高效Pd基催化剂的还原构筑及其低温催化氧化VOCs研究

Catalytic oxidation is one of the effective methods for VOCs removal, and the Pd based catalyst has been widely studied for VOCs oxidation. The metallic Pd species have been recognized to exhibit good performance for VOCs oxidation at low temperature. CO, H2 and NaBH4 pretreatments are workable for obtaining the metallic Pd species. However, the reduction construction of the structure of the active sites is not clear, leading to no structure - activity relationship established and obstructing the development of high efficient Pd based catalysts. Therefore, it is necessary to study the reduction construction of Pd based catalysts. In this work, three reduction methods (H2, CO and NaBH4) will be selected to pretreat Pd based catalysts for benzenes oxidation, respectively. With the regular structure of the carriers, the active sites will be characterized to clarify the reduction construction mechanism of the pretreatments. Subsequently, the promotion mechanism of the reduction construction for catalytic performance will be clear. Then the reduction construction- active sites –activity relationship of benzenes oxidation on Pd-based catalysts will be established. In addition, the reaction mechanism of benzenes oxidation will be investigated. Finally, the key factor affecting the catalytic performance of Pd based catalysts will be confirmed to facilitate the development of high efficient oxidation catalysts for VOCs at low temperature.

催化氧化是去除VOCs最有效的方法之一，其中Pd基催化剂是研究最为广泛的催化剂体系。研究发现，金属态Pd能够使Pd基催化剂获得更好的低温氧化VOCs性能。目前H2、CO和NaBH4还原预处理对获得金属态Pd均有一定可行性，但其还原构筑的活性中心局域结构不明确，导致Pd基催化剂低温催化VOCs的构效关系迟迟未建立，阻碍了高效Pd基催化剂的发展，所以有必要研究Pd基催化剂的还原构筑。因此，本项目拟以苯系物催化氧化为模型反应，研究CO、H2和NaBH4三种不同还原方式对Pd基催化剂催化氧化VOCs的影响，借助纳米线载体的规整性，明晰预处理方式对活性中心局域结构的还原构筑规律，确立还原构筑对催化剂性能的促进机制，建立“还原构筑-活性中心局域结构-催化氧化性能”三者之间的本质联系，明确苯系物催化氧化反应机理，甄别影响Pd基催化剂催化氧化性能的关键因子，为高效VOCs氧化催化剂的制备提供指导。

催化氧化是去除VOCs最有效的方法之一，其中Pd基催化剂是研究最为广泛的催化剂体系。研究发现，金属态Pd能够使Pd基催化剂获得更好的低温氧化VOCs性能。目前H2、CO和NaBH4还原预处理对获得金属态Pd均有一定可行性，但其还原构筑的活性中心局域结构不明确，导致Pd基催化剂低温催化VOCs的构效关系迟迟未建立，阻碍了高效Pd基催化剂的发展，所以有必要研究Pd基催化剂的还原构筑。因此，本项目采用多种手段表征预处理方式和载体形貌对Pd基催化剂活性中心的价态、颗粒尺寸和暴露晶面的影响，明晰了低温高效Pd基催化剂的还原构筑规律；通过苯系物低温催化氧化反应进程的在线监测和Pd基催化剂的原位表征，初步解析低温Pd基催化剂催化氧化苯系物的反应机理，明确了还原方式和不同形貌对Pd基催化剂性能的影响规律；通过协同催化原位反应，初步明晰CO与苯系物协同催化相互作用机制，明确了影响Pd基催化剂低温催化氧化性能的关键因子，为高效VOCs氧化催化剂的制备提供指导。