重油残渣基富氮多孔石墨烯复合材料的可控制备及其作为光伏电极的研究

Owing to their low cost, extensive source and high carbon content, heavy oil residues show tremendous potential as ideal carbon sources for industrial synthesis of various kinds of high value-added new carbon materials. On the other hand, attributed to its unique physical and chemical properties, graphene, especially nitrogen-enriched porous graphene, has been attracting great potential applications in many research fields. However, to date, controllably synthesize high performance nitrogen-enriched porous graphene materials from heavy oil residue in large scale is rarely reported. In this project, graphitic carbon nitride (g-C3N4) is elaborately selected as a self-sacrificial template due to its high nitrogen content and easily decomposed feature. More importantly, the high level of pyridine-like nitrogen in g-C3N4 provides rich electron lone pairs to capture metal ions, which will enhance the graphitization and catalytic activity in the following treatments. Therefore, based on the using of g-C3N4/M (such as Co, Fe and Ni) as templates and catalysts, we have developed a new method to controllably produce high-quality nitrogen-enriched porous graphene composite materials from the cheap heavy oil residues. The formation mechanism will be studied in details. Besides, we will further investigate the performance of the as-obtained products as counter electrodes for dye-sensitized solar cells. Here, the applicant aims to resolve the involved problems during the fabrication of carbon materials from heavy oil residues, including the inhomogeneity of doping, low doping level and complicated template removal treatments. This proposed study will be helpful to realize the low-cost and controllably converting heavy oil residue into high performance nitrogen-enriched porous graphene composites in large scale, and it will also open up new avenues for their high value-added utilization.

重油残渣因其成本低、来源广、含碳量高等优点被认为是工业化生产各种高附加值新型碳材料的潜在理想原料。石墨烯，特别是富氮多孔石墨烯具有独特而优异的物理和化学性质，在众多领域中展现出了巨大的应用前景。但目前有关利用重油残渣可控制备富氮多孔石墨烯类材料鲜有报道。本研究拟以富含稠环芳烃的重油残渣为碳源，介孔氮化碳（g-C3N4）为模板，并利用模板表面丰富的氮原子来配位锚定过渡金属粒子M（Co、Fe、Ni等），深入开展高性能（高导电性、高表面积及高催化活性）重油残渣基富氮多孔石墨烯复合材料的制备规律研究，并探究其在太阳能电池对电极材料中的应用。本研究预期将解决重油残渣转化为功能碳材料的过程中杂原子掺杂不均、掺杂量低以及后续模板的繁琐去除问题，从而实现重油残渣基富氮多孔石墨烯复合材料的低成本可控制备，并促进其在太阳能电池领域的高附加值综合利用。

重油资源高效定向转化为高附加值碳材料是国家新材料领域的发展需求，开发高性能碳基功能材料也是目前国家急需发展的新材料。本项目围绕重油资源衍生高性能碳材料的制备及其应用研究开展工作，开发了以氮化碳为模板剂，利用原位孔结构构筑及功能一体化设计策略，实现高性能重油残渣基富氮多孔碳复合材料的可控制备，从而建立和发展一种低成本、高效及可控转化重油残渣为功能性碳材料的新技术。研究了高性能重油残渣基富氮多孔碳复合材料在染料敏化太阳能电池对电极中的应用，光电转化效率达到了7.91%，从实验和理论上揭示碳基电极材料表面活性位点对I3-电催化性能的影响，构建出材料制备与电池性能之间的关系。为了拓宽材料的应用范围，实现重油资源材料的高附加值利用，本项目进一步探索了重油残渣基碳材料在电化学储能材料以及电磁波吸收功能材料领域的应用研究，实现了重油衍生储能碳材料的可控构筑，材料在水系电解液中能量密度达到了12.95 Wh kg-1，此时功率密度为250 W kg-1，发展了一种高性能碳基复合电容材料的电化学调控合成新策略，揭示了材料在服役过程中的电化学动态重构演变规律；实现了石油沥青基电磁波吸收材料的构筑及应用，实现了对入射电磁波99%的吸收性能，揭示了材料内部的电磁波损耗机制，提出了低成本、批量制备“薄、轻、宽、强”电磁波吸收材料的新工艺，进一步丰富和拓宽了重油资源的高附加值利用途径。