Recent advances in the optimization of operating parameter for improving indoor VOC photocatalytic purification using TiO2-based photocatalysts.

TiO2-based photocatalytic technology has been widely used for indoor VOC purification. The operational parameters significantly influence the photocatalytic degradation of VOCs; therefore, comprehensively understanding their influence on the catalytic performance of photocatalytic systems is the key to securing the best photocatalytic reactor operation and improving the photocatalytic decomposition of indoor VOCs over TiO2-based photocatalysts. This review focuses on the key operational and intrinsic parameters (light source and intensity, TiO2 deactivation, nature of the VOCs and inlet VOC concentration, other gaseous compounds, relative humidity, temperature, airflow rate, oxygen content and reactors) that significantly influence photocatalytic degradation, and their influences on VOC PCO are systematically investigated. To the best of our knowledge, few reviews have focused on the optimization of operating parameters to improve the photocatalytic purification of indoor VOCs. The deactivation mechanisms and regeneration methods of photocatalysts are discussed, and possible strategies for reducing photocatalyst deactivation are also reviewed. The development and application of four typical photocatalytic reactors (honeycomb, annular, monolith and membranous reactors) are summarized. Finally, the challenges and future developments of operating parameter optimization for improving the photocatalytic purification of indoor VOCs are proposed. Hence, this review provides an in-depth summary of the primary operating parameters affecting the photocatalytic degradation of VOCs and discusses strategies for optimizing these parameters to enhance VOC removal.