碳氮骨架限域金属硫化物活性相的精准构筑与高选择性加氢脱硫反应路径调控机制

Transition metal sulfides catalyst with excellent hydrodesulfurization (HDS) performance is widely used in the clean gasoline production. However, the saturation of olefins could not be avoided in ultra-deep HDS process over the traditional CoMo catalyst, leading to the serious loss of RON. It could be ascribed to that the controllable construction of active phase and the expected type of active sites could be achieved. The catalysts of oxidation state are usually prepared with the impregnation of the transition metal oxysalts. Due to the complicated composition of the impregnation solution, there are many indistinguishable transition metal species on the surface of the catalyst, which is detrimental to the study on the sulfiding construction mechanism of the active phase. In this study, several Co-Mo polyoxometalates would be prepared as the nucleus to obtain the composite material with bimetallic organic frameworks as shell (POMs@MOFs). Furthermore, transition metal sulfides by confined N-doped carbon matrices with single structure was obtained through regulated sulfidation process. Based on the model catalyst with single structural morphology of the CoMoS nanoparticle, the adsorption, reaction and desorption process of the sulfides and olefins would be comprehensive studied, as well as the kinetics of selective HDS reactions. The research results are valuable for illuminating the nature of the transition metal sulfides active phase, and the structure-activity relationship between the active phase morphology and the catalytic performance, as well as the controlled production mechanism of the active site, which are useful for the development of catalysts with high catalytic performance in selective HDS of FCC gasoline.

过渡金属硫化物催化剂广泛用于加氢过程生产超低硫清洁汽油。现有钴钼加氢脱硫催化剂在深度加氢脱硫的同时不可避免的产生烯烃加氢，造成辛烷值损失，其根本原因在于对于活性相纳米结构的硫化构建及特异活性位的选择性构筑缺乏清晰的认识和有效的控制策略。由于常规催化剂制备所采用的浸渍液组成复杂，催化剂表面存在众多难以区分的金属活性物种，不利于活性相纳米结构的控制构建和催化反应机理的研究。因此，本课题设计组装特定分子结构的钴钼杂多酸簇（POMs），并以此为核制备金属有机框架包覆POMs的核壳复合材料，控制硫化过程实现碳氮骨架限域的单一结构硫化物活性相的精准构筑，并开展加氢脱硫和烯烃加氢反应规律和催化作用机理研究。从而揭示过渡金属硫化物活性相纳米结构的硫化构建机理及高选择性加氢脱硫反应路径的调控机制，阐明活性相纳米结构与加氢脱硫活性和选择性的构效关系，为高性能FCC汽油选择性加氢脱硫催化剂的开发提供理论指导。

过渡金属硫化物催化剂广泛用于加氢过程生产超低硫清洁油品，设计开发活性和选择性更高的加氢脱硫催化剂是清洁油品生产技术开发的关键。本项目研究形成了层状钼基复合金属氧化物和金属有机框架物ZIF-8包覆CoMo复合材料的控制合成方法；构筑了多孔碳包覆的具有不同结构的过渡金属活性相，揭示了活性相微观组成结构与加氢脱硫反应路径的调控机制，深入认识了活性金属Co与Mo间的协同作用规律；发展了活性组分硫化过程控制构建活性相微观结构的机理，阐明了活性相微观结构与加氢脱硫活性和选择性的构效关系，可为高性能加氢脱硫催化剂的开发提供理论指导。此外，拓展预硫化方法制备了油溶性钼基催化剂，可自硫化分解形成纳米级分散的活性金属纳米簇，表现出优异的渣油加氢转化性能。