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采用氨水共沉淀法制备了一系列铈基复合氧化物(Ce0.9M0.1O2,M=Cu、Cr、Zr、Ti、La),借助XRD、Raman、N2吸附-脱附、ESEM和H2-TPR等手段对复合氧化物的结构进行了表征,并考察了其在HCl催化氧化制Cl2过程中的性能.结果显示:Cu、Cr和Zr掺杂能显著减小复合氧化物晶粒尺寸,提高复合氧化物的比表面积和孔容,并提供更多的低温可还原氧物种.而La和Ti的掺杂可以获得较大的表面氧空位浓度以及增加高温可还原氧物种数目.复合氧化物结构和表面性质的变化显著影响了其HCl催化氧化活性,在430℃下铈基复合氧化物催化剂活性顺序为:Ce0.9Cu0.1O2>Ce0.9Cr0.1O2>Ce0.9Zr0.1O2>Ce0.9Ti0.1O2>Ce O2>Ce0.9La0.1O2,低温可还原氧物种数目直接与催化剂活性有关.反应动力学测试显示催化剂低温可还原氧物种有利于HCl在催化剂表面的吸附和活化,而催化剂表面的氧空位可以促进氧分子的吸附和活化.
A series of cerium-based composite oxides (Ce0.9M0.1O2, M = Cu, Cr, Zr, Ti and La) were prepared by aqueous coprecipitation method. XRD, Raman, N2 adsorption-desorption, ESEM and H2-TPR And other means were used to characterize the structure of the composite oxide and its performance in the catalytic oxidation of Cl2 to Cl2 was also investigated.The results show that the doping of Cu, Cr and Zr can significantly reduce the grain size of the composite oxide, Oxide surface area and pore volume, and provide more low temperature reducible oxygen species.While La and Ti doping can obtain larger surface oxygen vacancy concentration and increase the number of high temperature reducible oxygen species.Composite oxide structure and The change of surface properties significantly affected the catalytic activity of HCl. The activity sequence of cerium-based composite oxide catalysts at 430 ℃ was Ce0.9Cu0.1O2> Ce0.9Cr0.1O2> Ce0.9Zr0.1O2> Ce0.9Ti0.1O2 > Ce O2> Ce0.9La0.1O2, the number of low temperature reducible oxygen species is directly related to the activity of the catalyst.The reaction kinetics test shows that the low temperature reducible oxygen species of the catalyst favors the adsorption and activation of HCl on the catalyst surface, while the oxygen vacancy Can promote the adsorption and activation of oxygen molecules.