Abstract: The water-gas shift reaction was used to evaluate a series of La₂O₃ modified CuO/CeO₂ catalysts that were prepared by a parallel co-precipitation method. The catalytic activity and thermal stability improved significantly upon the introduction of La₂O₃, and CuO/CeO₂-La₂O₃ (2 wt%) gave the highest activity and had the best thermal stability. The microstructure of the as-prepared CuO/CeO₂-La₂O₃ catalysts and/or the CeO₂-La₂O₃ supports was characterized by X-ray diffraction, N₂ physisorption, Raman spectroscopy, and temperature-programmed reduction. The results indicate that larger specific surface areas and smaller crystal sizes of CuO and CeO₂ result in improved catalytic performance for the as-prepared catalysts. Moreover, the incorporation of La³⁺ into the ceria lattice promotes the generation of oxygen vacancies leading to a higher number of moderate copper oxides that interact with surface oxygen vacancies on the surface of the ceria. This enhances the activity and thermal stability of the CuO/CeO₂ catalyst.

Key words: copper oxide, ceria, lanthanum oxide, water-gas shift reaction, oxygen vacancy, Raman spectroscopy