Photocatalytic destruction of volatile aromatic compounds by platinized titanium dioxide in relation to the relative effect of the number of methyl groups on the benzene ring

The photocatalytic destruction (PCD) of volatile organic compounds (VOC) into environmentally benign compounds is one of the most ideal routes for the management of indoor air quality. It is nevertheless not easy to achieve the mineralization of aromatic VOC through PCD technology because of their recalcitrant structures (i.e., conjugated pi benzene ring). In this research, the PCD potential against three model aromatic hydrocarbons (i.e., benzene (B), toluene (T), and m-xylene (X): namely, BTX) has been explored using a titanium dioxide (TiO2) supported platinum (Pt) catalyst after the high-temperature hydrogen (H-2)-based reduction (R) pre-treatment (i.e., Pt/TiO2-R). The effects of the key process variables (e.g., relative humidity (RH), oxygen (O-2) content, flow rate, VOC concentration, and the co presence of VOC) on the PCD efficiency and related mechanisms were also assessed in detail. The PCD efficiency is seen to increase with the rise in the increasing number of methyl groups on the benzene ring (in the order of benzene (46.5%), toluene (68.2%), and m-xylene (95.9%)), as the adsorption and activation of the VOC molecule on the photocatalyst surface are promoted by the increased distribution of electrons on the benzene ring. The BTX were oxidated subsequently by the photogenerated reactive oxygen species (ROS), i.e., the hydroxyl radicals (center dot OH) and superoxide anion radicals (center dot O-2(-)). The overall results of this study are expected to help expand the applicability of photocatalysis towards air quality management by offering detailed insights into the factors and processes governing the photocatalytic decomposition of aromatic VOCs.

Automated summary

The photocatalytic destruction of volatile organic compounds is an ideal method for managing indoor air quality. This study explores the potential of photocatalysis for the degradation of model aromatic hydrocarbons and provides detailed insights into the factors and processes governing their decomposition. The results are expected to contribute to the applicability of photocatalysis in air quality management.