A Novel SnO2/ZnFe2O4 Magnetic Photocatalyst with Excellent Photocatalytic Performance in Rhodamine B Removal

In this study, we prepared the SnO2/ZnFe2O4 (SZ) composite magnetic photocatalyst via a two-step hydrothermal method. Structural and performance analyses revealed that SZ-5 with a ZnFe2O4 mass ratio of 5% (SZ-5) exhibited optimal photocatalytic activity, achieving a 72.6% degradation rate of Rhodamine B (RhB) solution within 120 min. SZ-5 consisted of irregular nano blocks of SnO2 combined with spherical nanoparticles of ZnFe2O4, with a saturated magnetization intensity of 1.27 emu/g. Moreover, the specific surface area of SnO2 loaded with ZnFe2O4 increased, resulting in a decreased forbidden bandwidth and expanded light absorption range. The construction of a Z-type heterojunction structure between SnO2 and ZnFe2O4 facilitated the migration of photogenerated charges, reduced the recombination rate of electron-hole pairs, and enhanced electrical conductivity. During the photocatalytic reaction, RhB was degraded by·OH, O2−, and h+, in which O2− played a major role.