负载型催化剂的表面相互作用及其在大气分子污染物NO和CO消除中的应用基础研究

负载型催化剂具有重要的应用背景,研究表面分散组分与载体之间的相互作用.对于了解催化过程的本质,进而设计开发高效实用的催化剂均有重要的指导意义.本课题组近年来在该领域中进行了一些探索研究,涉及的催化剂以负载型金属氧化物(如CuO/γ-Al_2O_3,CuO/Ce_xZr_(1-x)O_2和CuO/Ti_xSn_(1-x)O_2等)为主,涉及的反应包括CO完全氧化和NO+CO反应.通过改变活性组分的负载量、添加改性剂和改变样品制备条件等制得一系列样品,用多种固体催化剂表征手段考察各组分在催化剂中的作用以及在上述催化反应中的活性变化规律.研究表明:(1)金属氧化物和卤化物等离子化合物在氧化物载体表面的分散容量和分散后的一些性质均可从"嵌入模型"的考虑得到解释;(2)处于不同载体表面的活性物种或同一载体表面不同结构的活性物种,由于其存在状态的差异使得其氧化还原性质和催化性质不同;(3)在相关催化剂体系中进行的CO完全氧化和NO+CO反应的结果显示,通过探索催化剂的"组成-结构-性质"间的关系,有可能为实际催化剂的设计提供理论参考.

Studies on the Surface Interaction of Supported Metal Oxide Catalysts and Their Applications in the Abatement of Air Pollutant Molecules NO and CO

Supported catalysts are widely used in industry and in academic research, and the investigation of the interaction between the dispersed surface components and supports is key to the understanding of the nature of catalytic reactions and the design and development of effective and practical catalysts. This review summarizes some results of our group in this field. The related catalysts include supported metal oxides such as CuO/γ-Al_2O_3, CuO/Ce_xZr_(1-x)O_2, and CuO/Ti_xSn_(1-x)O_2, and the reactions are mainly focused on the CO oxidation and NO + CO reaction. These mentioned catalysts, prepared by adjusting the Ioadings of active species, introducing modifiers, and changing preparation conditions, are characterized by normal measurements for solid catalysts in order to explore the functions of each component and monitor the variation of activity in the reactions. It is shown that: (1) the dispersion capacity of metal oxides or halides on the surface of oxide supports and some of their properties can be explained on the basis of the "incorporation model"; (2) the dispersed active species on the different supports or the dispersed active species with different structures on the same support exhibit different redox and catalytic properties, which are resulted from the diversity of tbeir existing states; (3) the results obtained from CO oxidation and NO + CO reactions proceeding on the associated catalysts indicate that it is possible to design catalysts by exploring the relationship among "composition-structure-property".