Inverse CeO 2 /Cu Catalysts with Engineered Cu + ‐O V ‐Ce 3+ Interfacial Sites for Reverse Water Gas Shift Reaction

ABSTRACT The reverse water‐gas shift (RWGS) reaction can serve as a pivotal hub for converting CO 2 into value‐added chemicals. However, conventional Cu/CeO 2 catalysts are constrained by a limited metal‐oxide interfacial perimeter, suffering from both inadequate low‐temperature activity and poor stability. Herein, a series of CeO 2 /Cu‐x catalysts (where x is the Ce/Cu molar ratio) were synthesized via an oxalic acid‐assisted sol‐gel coprecipitation method, and tested for RWGS at 400°C and atmospheric pressure. The optimal inverse CeO 2 /Cu‐0.1 achieves an intrinsic reaction rate of 197.0 µmol·g cat −1 ·s −1 , which is 3.7 times higher than that of the conventional CeO 2 /Cu‐10 (53.1 µmol·g cat −1 ·s −1 ) and is much more stable. Structural analyses revealed that the CeO 2 /Cu‐0.1 is characterized by an inverse architecture of tiny CeO 2 crystallites (4.6 nm) on larger Cu particles (12.7 nm), which is distinct from conventional architecture of Cu clusters (3.3 nm) on larger CeO 2 particles (7.1 nm) for CeO 2 /Cu‐10. The inverse architecture significantly improves the density of Cu + ‐O V ‐Ce 3+ sites at the interfacial perimeter of CeO 2 /Cu, which facilitates the synergistic activation of H 2 and CO 2 as well as subsequent reaction, leading to lower reaction orders and a much higher intrinsic rate. This work demonstrates the inverse oxide/metal architecture with engineered oxide‐metal interfacial sites for enhancing RWGS.