加氢脱硫、脱芳烃沸石负载金属催化剂制备与性能研究

Nowadays dense fog haze hangs persistently over most cities in China. Hazardous particulates in automobile exhaust account for a major part of the pollution. High-performance supported metal catalysts are required immediately for deep desulfurization and dearomatization of fuel oil. For conventional zeolite-supported metal catalysts, the metal loading is low, and most often the metallic clusters are polydisperse and located primarily on zeolite surface, making them susceptible to poisoning and sintering. The understanding of melting and sintering behavior of nano-scale metals is still limited. Moreover, because the nanostructure, morphology, size and size monodispersity, composition and phase of loaded clusters can not be controlled simutaneously, the intervening multivariate factors make it challenging to explore catalysis mechanisms and burdensome to screen the catalysts. The proposed work, first, will synthesize a series of monodisperse metallic nanoparticles with well-controlled size, composition, phase and crystallinity. We will then fabricate various mesoporous zeolites by a novel self-assembly technique we developed. The hierarchical meso-micro structure improves the mass transport of reactant and product molecules within zeolites, while unique properties of zeolites such as micropore regularity, high surface area, shape selectivity, adjustable surface properties and hydrothermal stability are maintained. Monodisperse metallic nanoparticles with varying size, phase and composition will be dispersed uniformly within microporous zeolite matrix by our newly developed technique. The micropores block big toxicants such as thiophene and its derivatives. The model catalysts will be studied on two co-occurring reactions, hydrodesulfurization of 4,6-Dimethyldibenzothiophene (4,6-DMDBT) and toluene hydrogenation, in an effort to lower the emission of PM2.5 and NOX in the exhaust gas. The research will elucidate the structure/activity relationship, nano-metal size effect, synergy effect, metal-oxide and metal-metal interaction. The model catalysts will also be examined on their sulfur resistance and desulphurization. CoMo、NiMo etc nanoalloys with well-controlled size, phase and composition will be dispersed selectively within the mesopores of the model catalysts by two-step self-assembly to verify feasibility of co-occurring 4,6-DMDBT hydrodesulphurization and toluene hydrogenation by the bifunctional zeolite-supported metal catalyst. The study and the concept developed in the project could lead to development of new and improved catalysts for steam reforming for hydrogen, alkane dehydrogenation, hydrogenation, CO oxidation and isomerization etc.

如今，国内许多城市雾霾长期笼罩，开发高性能负载型金属催化剂用于燃料油深度脱硫、脱芳烃已迫在眉睫。常规沸石负载金属催化剂制备方法往往存在金属分散度低、负载量小、多集中于沸石外表面、易烧结、易硫中毒等难题。由于很难同时控制所载金属结构、形貌、尺寸、组成、晶相及其在载体中分布，多变量错综复杂阻碍了催化机理探究及催化剂快速筛选。本项目在前期工作基础上拟制备系列单分散可控金属纳米颗粒，利用自组装技术原位水热合成微-介多级孔道沸石负载金属催化剂，研究自组装过程与多级孔道结构调控，实现金属高效负载及其在沸石内可控分布，并研究甲苯加氢及4,6-二甲基二苯并噻吩加氢脱硫双效模型催化剂构效关系、尺寸效应、金属协同效应、载体与金属相互作用、耐/脱硫及抗烧结性能。实施本项目将建立多级孔道沸石负载金属双功能催化剂制备方法，揭示负载纳米金属的烧结规律，为催化剂快速筛选以及设计高性能沸石负载催化剂提供理论及实验依据。

如今，国内许多城市雾霾长期笼罩，开发高性能负载型金属催化剂用于燃料油深度脱硫、脱芳烃已迫在眉睫。常规沸石负载金属催化剂制备方法往往存在金属分散度低、负载量小、多集中于沸石外表面、易烧结、易硫中毒等难题。由于很难同时控制所载金属结构、形貌、尺寸、组成、晶相及其在载体中分布，多变量错综复杂阻碍了催化机理探究及催化剂快速筛选。我们开发出反相微乳原位合成法制备系列单分散可控金属纳米颗粒，利用自组装技术原位水热合成微-介多级孔道沸石负载金属催化剂，研究自组装过程与多级孔道结构调控，实现金属高效负载及其在沸石内可控分布，取得了一系列成果，此外，通过在原位一步法基础上制备高分散、高活性、高循环性能的Ni-MoS2/C的HDS催化剂。通过水热法合成多维花簇状纳米MoS2，通过调节前驱液的浓度调节MoS2的尺寸，具有很好的HDS性能，采用原位合成技术，将药物和农药分散于适当溶剂内，随后采用亲油或者亲水的纳米材料在药物表面包裹形成膜，形成亲水亲油可调的缓释纳米胶囊。制造出“绿色农药”。该产品已获得下游产品的好评，因此，基于本项目所提出的这种合成方法，在材料合成与相关技术运用领域有很好的应用前景。