基于配位聚合物的新型H2S选择性氧化催化剂的设计合成及其构-效关系

H2S selective catalytic oxidation technology has been of great research interest in recent decades because it can not only eliminate the highly toxic H2S gas, but also reclaim the sulfur as a new resource for other applications. The key of this technology is to develop catalyst with high performance. Typical catalytic materials with carbon-based catalysts and metal oxide-based catalysts generally suffer from the low efficiency in removal of H2S. Moreover, the reaction mechanism of these systems is still unclear. In this proposal, a new way for preparing high-efficiency H2S selective oxidation catalysts is proposed by taking the advantage of unique properties of coordination polymers. Based on the well-established principles of crystal engineering and supermolecule chemistry, a series of coordination polymer catalysts will be designed by appropriate selection of metal components and the organic linkers. In order to satisfy the realistic applications of the coordination polymer, the structure and the property of the coordination polymer will be tuned by controlling the inorganic metal ions/clusters, modifying the ligands with different substituent groups or using the specific synthesis modulators. In addition, the adsorption, activation, reaction processes of the reactants on the surface of catalysts will be investigated in detail. Based on the catalyst characterization and the catalytic performance evaluation, the internal relationships between the component, structure, and properties of the catalysts will be clarified. Furthermore, by combining with the calculation of quantum chemistry, the possible catalytic mechanisms will be proposed and established. The achieved findings can not only provide a theoretical foundation and technical source for the development of new H2S selective oxidation catalyst, but also will promote the practical industrial applications of this technology.

选择性催化氧化H2S为硫磺既能消除剧毒的H2S气体又能实现硫元素的资源化，是目前具有挑战性的研究课题，其关键在于研发高效的催化剂。本项目针对以碳材料和金属氧化物为代表的传统催化剂存在催化效率偏低和反应机理研究尚不清晰等问题，拟利用配位聚合物独特的物理化学性质发展新型H2S选择性氧化催化剂。运用晶体工程和超分子化学原理，合理搭配金属和有机配体自组装形成配位聚合物。并通过无机单元调节、有机配体修饰和引入调控剂等方法对配位聚合物的结构、活性位进行调控，实现高性能配位聚合物H2S选择性氧化催化剂的设计合成；同时利用配位聚合物精确的结构系统考察反应物分子在催化剂的吸附、活化、反应等界面过程，结合量子化学计算，阐明催化剂的构-效关系，揭示其作用机理。本研究可为发展新型H2S选择性氧化催化剂、促进H2S选择性催化氧化技术的规模应用提供实验基础和理论支撑。

针对现有H2S选择性氧化催化剂存在效率偏低和反应机理尚不清晰等问题，本项目利用配位聚合物独特的物理化学性质发展新型催化剂，并围绕催化剂构-效关系及反应机理深入研究。项目取得的主要研究结果如下：（1）制备典型的Fe基MOFs材料MIL-53(Fe)，并采用“前功能化”策略，将氨基引入到MIL-53(Fe)的结构中制得NH2-MIL-53(Fe)，首次将Fe-MOFs材料应用于H2S选择性氧化反应。综合利用各种手段研究催化剂的组成、结构及形貌，探明Fe-MOFs选择性氧化H2S的反应途径；（2）构筑具有Fe2+/Fe3+ 配位不饱和位点的MIL-100(Fe)（记为CUS-MIL-100(Fe)），CUS-MIL-100(Fe)在较温和条件下能实现H2S完全转化，S选择性接近100％。并且，该催化剂连续反应100小时活性没有明显降低，展示出高的脱硫活性和稳定性，性能优于商业Fe2O3和大多数已报道的铁基材料；（3）制备Ti基MOFs材料MIL-125(Ti)，并修饰NH2官能团得到NH2-MIL-125(Ti)。氨基功能化后的NH2-MIL-125(Ti)在H2S选择性氧化反应中展示出优异的催化活性，系统考察催化剂结构，建立了催化剂的构-效关系，并总结了MOFs脱硫催化剂氨基功能化的调控规律；（4）在Zr基MOFs（UIO-66(Zr)）结构中引入Fe组分，制备双金属Fe-Zr MOFs材料。重点考察Fe掺杂对UIO-66(Zr)结构与H2S选择性氧化性能的影响，该材料相比单金属MOFs脱硫性能明显提高。结合多种手段阐明了Fe-Zr两种活性组分的协同机制，建立该催化剂的反应机理模型，为发展高效稳定的配位聚合物脱硫催化剂奠定理论基础。. 总之，我们在项目执行期间，获得较多有价值的研究成果，发表与本项目相关的SCI论文12篇，申请国家发明专利5项。