Low-Temperature Oxidation of Methane on Rutile TiO2(110): Identifying the Role of Surface Oxygen Species

Yuemiao Lai; Ruimin Wang; Yi Zeng; Fangliang Li; Xiao Chen; Tao Wang; Hongjun Fan; Qing Guo

doi:10.1021/jacsau.3c00771

Low-Temperature Oxidation of Methane on Rutile TiO₂(110): Identifying the Role of Surface Oxygen Species

JACS Au. 2024 Mar 26;4(4):1396-1404. doi: 10.1021/jacsau.3c00771. eCollection 2024 Apr 22.

Authors

Yuemiao Lai¹, Ruimin Wang^{2

3}, Yi Zeng¹, Fangliang Li¹, Xiao Chen^{1

4}, Tao Wang¹, Hongjun Fan², Qing Guo¹

Affiliations

¹ Shenzhen Key Laboratory of Energy Chemistry & Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, PR China.
² State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, PR China.
³ School of Pharmacy, North China University of Science and Technology, Tangshan, Hebei 063210, PR China.
⁴ Institute of Advanced Science Facilities, Shenzhen, Guangdong 518107, PR China.

Abstract

Understanding the microkinetic mechanism underlying photocatalytic oxidative methane (CH₄) conversion is of significant importance for the successful design of efficient catalysts. Herein, CH₄ photooxidation has been systematically investigated on oxidized rutile(R)-TiO₂(110) at 60 K. Under 355 nm irradiation, the C-H bond activation of CH₄ is accomplished by the hole-trapped dangling O_Ti^- center rather than the hole-trapped O_b^- center via the Eley-Rideal reaction pathway, producing movable CH₃^• radicals. Subsequently, movable CH₃^• radicals encounter an O/OH species to form CH₃O/CH₃OH species, which could further dissociate into CH₂O under irradiation. However, the majority of the CH₃^• radical intermediate is ejected into a vacuum, which may induce radical-mediated reactions under ambient conditions. The result not only advances our knowledge about inert C-H bond activation but also provides a deep insight into the mechanism of photocatalytic CH₄ conversion, which will be helpful for the successful design of efficient catalysts.