Photocatalytic materials for indoor air purification systems: An updated mini-review

Although photocatalytic materials have been under extensive investigation for several decades, attempts to improve the current well-studied photocatalysts and develop novel photocatalysts for indoor air purification are still ongoing. The present work examines the progress made over the past three years in the application of photocatalysts for degrading gas-phase air pollutants. Three main issues are considered: (1) the basic principles of using photocatalytic degradation for air purification are briefly elucidated, including mass transfer, photocatalytic reaction mechanisms, degradation pathways, and strategies to enhance the photocatalytic efficiency; (2) novel photocatalytic systems with improved photocatalytic performance for the removal of air pollutants are discussed, focusing on state-of-the-art photocatalysts; and (3) future trends in the development of photocatalytic materials for commercialization are considered.