained, along with the mechanism related to the availability of new pathways for charge carrier recombination. Among all of them, the 0.075 Gd-doped ZnO catalyst exhibits the highest photocatalytic activity which degrades 89% of MB dye after being irradiated with UV light for 120 min. However, pure ZnO degrades only 40% of MB dye within the same testing conditions. In closing, this work confirms the applicability of Gd-doped ZnO nanocomposites as photocatalysts in cleaning up the environment and in wastewater treatment.