Manipulating the H<sub>2</sub>O<sub>2</sub> Reactivity on Pristine Anatase TiO<sub>2</sub> with Various Surface Features and Implications in Oxidation Reactions
Guohan Sun, Quan Wang, Yin‐Song Liao, Yifan Cui, Linyuan Tian, Jyh‐Pin Chou, Yufei Zhao, Yung‐Kang Peng
Abstract
Anatase TiO 2 is commonly used as a catalyst/support in reactions involving H 2 O 2, yet the understanding of interactions between common TiO 2 surfaces and H 2 O 2 remains limited. Herein, we synthesized well-defined TiO 2 crystallites with (101), (001), and fluorine-modified (001) [F-(001)] surfaces to examine how surface features, including the arrangement of five-coordinated Ti (Ti 5c ) sites and the presence of fluorine, influence H 2 O 2 activation. Our findings reveal that these surface features significantly affect the physiochemical properties of adsorbed H 2 O 2 . Specifically, fluorine on the F-(001) surface introduces an additional hydrogen bond to the Ti 5c -peroxo species, altering the electronic structure of H 2 O 2 compared to those with the (101) and (001) surfaces. Using cyclohexene as a probe substrate, we successfully distinguished the reactivities of the Ti 5c -peroxo species. The activity of those on the F-(001) surface was significantly higher than the activity of those on the (001) surface, while the (101) surface showed negligible oxidation activity. These insights can guide the design of TiO 2 -based catalysts for H 2 O 2 -related reactions.