Ni Doping Promotes C-H Bond Activation and Conversion of Key Intermediates for Total Oxidation of Methane over Co₃O₄ Catalysts

The efficient catalysis of light alkanes, such as extremely stable methane (CH4), continues to be a pressing challenge. We successfully introduced Ni ions into the Co3O4 spinel structural lattice, investigating the mechanism of Ni ions synergizing with Co to promote the low-temperature total oxidation of methane, focusing on asymmetric Ni-O-Co sites. The results demonstrated that the modulation of the local charge by nickel ions leads to an enhanced capability of catalysts to activate methane molecules while significantly reducing the energy barrier for the conversion of the key intermediate species OCHO to CO2, which was attributed to the electron transport channel constructed by Ni doping. In addition, the oxygen vacancy generation energy of the Ni-O-Co active composite sites was significantly reduced, leading to a remarkable increase in the adsorption activation capacity for gaseous oxygen and a significant enhancement of oxygen species mobility. This paper is of immense significance for understanding the mechanism of Ni doping to enhance the methane activity of cobalt-based catalysts.