采用柠檬酸络合法制备了CexTi1-xO2固溶体,以其为载体浸渍硝酸钴溶液制备负载钴催化剂mCo/CexTi1-xO2-T-y。考察了Co负载量(m)、载体中Ce/(Ce+Ti)摩尔比(x)、载体制备过程中柠檬酸用量(y)以及载体的焙烧温度(T)对该系列催化剂催化甲烷部分氧化(POM)制合成气反应性能的影响。利用X射线粉末衍射(XRD)、H2-程序升温还原(H2 -TPR)、扫描电子显微镜(SEM)和热重(TG)分析手段对mCo/CexTi1-xO2-T-y催化剂进行了表征。结果表明,当负载Co的质量分数为20%、柠檬酸/(Ce+Ti)的摩尔比为1、载体焙烧温度为700℃时,制备的20Co/Ce0.5Ti0.5O2-700-1催化剂对POM反应表现出优良的催化性能,其主要原因是,载体之间形成的Ce-Ti固溶体能够一定程度上抑制非催化活性相CoTiO3的生成。
A series of CexTi1-xO2 solid solutions were prepared by citric acid complex method. Then the as-synthesized CexTi1-xO2 solid solutions were used as the supports and Co with different contents were loaded by impregnating method, producing Co supported mCo/CexTi1-xO2-T-y catalysts. The effects of Co content (m), Ce/(Ce+Ti) molar ratio in support(x), the used amount of citric acid(y), and the calcination temperature (T) on the catalytic performance of mCo/CexTi1-xO2-T-y in partial oxidation of methane (POM) to synthesis gas were investigated. Some techniques, such as X-ray diffraction(XRD), temperature programmed reduction(TPR) of H2, scanning electron microscopy(SEM) and thermogravimetry analysis (TG) were used to characterize the fresh and reacted catalysts. The results showed that the catalyst(20Co/Ce0.5Ti0.5O2-700-1) with Co loading of 20%, the citric/(Ce+Ti) molar ratio of 1 and the support calcination temperature of 700℃ exhibited the excellent catalytic performance in POM reaction. The high catalytic performance could be attributed to that the formation of Ce+Ti solid solution could effectively restrain the generation of non-active component of CoTiO3.