铈基复合氧化物中晶格氧用于甲烷部分氧化制合成气

采用共沉淀法制备了Ce-M-O氧载体（M＝Fe、Mn、Cu），并进行了XRD表征。研究了Ce-M-O中晶格氧部分氧化甲烷制合成气的反应。考察了再生时间、再生温度对氧载体部分氧化甲烷性能的影响。研究结果表明， Ce-Fe-O固溶体中的晶格氧适于部分氧化甲烷制合成气。在新鲜的Ce Fe O氧载体上存在少量的强氧化物种，导致开始阶段大部分甲烷被完全氧化，然后该氧载体能均匀地释放出具有高选择性的体相晶格氧将甲烷氧化为CO和H2。通过对氧载体再生条件的控制，可以有效提高目标产物的选择性，当再生温度为850℃，再生时间为7min时， 获得了最大的CO（96.68%）和H2（97.56%）选择性，同时H2与CO摩尔比达到2.02。在无气相氧存在下，用Ce-Fe-O中晶格氧实现甲烷部分氧化制合成气的方法是可行的。

Partial oxidation of methane to syngas using lattice oxygen from ceria-based complex oxides oxygen carriers

The ceria based complex oxides oxygen carriers (Ce-M-O, M＝Fe、Mn、Cu ) were prepared by co precipitation method and their characterizations were studied by means of X ray diffraction (XRD).The reactions between methane and lattice oxygen over the complex oxides were investigated. The Ce-M-O oxygen carriers were regenerated by air oxidation at different reaction times and temperatures, and then the catalytic performances of oxygen carriers for partial oxidation of methane to syngas using lattice oxygen were investigated. The results showed that the Ce-Fe-O sample consisted of single crystal phase and its lattice oxygen was found to be suitable for partial oxidation methane to synthesis gas. There were two kinds of oxygen species in the fresh Ce-Fe-O solid solution. The stronger oxygen species was responsible for the complete oxidation of methane. Methane could be selectively oxidized to CO and H2 by the weaker oxygen specie (bulk lattice oxygen) at a higher temperature, then the lost bulk lattice oxygen could be selectively supplemented by air re oxidation at appropriate reaction conditions. Using the oxygen carrier which was regenerated at 850℃ for 7min, the selectivity of CO and H2 could reach 96.68% and 97.56% respectively and the value of H2/CO mol ratio in syngas was 2.02. In the absence of gas phase oxygen, it is possible to generate syngas using the lattice oxygen of the Ce-Fe-O to react with methane following the redox mechanism.