Entropy-Driven Dynamic Oxygen Cycling on High-Entropy Oxides Enables Coke-Resistant Dry Reforming of Methane

Catalyst deactivation caused by carbon deposition and metal sintering remains a major challenge for dry reforming of methane (DRM). Herein, we designed and synthesized a Ce-based high-entropy oxide catalyst (NiCoMgAlZrCe-HEO). Configurational entropy stabilizes a multication-disordered lattice with pronounced local distortion, which modulates the oxygen coordination environment and enhances the lattice-oxygen reactivity. The NiCo alloy nanoparticles formed through in situ reductive exsolution are anchored to the HEO matrix, thereby enhancing the resistance to sintering. The reduced NiCoMgAlZrCe-HEO exhibits CH4 and CO2 conversions of 80.2% and 87.3%, respectively, at 700 °C and maintains stable catalytic performance over 500 h. Combined experimental characterization and density functional theory calculations reveal a dynamic oxygen-cycling mechanism enabled by the high-entropy structure. Mobile lattice oxygen favors the selective activation of CH4 by promoting the formation of *CH3O intermediates, thereby suppressing the carbon-forming pathways. Meanwhile, abundant oxygen vacancies facilitate CO2 activation, accelerating the replenishment of the reactive lattice oxygen. This work offers a feasible strategy for designing DRM catalysts that are resistant to coking and sintering based on configurational entropy regulation.