Facet-dependent intermediate formation and reaction mechanism of photocatalytic removing hydrophobic anthracene under simulated solar irradiation
By Qi, Weixiao; An, Xiaoqiang; Zhang, Fan; Liu, Huijuan; Qu, Jiuhui
Published in Applied Catalysis B: Environmental
2017
Abstract
Abstract The intrinsic impact of inherent structures of facet photocatalysts on the reaction pathways and mechanism is largely unknown, although it is of scientific and technological importance for the research of water remediation. In this paper, hydrophobic anthracene (Ant) and TiO2 with dominant 001, 010 and 101 facets were selected as typical examples, to demonstrate the significant influence of exposed facets on the radical formation and intermediate production. The results showed that 101 faceted TiO2 showed superior catalytic activity than 001 and 010 faceted TiO2 during the degradation of Ant under simulated solar irradiation, while 001 faceted TiO2 resulted in the largest production of anthraquione (AQ) intermediates. A fundamental study indicated that holes and oxygen played the important roles in the first step of catalytic oxidation of Ant on 001 and 010 faceted TiO2, while {OH} radical was the main species to degrade AQ. The electron spin resonance spectroscopy measurements showed that their different abilities for the in-situ formation of {OH} radicals led to the differences in the intermediate products and reaction pathways. This work provides new insights into the development of high-efficiency photocatalysts for pollutant elimination through crystal-facet tailoring.