The Role of Support Morphology and Impregnation Medium on the Water Gas Shift Activity of Ceria-Supported Copper Catalysts

The effect of support morphology and impregnation medium on the activity of Cu/CeO2 catalysts in the water gas shift reaction was investigated. Steady-state reaction experiments showed that the catalysts supported over CeO2 nanoparticles achieved significantly higher CO conversions than catalysts supported over nanorods, which achieved only marginally higher conversions than the bare support. The catalysts were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, N2O chemisorption, and H2-temperature-programmed reduction. Characterization of the catalysts showed that copper dispersion and catalytic activity were strongly correlated. Copper was observed to be better dispersed over CeO2 nanoparticles, whereas larger, crystalline CuO domains with properties closer to that of bulk CuO were identified over CeO2 nanorods. The finely dispersed copper species constitute the active sites for the WGS reaction over Cu/CeO2 catalysts.