Superoxide radical enhanced photocatalytic performance of styrene alters its degradation mechanism and intermediate health risk on TiO 2 /graphene surface

• Published in: Environmental research Vol. 195; p. 110747
• Main Authors: Chen, Jiangyao, Zhang, Zilong, Zhu, Weikun, Zhang, Liyun, Zhao, Baocong, Ji, Yuemeng, Li, Guiying, An, Taicheng
• Format: Journal Article
• Language: English
• Published: Netherlands 01.04.2021
• Subjects: Catalysis; Graphite; Humans; Oxides; Styrene - toxicity; Superoxides; Titanium; Enhanced degradation performance; Increased health risk; Promoted superoxide radical; Altered dominant intermediate; Graphene coupled semiconductor
• ISSN: 1096-0953

Enhancement of reactive oxygen species (ROS) on semiconductor coupled by carbon material promotes photocatalytic performance toward aromatic hydrocarbons, while the contribution to their degradation mechanism and health risk is not well understood. Herein, photocatalytic degradation of styrene on TiO and TiO /reduced graphene oxide (TiO /rGO) surface is compared under dry air condition to investigate the role of ·O in styrene degradation. TiO /rGO shows 4.8 times higher degradation efficiency than that of TiO , resulting in 16% reduced production of intermediates with identical composition. The improved formation of ·O on TiO /rGO is confirmed responsible for these variations. Theoretical calculation further reveals the enhancement of ·O thermodynamically favoring conversion of styrene to acetophenone, turning the most dominant intermediate from benzoic acid on TiO to acetophenone on TiO /rGO. The accumulated formation of acetophenone on TiO /rGO poses increased acute threat to human beings. Our findings proclaim that ROS promoted photocatalytic performance of semiconductor after carbon material composition ultimately changes the priority order of degradation pathways to form by-product with higher threat toward human beings. And more attentions are advised focusing on the relevance with degradation efficiency, intermediate and toxicity of aromatic hydrocarbons on carbon material based photocatalyst.