FCC燃油脱硫用Bi系光催化材料构筑及脱硫机理的热化学

Semiconductor photocatalytic oxidation is one of newly-developed deep desulfurization techniques. However, due to low selectivity of the desulfurization catalysts used the unsaturated hydrocarbons in FCC fuel oil can be readily oxidized and thereby decrease the quality of petroleum products. Hence it is an enormous challenge or a research bottleneck for the desulfurization by using photocatalysts. Based on previous reports and our researches, the present project will mainly focus on the rational design, fabrication and controlled microstructure of the complicated Bi-based multicomposite catalytic materials. Some advanced strategies that can change physical-chemical property of composite materials such as the element doping, noble metal deposition and surface modification, as well as coupling with semiconductor heterojunctions, will be employed to broaden the light-responsive range, improve the utilization of sunlight and quantum efficiency of photocatalytic performance, and enhance the selectivity of photoxidation desulfurization. The information and data of heat flow curve obtained via calorimetry method can be used to investigate the synthesis mechanism of the Bi-based multicomposite photocatalysts. Chemical thermodynamics theories and methods will be used to analyze the calorimetry graphs of thiophene (T) and benzothiophene (BT) obtained from the desulfurization process. Also, according to the information and data of thermodynamics and kinetics obtained by theoretical calculation and combination with in-situ ESR, FS spectrum and HPLC-Mass analysis the mechanism of photocatalytic desulfurization process can be explored in detail. On the basis of the association of the structural characterization of catalysts and the desulfurization mechanism, the structure-activity (photocatalytic efficiency) relationships will be established for the photocatalytic desulfurization, and thereby provide the scientific basis and experimental support for the applications of photocatlytic oxidative desulfurization technology in the production process of clean fuel oil.

半导体光催化氧化是一类新兴的深度脱硫技术，然而，由于脱硫催化剂低的选择性，使得在FCC燃油中不饱和烃易被氧化而导致油品品质降低, 这成了脱硫用催化剂研究的主要挑战和瓶颈。基于先前的文献报道及我们的前期研究，本项目主要聚焦在基于Bi系多组分复合催化材料的合理设计、构建及微观结构调控，采用掺杂元素、贵金属沉积和半导体异质耦合等改性修饰策略，着意拓宽催化剂的光谱响应范围、提高太阳光利用率/光催化的量子效率和光催化氧化的选择性；通过量热学方法，获得材料合成过程的热流曲线，解析其合成机理；根据化学热动力学理论与方法解析FCC燃油中噻吩（T）和苯并噻吩（BT）类物质脱除过程的量热图谱，计算得到光催化过程的热力学/动力学数据和信息，结合原位ESR、FS光谱及HPLC-Mass分析，探究其催化机理。关联催化剂的结构和脱硫机理，建立构效关系，为光催化氧化技术在清洁燃油生产过程中的应用提供科学依据和实验支持。

半导体光催化氧化是一类新兴、理想的燃油深度脱硫技术，然而，由于脱硫催化剂低的选择性，使得在催化裂化燃料油（简称FCC燃油）中不饱和烃易被氧化而导致油品品质降低，这成了脱硫用催化剂研究的主要挑战和瓶颈。因此，构建高性能和高选择性的光催化材料是实现高效燃油深度脱硫的关键。Bi系催化材料因具有无毒、光催化活性高和稳定性好等优点，成为光催化领域研究的热点。然而由于存在光生载流子复合率高、太阳能转化效率低和难以回收再利用等缺陷，严重阻碍其实用化和产业化进程。为解决上述关键科学问题，本项目重点围绕Bi系多组分复合催化材料的合理设计、构建及微观结构调控，采用表面修饰和半导体异质耦合等改性策略开展了系统研究，着意拓宽催化剂的光谱响应范围、提高太阳光利用率/光催化的量子效率和光催化氧化的选择性。通过实验与理论计算相结合的研究方法，主要完成了以下工作：（1）结合多种制备方法，设计和构建了多种高效、稳定性和循环再利用的新型Bi系复合光催化材料；（2）结合先进表征技术和理论计算，探究了材料的能带结构、表面微结构对其电荷传输、光催化性能之间的影响机制；（3）通过量热学方法，获取FCC燃油中噻吩类物质脱除过程的量热图谱，归纳光催化剂对含硫化合物脱除过程的热/动力学机制；（4）针对FCC燃油深度脱硫（噻吩、苯并噻吩和二苯并噻吩）、无色有机污染物（苯酚）、抗生素（盐酸四环素）和还原Cr（VI）体系，进行系列可见光催化实验，阐明了催化剂的结构与催化反应活性之间的构效关系，并且探究其催化机制。项目研究成果将为构建新型高效、高选择性和高稳定性的Bi系催化材料体系提供科学依据和实验支持。. 在项目实施期间，以第一作者/通讯作者在Appl. Catal. B: Environ., Chem. Eng. J., J. Catal., Chin. J. Catal., Chem. Eur. J., Appl. Surf. Sci.和无机化学学报等国内外期刊上发表19篇，授权中国发明专利8项，培养硕士研究生7位和联合培养博士研究生1位，多次受邀参加国内外光催化相关学术会议，项目负责人入选陕西省“特支计划”区域创新发展人才（2020年）。本项目基本完成了计划书上规定的研究任务，达到了预期的研究目标。