Open AccessIn situ X‐ray absorption spectroscopic studies of TiO 2 photocatalytic active sites for degradation of trace CHCl 3 in drinking water
Author(s) -
Hsiung T.-L.,
Wei L.-W.,
Huang H.-L.,
Wang H. Paul
Publication year - 2021
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577521008973
Subject(s) - photocatalysis , xanes , degradation (telecommunications) , photodegradation , absorption (acoustics) , materials science , amorphous solid , environmental chemistry , photochemistry , spectroscopy , catalysis , chemistry , organic chemistry , physics , telecommunications , quantum mechanics , computer science , composite material
Toxic disinfection byproducts such as trihalomethanes ( e.g. CHCl 3 ) are often found after chlorination of drinking water. It has been found that photocatalytic degradation of trace CHCl 3 in drinking water generally lacks an expected relationship with the crystalline phase, band‐gap energy or the particle sizes of the TiO 2 ‐based photocatalysts used such as nano TiO 2 on SBA‐15 (Santa Barbara amorphous‐15), TiO 2 clusters (TiO 2 –SiO 2 ) and atomic dispersed Ti [Ti‐MCM‐41 (Mobil Composition of Matter)]. To engineer capable TiO 2 photocatalysts, a better understanding of their photoactive sites is of great importance and interest. Using in situ X‐ray absorption near‐edge structure (XANES) spectroscopy, the A 1 (4969 eV), A 2 (4971 eV) and A 3 (4972 eV) sites in TiO 2 can be distinguished as four‐, five‐ and six‐ coordinated Ti species, respectively. Notably, the A 2 Ti sites that are the main photocatalytic species of TiO 2 are shown to be accountable for about 95% of the photocatalytic degradation of trace CHCl 3 in drinking water (7.2 p.p.m. CHCl 3 gTiO 2 −1 h −1 ). This work reveals that the A 2 Ti species of a TiO 2 ‐based photocatalyst are mainly responsible for the photocatalytic reactivity, especially in photocatalytic degradation of CHCl 3 in drinking water.