文献类型：期刊文献

英文题名：Revisiting Heterolytic Cleavage Mechanism of Methane C-H Bond Activation over Metal Oxide Surfaces

作者：Cheng, Lu[1,2];Lu, Jiaye[1,2];Xiang, Qian[1,2];Cao, Xiao-Ming[1,2,3]

机构：[1]East China Univ Sci & Technol, Ctr Computat Chem, State Key Lab Green Chem Engn & Ind Catalysis, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Res Inst Ind Catalysis, Shanghai 200237, Peoples R China;[3]Shanghai Jiao Tong Univ, Sch Chem & Chem Engn, Shanghai 200240, Peoples R China

年份：2025

卷号：16

期号：10

起止页码：2460

外文期刊名：JOURNAL OF PHYSICAL CHEMISTRY LETTERS

收录：;EI(收录号：20251018017946);WOS:【SCI-EXPANDED(收录号:WOS:001435156700001)】；

基金：This work was supported by the National Key R&D Project of China (2023YFA1507601) and the National Natural Science Foundation of China (22022302, 92045303, and 91845111). We acknowledge The Light of Huhhot at IMHPC (Inner Mongolia High Performance Computing Public Service Platform) for the support of high-performance calculation resources.

语种：英文

外文关键词：Alkali metals - Alkaline earth metals - Bioremediation - Coulomb blockade - Dynamic response - Free radical reactions - Integrated circuit design - Negative ions - Photodissociation - Photoionization - Photolysis - Positive ions - Structural dynamics - Transition metal oxides

摘要：The understanding of C-H bond activation could facilitate the design of improved catalysts for the conversion of methane to valuable products. However, its mechanism remains controversial, particularly with regard to metal oxides. This study aims to shed light on this issue by systematically investigating methane C-H bond activation across various pristine metal oxide surfaces and revisiting the prevailing heterolytic cleavage mechanism. It is found that the so-called "heterolytic cleavage mechanism" for methane activation could be classified into two distinct mechanisms on bare metal oxide surfaces: the real heterolytic cleavage mechanism over flat nonreducible alkali and alkaline-earth metal oxide surfaces (N-MOSs) and a ligand-to-metal charge transfer (LMCT)-enabled hydrogen atom transfer (HAT) mechanism over reducible metal oxide surfaces (R-MOSs). The dominant mechanism is determined by the Coulomb interaction between methane and the surface at the transition state and the energy of LMCT (E LMCT). Strong Coulomb interactions favor the heterolytic cleavage mechanism on bare N-MOSs, while the opposite favors the LMCT-enabled HAT mechanism on R-MOSs. Nevertheless, the heterolytic cleavage mechanism might have difficulty occurring under the reaction conditions of methane oxidation since the strong chemisorption of dioxygen over alkali and alkaline metal oxide surfaces would render the methane far from the surface, significantly weakening the Coulomb interaction. Doping can manipulate the electronic structure of lattice oxygen, potentially reducing E LMCT and even bypassing LMCT to directly generate reactive oxygen radicals, thus accelerating C-H activation. Additionally, these distinct mechanisms can influence subsequent steps, such as C-O coupling. C-H bond activation through the LMCT-enabled mechanism would be a prerequisite to trigger C-O coupling. This study provides valuable insights into the design of targeted catalysts with desired activity and selectivity for efficient and controlled methane conversion.