二氧化铈表面氧的活化及对氧化反应的催化作用

Surface oxygen activation on CeO_2 and its catalytic performances for oxidation reactions

稀土催化材料的研究和发展为La和Ce等高丰度稀土元素的高质、高效利用提供了有效的途径.Ce基催化剂由于具有优异的储放氧性能,在氧化反应中得到广泛应用.本文介绍了采用理论模拟的方法,在研究Ce的4f轨道和结构弛豫对CeO2氧空位的形成和迁移中的作用以及作为载体时助催化作用的最新研究成果,提出了铈锆固溶体高储放氧性能的本质原因,为进一步制备高性能的氧化铈基储放氧材料和催化剂提供了理论基础.同时,对铈基催化剂在甲烷催化燃烧、CO催化氧化和卤代烃催化燃烧等反应中的应用和催化作用进行了综述,重点讨论了CeO2及其复合催化剂的氧化还原性能与其活性之间的关系.最后对在铈基催化剂研究中存在的问题和发展思路提出了思考和展望.

The research and development of rare earth catalytic materials will greatly promote the high-efficiency use of abundant rare earth elements, such as La and Ce. Based on the excellent oxygen storage/release capacity of CeO2-based catalytic materials, they have been widely used in many oxidation processes. In this paper, the recent progress of theoretical research on CeO2-based materials was reviewed, including the oxygen vacancy fbrmation/diffusion on CeO2, the promoter effect of the carrier CeO2 and the nature of high oxygen storage properties of cerium zirconium solid solution. Through the discussion of the effect of Ce 4f orbit, special electron structure and structurl relaxation on the aspects above-mentioned, the reasons for high oxygen storage performance and high oxidation activity of CeO2-based catalytic materials have been revealed. Furthermore：, the catalytic performances of CeO2-based catalysts for the catalytic combustion of methane and halogenated hydrocarbons and CO oxidation were reviewed, and the relationship between the redox properties of CeO2-based catalytic materials and their catalytic activity for these oxidations were discussed. Finally, the problems and development thinking for the： CeO2-based catalysts are put forwarded and outlooked.