Effect of B-Site Element on the Structure and Catalytic Performance for Toluene of the 3DOM CeBO₃ Catalyst

A series of 3DOM cerium-based perovskite catalysts with different B-site elements were prepared by the colloidal crystal template method and excess impregnation method with Cr, Ni, and Mn as the B-site elements. The physical and chemical properties of the catalysts were investigated by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H₂-TPR), and oxygen temperature-programmed desorption (O₂-TPD) characterization techniques. The results showed that the catalyst with Mn as the B-site element had a high-quality macropore structure (pore size 200-250 nm), large specific surface area (45.26 m²/g), and abundant surface adsorbed oxygen content (O_ads/O_latt = 0.46). The addition of manganese enhanced the low-temperature reducibility, and the main reduction peak was below 400 °C. The O₂-TPD results showed that 3DOM CeMnO₃ expressed the highest adsorption oxygen content. The 3DOM CeMnO₃ possessed the best catalytic performance with T_50% = 102 °C and T_90% = 203 °C during the catalytic oxidation of toluene. Intermediate product study hinted that toluene was first converted into benzoic acid and benzaldehyde and then further degraded into small molecules. The catalyst with the best activity also exhibited good stability, and toluene degradation rate remained above 85% at 200°C for more than 20 h of continuous experiments.