Selective Oxidative Coupling of Methane to Ethylene in a Solid Oxide Electrolyser Based on Porous Single-Crystalline...

Catalytic conversion of CH₄ to C₂ H₄ plays an important role in the light olefin industry. Here, we report the electrochemical conversion of CH₄ to C₂ H₄ /C₂ H₆ at the anode with the electrolysis of CO₂ to CO at the cathode in a solid oxide electrolyser. We constructed well-defined interfaces that function as three-phase boundaries by exsolving single-crystalline Ni nanoparticles in porous single-crystalline CeO₂ monoliths. We engineered the chemical states and flux of active oxygen species for the oxidation of CH₄ at the anode by controlling voltage and temperature. We show the unprecedented C₂ selectivity (C₂ H₄ and C₂ H₆ ) of ≥99.5 % at a CH₄ conversion of ≈7 %. The electrolyser exhibits excellent durability without performance degradation being observed in a continuous operation of 100 hours. Our work enables a novel path for the selective conversion of CH₄ /CO₂ into useful chemicals, and the technique of building well-defined interfaces may find potential applications in other fields.