Preparation of mesoporous nanosphere SiO2@TiO2 composite materials and the photocatalytic degradation performance of different dyes

Abstract

In this research, anatase-phase SiO₂@TiO₂ spherical photocatalysts were fabricated by the sol–gel method. Comprehensive characteization was performed through SEM, XRD, BET, XPS, PL, and UV-vis spectroscopy to elucidate the materials' morphology, crystal structure, composition, and optical properties. The photocatalytic performance was assessed through degradation rate of Rhodamine B (RhB). The catalyst annealed at 550 °C for 5 h exhibited exceptional activity and degraded 99.75% of RhB under UV light in 40 minutes, revealing a performance surpassing most literature reports. Notably, it retained over 83% efficiency after four cycles, attesting to its robust stability. Moreover, the annealing time exerted little effect on the photocatalytic activity of the photocatalyst. The free radical trapping experiment suggested that under visible light, hydroxyl radicals (˙OH) dominated RhB degradation, while holes (h⁺) and superoxide radicals (˙O₂⁻) contributed auxiliary roles. Furthermore, the impact of calcination parameters (temperature, duration), and catalyst addition amount, on the degradation of RhB, and the degradation ability of different pollutants was also systematically evaluated. These findings provide valuable insights for optimizing photocatalyst preparation and application.