Constructing CuO-CeO2 heterointerfaces for enhanced Low-Temperature CO oxidation and SO2 resistance

CuO-CeO₂ composite catalyst for low temperature CO oxidation was fabricated via an impregnation method. The prepared composite CuO-CeO₂ achieved 50 % and 100 % conversion at approximately ∼ 70℃ and ∼ 110℃ (denoted as T₅₀ and T₁₀₀), respectively. The enhanced catalytic activities were attributed to the formation of abundant CuO/CeO₂ heterostructures, which increased the concentration of oxygen vacancies in their lattices. In addition, the pore structure of the CuO-CeO₂ composite has also been optimized during the impregnation synthesis process. Compared with bare CeO₂, which only possesses micropores, CuO-CeO₂ forms more mesopores on its surface, which assists in reducing the deposition rate of sulfate species on the surface. The SO₂ tolerance of the catalyst and hence its stability towards practical industrial flue gas treatment is significantly promoted. Furthermore, Density Functional Theory (DFT) was also performed to explore the mechanism of CO oxidation on the CuO-CeO₂. It was found that the oxygen vacancy can be easily formed on the CuO/CeO₂ heterointerfaces; the adsorption energy (ΔG) of CO was therefore decreased to 0.15 eV, much lower than that of bare CeO₂ (0.53 eV). Besides, the center of f electrons of Ce in CeO₂ rises from −0.55 eV to – 1.71 eV by introducing CuO, suggesting that the f electrons in Ce become more active, which is beneficial for CO to adsorb.