核壳结构梯级功能加氢脱硫催化剂的构筑及催化机制研究

The complete removal of 4,6-dimethyldibenzothiophene has became the development bottleneck for the clean and full conversion and ultilization of medium and low temperature coal tar. The key to break this development bottleneck is to break the thermodynamic limitation of the hydredesulfurization for 4,6-DMDBT and to enhance the selectivity of direct desulfurization route. Thus, we will employ the constructing of TiO2-Al2O3@TS-1 materials with different TiO2/Al2O3 ratio and different thickness of the TiO2-Al2O3 composite oxide shell as strategy, through the hierarchical depositing of active metals to construnct the core-shell hierachical functional hydrodesulfurization catalyt, to investigate the influences of the interaction between the active metals and the supports and the matching of hydrogenation activity and hydrolysis activity on the structures of both crystal defeciency and electron caves for the Corner active sites and the formation of Corner active sites over the hydrodesulfurization catalyst, to uncover the essence for the interaction between the active phase and the organosulfur compounds, futher to develop the hydrodesulfurization mechanism of refractory organosulfur compounds over the Corner active sites. To propose the technology for designing and preparing of the hierachical functional hydrodesulfurization catalyst that mathches the step-by-step conversion characteristics of highly refractory organosulfur compounds. To provide the experimental supports and lay the theoretical foundation for ultra-deep hydrodesulfurization on the premise of maintaining the high aromatic hydrocarbons for medium and low temperature coal tar.

4,6-二甲基二苯并噻吩（4,6-DMDBT）类硫化物的高效脱除已成为制约中低温煤焦油轻馏分高效清洁转化利用的发展瓶颈。突破这一瓶颈的关键是要突破4,6-DMDBT类硫化物加氢转化的热力学限制，提高加氢脱硫催化剂的直接脱硫路径选择性。为此，本项目以构筑不同壳层TiO2/Al2O3比、不同壳层厚度的核壳结构TiO2-Al2O3@TS-1材料为策略，通过活性金属的梯级担载构筑核壳结构梯级功能加氢脱硫催化剂，分析催化剂金属与载体间相互作用及加氢/氢解匹配性对Corner位活性位的晶体缺陷及电子空穴结构的影响。探索加氢脱硫催化剂上Corner位活性位的形成机制，揭示活性相与硫化物作用的实质，发展Corner位活性位上复杂结构硫化物的催化转化机理。形成与复杂结构硫化物分步转化特点匹配的梯级功能加氢脱硫催化剂的设计基础与制备技术。为在保持高芳烃含量的前提下实现深度加氢脱硫奠定理论基础并提供实验支撑。

本课题面向我国能源化工领域“双碳”目标，立足我国能源化工主战场，基于碳基能源资源高效转化与利用，直面4,6-二甲基二苯并噻吩（4,6-DMDBT）类硫化物的高效脱除已成为制约中低温煤焦油轻馏分高效清洁转化利用这一发展瓶颈。突破这一瓶颈的关键是要突破4,6-DMDBT类硫化物加氢转化的热力学限制，提高加氢脱硫催化剂的直接脱硫路径选择性。.为此，本工作首先结合溶剂挥发自组织法和水热合成法构筑了不同壳层TiO2/Al2O3比、不同壳层厚度的核壳结构TS-1@TiO2-Al2O3材料，通过活性金属的梯级担载制备了核壳结构梯级功能加氢脱硫催化剂，并对制备的载体材料与催化剂的理化性质进行了深入研究。运用第一性原理通过密度泛函理论量子化学计算分析了催化剂金属与载体间相互作用及加氢/氢解匹配性对Corner位活性位的晶体缺陷及电子空穴结构的影响。分别从实验和量子化学计算两个方面探索了加氢脱硫催化剂上Corner位活性位的形成机制，揭示了活性相与硫化物作用的实质，发展了Corner位活性位上复杂结构硫化物的催化转化机理。揭示了磁性助剂对活性相形成及其结构的影响规律，阐明了复杂结构硫化物在边位活性位、角位活性位上的催化转化机制。基于复杂结构硫化物梯次转化的特性，分别制备了适用于复杂硫化物加氢转化的介孔NiMo/TiO2-Al2O3催化剂、梯级孔NiMo/TS-1催化剂及NiMo/TS-1@TiO2-Al2O3催化剂，通过对载体材料进行后处理及掺杂ZrO2的方式阐明了复杂结构硫化物分步转化特点匹配的梯级功能加氢脱硫催化剂的设计基础并形成了高直接脱硫选择性加氢脱硫催化剂的设计思想与制备技术。为在保持高芳烃含量的前提下实现劣质馏分油深度加氢脱硫奠定了理论基础并提供了必要的实验支撑，相关研究成果对破解我国能源化工领域低碳化、清洁化、多元化可持续发展难题具有重要意义。