Volatile organic compounds (VOCs) removal by photocatalysts: A review.

Amplified anthropogenic release of volatile organic compounds (VOCs) gets worse air quality and human health. Photocatalytic degradation of VOCs is the practical strategy due to its low cost, simplicity, high efficiency, and environmental sustainability. Different types of photocatalyst activated by UV and visible lights are applied for VOC degradation. This review tries to investigate the state-of-art of recently published papers on this subject with a focus on the high-efficiency photocatalyst. The novel photocatalysts are introduced and enhancing photocatalytic activity strategies such as the hybrid of two/three photocatalyst, impurity doping, and heterojunctions with narrow bandgap semiconductors have been explained. The procedures of visible light activation of the photocatalysts are discussed with attention to current problems and future challenges. In addition, effective operational parameters in the photocatalytic degradation of VOCs have been reviewed with their advantages and drawbacks. A series of strategies are developed for the efficient utilization of visible light photocatalysts and improving new materials or design structures to degrade produced toxic intermediates/by-products during photocatalytic degradation of VOCs. This review shows that there are significant challenges in the applications of photocatalysts in the selective removal of VOCs. Several approaches should be combined to produce synergistic effects, which may lead to much higher photocatalytic performance than individual strategies. Another challenge is to develop efficient photocatalysts to meet real problems on an industrial scale.