Unexpected C-C Bond Cleavage Mechanism in Ethylene Combustion at Low Temperature: Origin and Implications

Achieving low-temperature C = C bond activation has been of interest in heterogeneous catalysis, and understanding the subject (i.e., establishing the mechanism and identifying the origin) is desirable. Herein, taking the CH₂CH₂ combustion on spinel Co₃O₄(110) as an example, we report a systematic investigation on the C-C bond breaking processes using first-principles calculations. An unexpected pathway for C-C cracking, called the valency-saturation-driven mechanism, is determined, and the high activity of Co₃O₄ in catalyzing CH₂CH₂ combustion at low temperature is rationalized. More importantly, some basic C-C bond activation rules on metal oxides with isolated single-atom sites, which differ from the traditional metal catalysis with multiatom active sites, are revealed. The understandings derived from this work may underpin the structure-activity relationship in oxide catalysis.