Oxyphilic Ru-O-Mn²⁺ Interfaces on Ru/MnO Catalysts: Unprecedented Activity for Low-Temperature CO₂ Methanation

Catalytic CO₂ methanation using renewable H₂ presents a promising strategy for carbon neutrality and renewable energy storage, yet achieving high efficiency at low temperatures remains a formidable challenge. Herein, we report a Ru/MnO catalyst featuring in situ constructed highly oxyphilic Ru-O-Mn²⁺ interfaces that demonstrate remarkable CO₂ methanation performance. At 180°C and a space velocity of 36,000 mL g^-1 h^-1, the catalyst achieves 94.9% CO₂ conversion with a CH₄ production rate of 84.7 µmol g_cat ^-1 s^-1, surpassing state-of-the-art catalysts, while maintaining robust stability. Combined experimental and theoretical investigations identify the Ru-O-Mn²⁺ interface as the pivotal active center, revealing a direct positive correlation between the amount of interfacial oxyphilic species, the quantity of weakly adsorbed CO₂, and the turnover frequency. This oxyphilic interfacial site establishes an extensive network for weak CO₂ adsorption, thereby promoting CO₂ activation at low temperatures. The successful extension of this strategy to Ni-based systems underscores the universality of MnO-mediated interfacial engineering. These findings establish a new design paradigm for low-temperature catalysis and deepen the fundamental understanding of interfacial oxyphilicity in heterogeneous catalysis.