催化碳纤维材料低温选择性氧化脱硫及调控规律

The control and treatment of air pollution are the major and urgent issue in sustainable development of economy and society. The desulfurization of fuel oils attaches great importance to enhance the quality of fuel quality and improve the atmospheric environment. At present, the sulfur of mercaptans have been efficiently removed by extractive type processes such as Merox process employing sulfonated cobalt phthalocyanine as the catalyst in petrochemical industry, however, it is frustrated in hydrodesulfurization of organic sulfur compounds such as benzothiophene (DBT) and 4,6-Dimethyldibenzothiophene (DMDBT). Therefore, great breakthroughs in theory and application are highly desired to be made for efficiently deep desulfurization. In this project, the bioinspired catalytic system will be developed by simulating the structure and function of metal porphyrin-based cytochrome P450 and horseradish peroxidase HRP, in which the efficiently oxidative removal of sulfur in DBT and DMDBT could be achieved under mild conditions. Carbon fiber material has excellent mechanical, electrical and physical and chemical properties, and presents special catalytic properties that the traditional inorganic carrier material does not exhibit. Based on the large specific surface area and the unique π-electron conjugated characteristics of carbon fibers, we will prepare carbon fiber material-supported metallophthalocyanine (MPc) by the coordination bond to obtain the biomimetic catalytic carbon fiber materials. In addition, we will explore the mechanism and principles of multiple regulating-control in substituents and the fifth axial ligand to MPc, the type of supporting carbon materials and the bonding mode between MPc and carbon materials, etc. Further, the structure-activity relationship and catalytic mechanism will be studied in-depth. This bioinspired strategy could provide the new methods and ways for selectively catalytic oxidation deep desulfurization at low temperature. This research is to provide scientific foundation for efficient and deep desulfurization of fuel oil and will make efforts to achieve the source treatment of atmospheric environment.

大气污染控制与治理是维持经济社会可持续发展最迫切需要解决的重大课题，其中油品脱硫是燃油品质提升和大气环境改善的重要途径。目前，石油加工中广泛采用磺化钴酞菁实现硫醇的高效脱除，但对二苯并噻吩（DBT）和二甲基二苯并噻吩（DMDBT）等还原加氢难度较大的含硫化合物效果较差，必须在理论和应用研究上有所突破。本项目通过模拟自然界中具有金属卟啉中心的细胞色素P450 和过氧化物酶的结构和功能，构建低温选择性氧化噻吩类硫化合物的仿生催化体系。由于碳纤维材料具有优异力学、电学和物理化学性能，有着传统无机载体材料不可比拟的催化特性，项目利用其比表面积大及表界面独特的π电子共轭特性，设计制备碳纤维材料配位键合金属酞菁的催化碳纤维材料，探索对金属酞菁取代基团、轴向第五配体及其键合方式等进行调控的理论基础与影响规律，揭示高效脱除DBT、DMDBT的构效关系与催化机理，建立低温选择性催化氧化脱硫的新方法和新途径。

针对由汽车尾气排放的氧硫化物造成的污染问题，环保部已经规定车用汽油和柴油中的硫含量必须低于10ppm。对于燃油中含硫化合物，吸附脱硫、萃取脱硫、加氢脱硫的技术很难实现深度脱硫。氧化脱硫技术是近年来发展起来的一类高效消除燃油中噻吩类硫化物的技术，且相对来说能耗低、污染小、操作简单。本项目设计构建低温选择性氧化噻吩类硫化合物的仿生催化体系，以金属酞菁作为催化活性中心。采用不同方法将其负载到具有易修饰和易调控等特点的碳纤维或者碳纳米管上制备得到系列复合催化剂，通过调节不同的反应参数确定最佳条件，并且深入分析了仿生催化脱硫体系的催化机理以及DBT的氧化历程。项目通过构建仿生催化体系对DBT进行选择性氧化作用，在温和条件下就能对燃油中含硫化合物深度脱除。此外，探究了催化体系活性增强机制与多重调控原理，为仿生催化体系的构建和燃料油中的深度脱硫提供新思路，并促进仿生材料学科与环境、催化等多学科的交叉融合。