Cooperative catalysis between Ce³⁺ sites and Ag nanoparticles enabling nonoxidative coupling of methane to ethane

Photocatalytic nonoxidative coupling of methane (CH₄, NOCM) to ethane (C₂H₆) is a promising route for CH₄ valorization, yet its efficient implementation requires the seamless coordination of CH₄ adsorption, C-H bond activation, and C-C coupling. This intrinsic complexity makes it fundamentally challenging for a single type of active site to drive the entire NOCM process efficiently. Herein, we induce the formation of Ce³⁺ sites on the surface of CeO₂ by loading Ag nanoparticles (NPs) for NOCM, and achieve highly efficient and selective conversion of CH₄ to C₂H₆. Mechanistic studies indicate that the Ce³⁺ sites enhance CH₄ adsorption and facilitate C-H bond activation to generate methyl radicals (˙CH₃). Subsequently, Ag NPs promote the coupling of ˙CH₃, ultimately producing C₂H₆. This study presents a synergistic catalysis strategy for designing efficient photocatalysts to achieve the selective coupling of CH₄ into higher-value chemicals.