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采用溶胶-凝胶法制备了系列Ce1-xMnxO2催化剂,运用BET,XRD,Raman,XPS和H2-TPR等方法对催化剂进行了表征。并考察了催化剂对CH2C l2催化氧化的性能。XRD结果表明,催化剂中Ce的加入可以有效抑制催化剂晶粒变大,且有部分Mn离子进入CeO2骨架中形成了固溶体;而XPS结果表明,催化剂中Mn物种以+3和+4价存在。H2-TPR结果表明,催化剂中Ce的加入降低了MnOx中晶格氧的还原温度。反应活性结果表明,Ce1-xMnxO2系列催化剂较纯CeO2,MnOx催化活性好,其本征活性顺序为Ce0.8Mn0.2O2>Ce0.6Mn0.4O2>Ce0.5Mn0.5O2>Ce0.4Mn0.6O2>Ce0.2Mn0.8O2>CeO2>MnOx。这可能是由于Ce的添加提高了催化剂中MnOx晶格氧的活泼程度,进而影响反应性能。
A series of Ce1-xMnxO2 catalysts were prepared by sol-gel method. The catalysts were characterized by BET, XRD, Raman, XPS and H2-TPR methods. The catalytic performance of the catalyst for CH2C12 catalytic oxidation was also investigated. The results of XRD show that the addition of Ce can effectively inhibit the growth of the catalyst grains, and some of the Mn ions enter the CeO2 framework to form a solid solution. The XPS results show that the Mn species exist in the catalysts at +3 and +4 valences. H2-TPR results show that the addition of Ce in the catalyst reduces the reduction temperature of lattice oxygen in MnOx. The results show that the catalytic activity of Ce1-xMnxO2 catalyst is better than that of pure CeO2 and MnOx, and its intrinsic activity order is Ce0.8Mn0.2O2> Ce0.6Mn0.4O2> Ce0.5Mn0.5O2> Ce0.4Mn0.6O2> Ce0 .2Mn0.8O2> CeO2> MnOx. This may be due to the addition of Ce increases the activity of MnOx lattice oxygen in the catalyst, thereby affecting the reaction performance.