生物质基二维氮掺杂碳材料的同步构筑及其氧还原电催化特性研究

Low abundance, high price and low stability of Pt-involved electrocatalysts seriously hinder the commercialization of fuel cells. Over the past decades, the newly emerged two-dimensional (2D) carbon-based materials (e.g., graphene derivatives) have been considered as very promising alternatives for Pt-based catalysts toward oxygen reduction. In the present work, distinctively different from the traditional techniques involving catalysts, templates or substrates, a one-step growth strategy combining carbonization, etching and in-situ N-doping together, is proposed for the preparation of 2D carbon-based materials. Firstly, the resourceful biomasses are chosen as the raw materials for the facile synthesis of 2D carbon materials with tailed thickness (<2 nm), improved electronic conductivity, increased surface area, open porous structure and adjusted defect structures, through the co-pyrolysis with nitrogen-containing compounds. The research will be carried out systematically to investigate the influences of the structure characteristics of the biopolymer/nitrogen-containing species and the pyrolysis procedures on the growth and the structural regulations of 2D carbon materials, which lead to the clarification of the growth mechanism of biomass-derived 2D carbon materials, and the establishment of a general method for the controlled growth of 2D carbons. Secondly, the relationships between the defect/doping structures and the electrocatalytic activity/stability, will be investigated deeply to demonstrate the detailed catalytic mechanisms for the active sites of the as-synthesized 2D carbons. Current work might present some basic theories and key technologies to push forward the exploration of novel and highly efficient/durable cathode electrocatalysts in fuel cells, which has scientific significance and promising prospect for the practical applications of 2D carbon materials.

铂基电催化剂的资源、成本和稳定性问题严重制约着燃料电池的商业化进程。近些年迅猛兴起的以石墨烯衍生物为代表的二维碳基材料，被认为是颇具发展潜力的代铂新型氧还原电催化剂，是当前研究的热点。本项目拟突破催化剂/模板/衬底诱导生长二维碳材料的传统理念，提出集碳化/刻蚀/掺杂于一体的思路，以资源丰富的生物质为原料，采用碳/氮前驱体共热解为手段，同步构筑具有精细结构(层厚<2 nm、良好导电性、高比表面、开放多孔结构等)和缺陷可控的二维氮掺杂碳材料；然后深入研究碳/氮前驱体结构和热解工艺对二维碳材料生长的影响，揭示其同步构筑及调控机理，建立其可控制备的普适性方法，并系统探究缺陷结构对催化活性和稳定性的影响机制，阐明其活性结构的物理本质，以期获得低成本、高活性、高稳定性的燃料电池阴极催化剂。相关工作将为新颖高效碳基氧还原催化剂研发，提供一定的基础理论和关键技术，具有显著的科学意义和良好的应用前景。

以铂基贵金属催化剂为代表的氧电极材料，因成本高昂、资源稀缺、稳定性差等问题，严重限制了相关清洁能源器件的大规模商品化进程。发展高效稳定、廉价易得的非贵金属催化剂，已然成为该领域研究的重大课题之一。本项目以资源丰富的生物质为前驱体，基于碳化/刻蚀/掺杂于一体的思路，将木质素/氮前驱体共热解，构筑了层厚~1.8nm、比表面高1860m2/g、残碳率高的二维氮掺杂碳材料；深入研究了含氮前驱体结构和热解工艺对二维碳材料生长的影响，总结了二维碳基催化剂的结构演变规律，建立了宏量、低成本制备方法；以纤维素为骨架，引入并调控缺陷结构、杂原子掺杂、多孔结构、异相复合单元，系统分析了不同结构特征对电化学活性和稳定性的影响机制，揭示了掺杂/复合/孔径调节对氧电极电催化性能的协同增强机制，实现了系列性能可媲美甚至优于商品贵金属材料的碳基催化剂的研发，其各项指标参数均处于国际领先水平；深入探讨 了一体化碳膜电极的力学性能和电化学稳定性的关联，探索了高性能碳基电极材料的液态及固态电池应用，并发展了一种高性能、易加工、可回收的新型柔性水凝胶电解质，为推动高性能、低成本碳基电极材料及电池研发提供了必要的基础理论和关键技术。. 项目相关工作在国际期刊上共发表论文10篇，影响因子均大于3(影响因子大于10的5篇)；申请国家发明专利7项，授权4项，圆满完成本项目拟定的研究内容和目标(拟定目标：预计在国外学术期刊和国际会议上发表SCI收录论文8篇以上，其中影响因子大于3的5篇以上；申请国家发明专利2项以上)。