Two-dimensional g-C3N4 Compositing with Ag-TiO2 as Deactivation Resistant Photocatalyst for Degradation of Gaseous Acetaldehyde

The photocatalysts deactivation is one of the major issues, which lowers the usefulness of photocatalytic oxidation technology for the removal of low content volatile organic compounds (VOCs). Here, we carried out a series of experiments to demonstrate that the photocatalysts stability could be significantly improved via coupling the oxide base semiconductors, i.e., TiO 2 with 2D materials such as graphitic carbon nitride (g-C 3 N 4 ). Initially, when Ag modified TiO 2 (AT) was used for the gaseous acetaldehyde degradation, a robust deactivation was observed within 60 min. The AT catalyst completely lost its activity when the reaction time was extended to 400 min. On the contrary, the g-C 3 N 4 modified AT (CAT) showed superior photocatalytic performance and improved stability (600 min). The in-situ FT-IR, PL, and photocurrent studies suggested that the accumulation of reaction intermediates in the case of AT fundamentally caused the deactivation. However, the g-C 3 N 4 provided excessive adsorption sites for the reaction by-products which improved the stability. Additionally, the PL and ESR studies suggested that the existence of g-C 3 N 4 improved the charge separation and production of reactive oxygen species, which facilitated the photodegradation of acetaldehyde and ultimate reaction products. This study realizes the usefulness of 2D materials for developing stable and visible light active photocatalysts for applications in sustainable VOC abatement technology.