TiO_2掺杂CuMnCe/Al_2O_3催化剂对甲烷催化燃烧脱氧反应的影响

以掺杂了不同TiO_2含量的Al_2O_3作为载体,通过等体积浸渍法制备了一系列不同TiO_2含量的CuMnCe/TiO_2-Al_2O_3催化剂,用BET、H_2-TPR、XRD和XPS表征技术对催化剂物理化学性质进行表征,并考察了催化剂在含甲烷气脱氧反应中的催化性能。结果表明,在载体中添加TiO_2对催化剂活性组分的晶相结构和分散度没有明显影响;但有效改善了Al_2O_3载体抗烧结能力;增加了CuMnCe/Al_2O_3催化剂表面Ce~(3+)/(Ce~(3+)+Ce~(4+))的相对含量,从而提高了活性氧的移动性,且使催化剂表面可氧化还原物种含量和表面吸附氧Osur/(Osur+Olatt)的含量增多。有效改善了催化剂在含甲烷气催化燃烧脱氧上的催化活性。其中,CuMnCe/4%TiO_2-Al_2O_3表现出最优的催化活性,在387℃时可使含甲烷气中氧气的转化率达到100%。

Effect of TiO2 doping on methane catalytic combustion deoxidation of CuMnCe/Al2O3 catalyst

CuMnCe/TiO₂-Al₂O₃ catalysts with different TiO₂ contents were prepared by the co-impregnation method and characterized by BET, XRD, XPS and H₂-TPR techniques.The catalytic performance in methane deoxidation reaction were investigated using CGK-5A fixed bed reactor.Results showed that doping some TiO₂ in the Al₂O₃ support has no effect on the crystalline structure of the active ingredient.But it can effectively improve Al₂O₃ support sintering resistance and thermal stability, furthermore, it increases content of Ce³⁺/(Ce³⁺+Ce⁴⁺) in the CuMnCe/Al₂O₃ catalysts, which improves the mobility of oxygen.Besides, the content of adsorbed oxygen O_sur/(O_sur+O_latt) and reducible species in the catalyst surface are increased.Thus, effectively, doping some TiO₂ into the Al₂O₃ support improved the catalytic activity of deoxygenation catalyst for methane combustion.CuMnCe/4% TiO₂-Al₂O₃ exhibited optimum catalytic activity and oxygen conversion rate reached 100% at 387℃.