稀土基催化剂上含氧、含氯挥发性化合物低温催化消除研究

The volatile organic contaminants (VOCs), as the emissions from various industrial processes often characterized with high concentrations varying in the complicated compositions, can cause the problem of atmosphere pollution, especially the pollution by the VOCs containing heteroatoms that has not yet raised the sufficien t concern and attention in our country. In this project, model reactions are assumed in terms of catalytic elimination of those most detected VOCs in industries that contain heteroatoms such as oxygen and chlorine; based on the typical emission conditions in industries, kinetic characteristics and reaction mechanism of the oxidation process of heteroatom-containing VOCs are analyzed. With the above intentions, a series of Ce-base nano composite catalysis materials modified by transition metals or rare earth oxides are designed and prepared with the features of controllable morphology as well as structure. In the study of catalysis materials, modern characterization means and theoretical computations are employed in the research of the law regulating the action between the d electrons of the transition metal and 4f vacant orbit of Ce on the surface of the energy -discrete CeO2 particle (quantum effect), in order to obtain various optimized high-performance catalytic oxidation systems that combine the multi- activity centers with the synergistic effect. These oxidation systems, involving the integration of the following processes such as activation and disruption of the bonds between carbon at oms and heteroatoms, oxidation of carbon species, protonation of chlorine species and hydrolysis, convert heteroatom-containing VOCs into the products of CO2、H2O、N2 meeting the emission requirements. Finally, novel technology, new principle and method are proposed for elimination of the pollution problem caused by the heteroatom-containing VOCs.

挥发性有机污染物（VOCs）的工业排放源头多、强度高、成分复杂多变，由此引起的大气污染问题，尤其是含杂原子VOCs污染问题在国内还没有引起足够高的重视和关注。本项目以工业上检出频率最高含氧、含氯杂原子VOCs的催化消除为模型反应，以工业上典型排放工况为条件，分析含杂原子VOC氧化反应过程的动力学特征与反应机理，设计和研制一系列形貌或结构可控的过渡金属和稀土氧化物等修饰的Ce基纳米复合催化材料；通过含杂原子VOCs催化消除机理、高温耐酸耐湿催化新材料的形成机制、在催化消除过程中二次污染毒性副产物生成与控制机制等等的研究，优化出多种活性中心结合协同作用的高性能催化氧化体系- - 碳与杂原子键的活化和断裂、碳物种的氧化、卤素物种的质子化、水解等多种过程一体化――将含杂原子VOC转化成CO2、H2O、N2等合乎环境要求的产物，提出杂原子VOCs污染催化消除的新技术、新原理和方法。

挥发性有机污染物（VOCs）引起的大气污染问题，尤其是含杂原子VOCs污染问题在国内还没有引起足够高的重视和关注。本项目以工业上检出频率最高含氧、含氯杂原子VOCs的催化消除为模型反应，以工业上典型排放工况为条件，分析含氯原子VOC氧化反应过程的动力学特征与反应机理，设计和研制一系列形貌或结构可控的过渡金属和稀土氧化物等修饰的Ce基纳米复合催化材料，包括Ru、Ti、V、W、Al等多层次修饰的氧化铈纳米材料；通过含氯原子VOCs催化消除机理、高温耐湿催化新材料的形成机制、在催化消除过程中二次污染毒性副产物生成与控制机制等等的研究，优化出多种活性中心结合协同作用的高性能催化氧化体系- - 碳与氯原子键的活化和断裂、碳物种的氧化、氯物种的质子化、水解等多种过程一体化，即由B酸和L酸、氧化还原性和表面氧可得性多种功能的集合――在低温高空速的条件下，将含氯原子VOC转化成CO2、H2O、HCl等合乎环境要求的产物。在氯代芳香烃类浓度为500-6000 ppm、体积空速为60000h-1的条件下，90%的转化温度为320oC以下；HCl和CO2的选择性高于90%；在相同的条件下，氯代脂肪烃和烯烃90%的转化温度为300oC以下，HCl和CO2的选择性高于95%。Pt修饰的Ce基纳米催化剂能够耐受5%（体积）。各系列催化剂均表现出良好抗氯中毒稳定性，在100-1000小时内，保持较高的稳定活性。在Ce基纳米复合催化材料上的含氯原子VOCs催化消除提出新反应机理。