Unravelling K promoter effects in Cu based catalysts for the reverse water gas shift reaction.

Syngas synthesis via reverse gas shift reaction is a promising approach to integrate CO2 in industrial processes. Insight into catalyst design is therefore required to develop highly active and selective catalysts that minimize side reactions, such as CO2 methanation. Potassium is an effective promoter for Cu-based catalysts, however, its promotional effect has not been fully elucidated, i.e. the nature of the Cu-K interaction and the reducing effect of K over Cu. The addition of K has led to greatly enhanced activity, selectivity and stability of the Cu catalysts during RWGS reaction, favouring syngas production. The unique capabilities of BM28/ID26 beamlines allow us to study the evolution of oxidation state and atomic coordination of K and Cu in-situ as a function of the gas feed composition (% of H2) and support material (SiO2 or C). We aim to obtain detailed information concerning the K-Cu interaction, correlating it to the observed performances during RWGS reaction.