Enhanced performance of Ru catalysts on high-entropy rare earth oxide supports for dry reforming of methane

Dry reforming of methane (DRM) is a promising route for the resource utilization of greenhouse gases; however, catalyst deactivation due to carbon deposition remains a major challenge. In this work, Ru-based catalysts supported on high-entropy rare-earth oxide (HEO, LaPrSmEuNdOx), medium-entropy oxide (MEO, LaPrSmOx), and single-component La₂O₃ were synthesized to investigate the role of configurational entropy of oxide support in catalytic performance and mechanism towards DRM reaction. Ru/HEO, featuring a fluorite structure and highly dispersed Ru sites, demonstrated superior activity, H₂/CO ratio, and 50-hour coke-resistant stability at 650 °C compared to Ru/MEO and Ru/La₂O₃. Catalytic studies, temperature-programmed characterizations and spectral evidence revealed that Ru/HEO selectively activates CH₄ via partial dissociation to CHx* and facilitates CO₂ activation by proper surface basicity and enhanced oxygen mobility and oxygen vacancy density. The in-situ DRIFT spectra identified the key reaction intermediates, confirming a cooperative conversion pathway of CH₄ and CO₂ on Ru/HEO for boosted activity and stability. This work provides insights into the entropy effect-driven structure design of active, anti-coking metal catalysts and mechanistic understanding of DRM reaction pathways.