Enhancing Value-Added CO Production from CO ₂ Hydrogenation by Tailoring the Ru-CeO ₂ Interface on MgO

Catalytic CO₂ hydrogenation presents a promising route for converting CO₂ into valuable products, contributing to the mitigation of net CO₂ emissions. Supported Ru catalysts have recently gained considerable attention due to their tunability for 100% CO selectivity via the reverse water-gas shift pathway, effectively suppressing the competing methanation route. However, despite achieving full CO selectivity, the overall CO yield remains limited by low CO₂ conversion, necessitating further improvement. In this work, CeO₂ was introduced to modify a Ru/MgO single-atom catalyst for CO₂ hydrogenation. The resulting Ru-CeO₂/MgO catalyst, featuring abundant Ru-CeO₂ interfacial sites, exhibited a favorable balance of CO₂ conversion and CO selectivity, delivering the highest CO yield (32.5% at 500 °C), which is 9.0 and 1.8 times higher than that on Ru/MgO (3.6%) and Ru/CeO₂ (18.4%), respectively. Although the CO selectivity was slightly compromised due to enhanced CO binding at Ru-CeO₂ interfacial sites, H₂ was more efficiently activated at these interfaces and readily reacted with CO₂ adsorbed on CeO₂-MgO surfaces, thereby boosting the CO₂ hydrogenation activity and CO yield. This study underscores the critical role of Ru-metal oxide interface engineering in improving CO yield and advancing the rational design of highly efficient Ru catalysts for CO production from CO₂ hydrogenation.