Tuning TiO 2 –SiO 2 Photocatalysts: Impact of Precursor Ratios and Synthesis pH on Activity and Reactive Oxygen Species
Thi‐Ngoc‐Suong HoABSTRACT
This study examines the impact of Ti: Si precursor ratios and synthesis pH on the structural properties and photocatalytic efficiency of TiO 2 –SiO 2 composites. The TiO 2 –SiO 2 were successfully synthesized via the sol‐gel method, utilizing titanium butoxide (Ti(OBu) 4 ) and tetraethyl orthosilicate (TEOS) as precursors. A controlled pH of 4 was applied during the hydrolysis of the TiO 2 precursor to enhance phase interaction between the components. The structural and physicochemical properties of the resulting composites were analyzed using X‐ray diffraction (XRD), Transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area analysis, and Diffuse reflectance spectroscopy (DRS). XRD confirmed anatase TiO 2 and amorphous SiO 2 , indicating good dispersion and interaction between components. Among the prepared composites, the TiO 2 –SiO 2 with a Ti: Si ratio of 95:5 exhibited the highest surface area (170.93 m 2 /g), much greater than pristine TiO 2 . The photocatalytic activity was evaluated by phenol degradation under simulated natural light irradiation (initial concentration: 10 mg/L, catalyst loading: 1 g/L, irradiation time: 4 h), achieving 91.5% degradation efficiency. Radical scavenging experiments revealed a pronounced inhibition effect, indicating that superoxide radicals (•O 2 − ) play a dominant role in photocatalytic degradation of phenol. These results suggest that the TiO 2 –SiO 2 composite is a promising material system for various environmental photocatalysis applications.