Effect of different supports on activity of Mn–Ce binary oxides catalysts for toluene combustion

The effects of support materials on catalytic performance were investigated in catalytic removal of toluene. And the Mn–Ce binary oxides as active components were supported on ZrO₂, SiO₂, γ-Al₂O₃ and TiO₂ support materials. Many techniques, including X-ray diffraction (XRD), Brunauer–Emmett–Teller method (BET), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) and NH₃-temperature-programmed desorption (NH₃-TPD), were used to characterize physicochemical properties. Among the different catalysts, the MnCe/ZrO₂ catalyst with the lowest specific surface area (39.7 m²/g) shows the best catalytic activity. In terms of toluene conversion, the activity order is as follows: MnCe/ZrO₂ > MnCe/TiO₂ ≈ MnCe/SiO₂ > MnCe/Al₂O₃. The better performance of MnCe/ZrO₂ should be attributed to the low-temperature reducibility, and abundant surface species (Mn⁴⁺ and lattice oxygen). And XPS and TPR results reveal that more surface abundant Mn and Ce elements generate good interaction in MnCe/ZrO₂. The weak interaction between metal oxide and support also boosts the dispersion and complete reduction of MnCe oxides at low temperature. In addition, the in-situ DRIFTS results clarify that the carbonate species are main intermediates in MnCe/ZrO₂ sample during surface reaction process.