稀土盐-氧化物复合催化剂的构建及高湿环境催化氧化二氯甲烷的抗氯机制研究

With the continuous advancement of air pollution control in China, the development and optimization of terminal control technology has become the focus of VOCs control at this stage. Aiming at the problems of catalyst chlorine poisoning and toxic by-products formation in catalytic combustion of chlorinated VOCs, this project explores technical ways to solve these problems by taking advantages of reaction atmosphere. Based on the construction of rare earth salt-oxide composite catalytic system, the mechanism of chlorine dissociation and desorption accelerated by water vapor was studied. The effect of rare earth salt structure on chlorine desorption process was investigated from the aspects of structure-activity relationship and reaction mechanism. The migration and transformation mechanism of water and chlorine species in the reaction process was explored by in situ characterization technology and molecular simulation. In combination with the effects of catalyst interface on deep oxidation, the anti-chlorine poisoning mechanism of rare earth salt-oxide system in high humidity environment is proposed, which would provide experimental and theoretical support for improving the existing industrial CVOCs catalytic combustion technology. The key problems to be solved are the effects of rare earth salts on hydrolytic dechlorination of CVOCs and the pathway of water molecules participating in chlorine desorption in the reaction system.

随着我国大气污染控制工作的不断推进，末端控制技术开发及应用成为现阶段挥发性有机物（VOCs）治理工作的重点。本项目针对含氯VOCs在催化燃烧过程中存在的催化剂氯中毒及毒副产物生成问题，探索通过应用反应气氛调控解决上述问题的技术途径。基于稀土盐-氧化物复合催化体系的构建，研究水汽加速催化剂表面氯解离脱附机制，从构效关系与反应机理着手，考察稀土盐结构对氯脱附过程的影响；利用原位表征技术与分子模拟，探究反应过程中水与氯物种的迁移转化机制；结合组分界面对深度氧化过程的影响，分析高湿环境稀土盐-氧化物体系的抗氯中毒机理，为完善现有工业含氯VOCs催化燃烧技术提供实验及理论支撑。项目拟解决的关键问题包括稀土盐对含氯VOCs水解脱氯的影响以及反应体系水分子参与氯解吸的路径研究。

随着我国大气污染控制工作的不断推进，推进VOCs末端控制技术的开发及应用成为现阶段挥发性有机物（VOCs）治理工作的重点。本项目针对含氯VOCs（CVOCs）在催化燃烧过程中存在的催化剂氯中毒及多氯副产物生成问题，探索了利用反应气氛触发水解路径加速氯物种脱除的技术策略，提出了基于构效关系改善催化剂综合性能的多活性中心设计思路。基于磷酸镧-氧化铈复合体系的构建，考察了水汽加速催化剂表面氯脱附的可行性，明晰了磷酸镧结构对脱氯过程的影响；结合组分、界面的影响， 提出了改善CVOCs综合催化性能的多活性中心催化剂设计思路；构建了在无水或高湿条件下同时具备高活性、高选择性、高稳定的三元活性中心催化剂，明确了HZSM-5酸性吸附、CeO2空位活化、Ru氧化脱氯的三元协同机制，有效减少了多氯副产物的生成，提高了催化剂在复杂工业烟气条件下的抗性与广谱性。该内容为进一步将理论基础研究推及至工业应用场景，克服在多组分VOCs催化燃烧过程中催化剂氯中毒与二次污染等瓶颈问题提供了有效的实验及理论支撑。