High photocatalytic performance of ZnGa2O4/Ga2O3 double-shell hollow sphere structures prepared via a one-step hydrothermal method†

In this study, photocatalytic degradation of rhodamine B (RhB) using one-step hydrothermally prepared ZnGa₂O₄/Ga₂O₃ heterojunctions with double-shell hollow sphere structures was investigated. It was found that this structure greatly improved the photocatalytic performance through the formation of an S-scheme heterojunction at the interface between ZnGa₂O₄ and Ga₂O₃. By optimizing the feed ratio, a maximum RhB degradation rate of 0.1133 min⁻¹ was obtained, which was nearly 2 times higher than that of the Ga₂O₃ monomer photocatalyst, 5 times higher than that of the ZnGa₂O₄ monomer photocatalyst, and 96 times higher than the RhB self-degradation rate. Capture experiments showed that h⁺ played a key role in the efficient decomposition of RhB reactive groups. This study provides a new idea and a simple preparation method for the novel ZnGa₂O₄/Ga₂O₃ S-scheme heterojunctions for efficient photocatalytic degradation of organic pollutants.