Mechanochemical synthesis of highly dispersed Cu on CeO2 for the reverse water-gas shift reaction

Copper-based catalysts are highly promising for carbon dioxide (CO2) reduction to carbon monoxide (CO) via the reverse water-gas shift (RWGS) reaction, owing to their efficiency, copper abundance, sustainability and cost-effectiveness. However, enhancing CO2 conversion and CO selectivity requires achieving high copper dispersion through a scalable and economical synthesis method. In this study, Cu was combined with CeO2 rods via a mechanochemical ball-milling approach to optimize performance in the RWGS reaction. Comprehensive characterization and kinetic analysis revealed how metal content influences catalyst architecture and activity. Additionally, in situ diffuse reflectance infrared Fourier transform spectroscopy was used to investigate the nature of copper species at different dispersion levels and elucidate the reaction pathway. Notably, the Cu/CeO2 catalyst with a high Cu loading (~5 wt%) and well-dispersed active sites achieved an activity (RCu(CO2)) of 4.8◊10−5 molCO2 mCu−2 s−1 with over 99% CO selectivity at 450 °C. These findings provide a robust strategy for developing high-performance Cu-based catalysts for the RWGS reaction.