Combination of rGO/S, N/TiO₂ for the enhancement of visible light-driven toluene photocatalytic degradation

Toluene is one type of common volatile organic compounds that is harmful to human health. Therefore, the degradation of toluene is critical to improving air quality value. Performance improvement of TiO₂, a typically applied photocatalyst, has advantages in light absorption and electron transfer process. In this study, the TiO₂ catalyst was improved by the doping of reduced graphene oxide (rGO), sulfur, and nitrogen (S, N) elements. The highest toluene photocatalytic degradation was performed under the composition of 1wt%rGO/S_0.05N_0.1TiO₂. Improvement in photocatalytic activity was achieved by higher specific surface area, formation of oxygen-containing functional group, and chemical defect structure. However, a higher amount of rGO addition creates the shielding effect and inhibits the light penetration. Moreover, the relative humidity and applied temperature influence the photocatalytic activity through the competitive adsorption or increase the collisions frequency, respectively. During the photocatalytic degradation using 0.1wt%rGO/S_0.05N_0.1TiO₂, toluene will be converted into benzyl alcohol, benzaldehyde, benzoic acid, water, and carbon dioxide.