Operando X-ray Absorption Spectroscopy Study of Copper-Based Catalysts for Low-Temperature RWGS Reaction

The Reverse Water-Gas Shift (RWGS) reaction is considered a key technology for CO2 valorization. However, active and selective catalysts at low temperatures (<300 °C) are scarce due to the thermodynamic nature of the reaction and lack of clear trends in catalyst design. We have developed Cu-based catalysts supported on mesoporous CeO2-Al2O3 and promoted with K, reaching high activity and complete selectivity for the RWGS reaction in the low temperature range. Initial characterization has demonstrated the formation of highly dispersed Cu-K active sites and the stabilization of the Cu+/Cu0 and K+ oxidation states in reducing conditions, which we believe to be responsible for the observed high catalytic activity and selectivity.

The aim of this proposal is to use operando X-ray Absorption Spectroscopy (XAS) to study the oxidation states, coordination environment, and dynamic structural evolution of Cu and K species under reaction conditions. This will provide mechanistic insights into the role of the Cu+/Cu0 pair and the influence of potassium promotion and the effect of the support on catalytic performance, helping elucidate trends in catalyst design and valuable insights for the development of future catalysts for the RWGS reaction.