Mn-Ce复合金属氧化物催化氧化甲苯性能

通过等体积浸渍法制备了一系列Mn-Ce/γ-Al₂O₃催化剂, 并考察不同CeO₂负载量对MnO₂/γ-Al₂O₃催化剂催化氧化甲苯性能的影响。利用XRD、N₂吸脱附曲线、TEM、H₂-TPR、XPS和O₂-TPD等方法表征催化剂比表面积、表面形貌及氧化还原性能。结果表明，CeO₂的负载一定程度上降低了MnO₂/γ-Al₂O₃催化剂的比表面积, 且催化剂仍保持介孔结构。CeO₂的存在增加了催化剂表面的化学吸附氧含量，其良好的储放氧能力促进了Mn³⁺向Mn⁴⁺的转化；Mn和Ce之间存在较强的协同作用, 与MnO_x相邻的CeO₂更容易打开Ce—O键释放活性氧, 加速氧化还原进程，Mn_0.6Ce_0.4/γ-Al₂O₃催化剂T₁₀和T₉₀与MnO₂/γ-Al₂O₃催化剂相比分别降低20和40 ℃。本研究可为VOCs催化氧化技术中低成本金属催化剂的开发提供参考。

Catalytic oxidation of toluene over Mn-Ce composite metal oxide catalyst

A series of Mn-Ce/γ-Al2O3 catalysts were prepared by the method of equal volume impregnation, and the effect of different CeO2 loading on the catalytic oxidation performance of MnO2/γ-Al2O3 catalysts was investigated. The specific surface area, surface morphology and oxidation-reduction performance of the catalysts were characterized by XRD, N2 adsorption-desorption curve, TEM, H2-TPR, XPS and O2-TPD. The results showed that CeO2 loading reduced the specific surface area of MnO2/γ-Al2O3 catalysts to some extent, and the catalysts still maintained mesoporous structure. The presence of CeO2 increased the chemical adsorption oxygen content on the surface of the catalyst, and its good oxygen storage capacity promoted the transformation of Mn3+ to Mn4+. There was a strong synergistic effect between Mn and Ce, and the CeO2 adjacent to MnOx was more likely to break the Ce-O bond to release active oxygen and accelerate the oxidation-reduction process. Compared with MnO2/γ-Al2O3 catalyst, T10 and T90 of Mn0.6Ce0.4/γ-Al2O3 catalyst reduced 20 and 40 ℃, respectively.