Strategic defect engineering in TiO2 catalysts through electron beam irradiation: Unraveling enhanced photocatalytic pathways for multicomponent VOCs degradation

Abstract

Defect engineering improves catalytic activity, electron transport efficiency, and stability by introducing defects such as oxygen vacancies, offering significant potential for applications in environmental remediation and energy conversion. Electron beam (EB) irradiation has emerged as a key technique in defect engineering, renowned for its mild reaction conditions and precise defect construction capabilities. This study synthesized defect-rich commercial TiO₂ catalysts (P25) using high-energy EB irradiation to investigate the photodegradation efficiency of multicomponent VOCs. The EB irradiation technique promoted the formation of oxygen vacancies, which played a key role in the adsorption and activation of pollutant molecules. DFT calculations further confirmed the superior photocatalytic activity of the irradiated P25 catalyst. The photodegradation experiments showed that the 300P25 degraded pure ethyl acetate up to 99.05 % (40 min) and acetone up to 97.14 % (60 min), but toluene only up to 7.34 % (60 min). Interestingly, in acetone and toluene mixture, 300P25 achieved toluene removal as high as 68 % (60 min) with a rate constant (k) of 0.0181 min⁻¹, a 12.1-fold than pure toluene (0.0015 min⁻¹). In-situ infrared spectroscopy analysis revealed that during the simultaneous degradation of toluene and acetone, acetone significantly promoted the deep oxidation of toluene, leading to the rapid oxidation of intermediate products (benzyl alcohol and benzaldehyde) to benzoic acid and smaller molecules. This work provides important guidance for developing efficient and stable photocatalysts for degrading multicomponent VOCs.