煤基三维石墨烯宏观体的设计构筑及其光催化转化CO2的性能研究

The low-cost large scale production of graphene assembly materials with tuned structure and properties remains one of the challenges up to now. How to effectively utilize coal powder and to make use of this carbonaceous material to produce functional carbon materials in low cost and under controllable ways and realize the refinement conversion of CO2 is a great subject for the researchers. This proposal aims to develop techniques for making functionalized graphene assembly materials directly from coal powder in cost-effective way. The strategy of making low-cost functional graphene assembly materials from coal powder will be explored from the view points of molecular science and products process optimization. The influence of a number of parameters on the structure, surface properties and functionalities of the graphene assembly and its derived composite materials will be addressed in detail, including the coal type (with anthracite as a main or focused coal type), mineral matter/ash content, organic functional groups, volatile matter content and fixde carbon, etc. The disordered organic structure, i.e. the aromatic building structure unit (ABSU) of coal unit, will be tuned and transformed in terms of the ABSU size and functionality by using a number of techniques such as catalytic-heat-treatment, chemical oxidation ,micro-wave and hydrothermal synthesis. The mechanisms involved in these processes will be studied in much detail. The application potential of the coal-based functional graphene assembly materials in CO2 photocatalysis reduction reaction will be explored. The technologies for effectively modifying the concerned coal-based graphene assembly materials from coal powder will be developed and evaluated, including selectivein-situ supported and chemical reduction, etc. The efforts will lead to a number of patented techniques and processes for making functional graphene assembly materials from coal powder. This project will help to shed a light on the low-cost production of high photocatalysis performance functional graphene assembly materials and will pave a new way to effectively utilize the coal powder resource and CO2 concersion.

结构和性能可调变的廉价石墨烯宏观体的可控制备是一个富有挑战性的前沿课题。本项目围绕山西煤炭资源之高附加值利用及CO2资源的精细化利用之目标，从分子层面和产品工程的角度，研究并建立基于粉煤资源制备功能化石墨烯宏观体材料的新技术和新方法。诠释煤炭变质程度、煤中矿物质、有机官能团、挥发份、固定碳等参数对目标产物结构及表面物理化学性质等的影响规律；研究揭示催化热处理、化学氧化、微波及水热合成等技术对煤中芳香基本结构单元的芳香层片结构之生长、剪裁及组装的作用机制，阐明宏观体产物的结构特征与其转化反应性间的内在关系；结合CO2光催化转化过程对新结构高性能催化剂的需求，研究建立选控和定向制备煤基石墨烯宏观体及其复合材料的新技术方法和调控策略。本项目的实施，在科学层面将为创制低成本功能化煤基石墨烯宏观体及其复合材料奠定科学基础，在技术层面，将为中国粉煤的的高附加值利用及CO2的化学品转化拓展新的空间。

煤炭是自然界富存的以多环芳烃结构单元为主的含碳有机物，在新型碳材料制备中扮演着重要角色。项目以粉煤为原料，针对煤基石墨烯宏观体（3D-CG）的可控构筑及其在CO2光催化转化方面的应用进行了系统研究。重点研究了3D-CG的构筑方法及工艺条件对其结构组装和微纳织构调控的影响，探讨了影响3D-CG复合材料多尺度结构与性能的主要因素；设计并构建了气液固三相固定床光催化反应体系，考察了3D-CG及其复合材料在光催化还原CO2过程中的催化特性。.在3D-CG可控制备及其微结构调控方面，重点探究了液相组装过程中溶剂、交联剂和还原剂对3D-CG结构尺寸和强度以及表面官能团的影响。研究结果表明：煤基氧化石墨烯具有良好的凝胶化特征，以乙二胺作为还原剂进行结构组装，能够抑制石墨烯片层堆叠和体积收缩，提高宏观织构稳定性，同时实现3D-CG表面氨基功能化，有利于其二次结构调控和活性组分的原位负载修饰，促进CO2在其表面的吸附与活化。进一步通过调节溶剂热、化学浴沉积及高温煅烧等工艺方法与条件，精确调控3D-CG的表面基团及化学组成，实现多尺度纳米ZnO和g-C3N4纳米片的原位负载，得到系列不同微纳织构的3D-CG复合材料。在CO2光催化转化方面，系统研究了3D-CG及其系列复合材料的光催化性能及CO2光催化转化机制。研究结果表明：表面适度还原的3D-CG能够降低表面电荷传输电阻，同时保留部分活性基团作为催化活性中心促进光催化反应的进行；g-C3N4与纳米ZnO良好的界面接触产生的异质结，以及三维石墨烯结构作为优异的电子受体所产生的高效协同作用，使得3D-CG及其复合材料在紫外和可见光照下均表现出优越的光催化活性和稳定性。.项目的实施建立了基于低值粉煤创制微纳结构可控的石墨烯宏观体材料的新方法，探讨了3D-CG及其复合材料在CO2光催化转化过程中的作用机制，为煤炭精细高端化利用以及CO2高效转化提供良好理论支撑，丰富并发展了煤化工及石墨烯研究的内涵。