Innovative defect engineering

Abstract

Volatile Organic Compounds (VOCs) pose significant environmental and health risks, requiring the advancement of effective control techniques. This study presents a novel and cost-effective synthesis method for incorporating Ti3+ sites and oxygen vacancies into TiO2 photocatalysts through sulfur doping, varying the thiourea content during synthesis. The synthesized modified TiO2/SiO2 materials were fully characterized using various techniques, including XRD, TEM, SEM, XPS, EPR, PL and BET. The analysis revealed the presence of crystalline defects. Notably, the EPR analysis indicated a correlation between the increase in bulk defects and the higher thiourea content. The photocatalytic efficiency of the synthesized materials was evaluated using n-hexane in a gas-solid reactor under UV–VIS radiation, showing a significant increase (34.2 % – 61.2 %) in degradation with the introduction of defects in the material. The operating conditions, such as humidity and the presence of oxygen, were varied, revealing a strong influence on the synthesized photocatalysts containing crystal defects. Notably, low humidity substantially increased photocatalytic activity, reaching 78.6 % degradation at 0 % of relative humidity. The stability of the material was examined over 180 min, with sustained high photocatalytic activity. Kinetic studies were carried out to explore varying input concentrations and transient regimes, providing valuable information on the performance of the continuous gas solid photocatalytic reactor (GSPR). This innovative synthesis approach is thus promising for efficient VOCs abatement with improved material performance and stability.