Ru/Al₂O₃ is a highly stable, but less active catalyst for methanation reactions. Herein we report an effective approach to significantly improve its performance in the methanation of CO₂/H₂ mixtures. Highly active and stable Ru/γ‐Al₂O₃ catalysts were prepared by high‐temperature treatment in the reductive reaction gas. Operando/in situ spectroscopy and STEM imaging reveals that the strongly improved activity, by factors of 5 and 14 for CO and CO₂ methanation, is accompanied by a flattening of the Ru nanoparticles and the formation of highly basic hydroxylated alumina sites. We propose a modification of the metal–support interactions (MSIs) as the origin of the increased activity, caused by modification of the Al₂O₃ surface in the reductive atmosphere and an increased thermal mobility of the Ru nanoparticles, allowing their transfer to modified surface sites.

Oxygen vacancy structures on CeO ₂ nanocrystals vary with their morphologies and locally control the reactivity of isolated bridging hydroxyl groups.