高掺杂度杂原子掺杂石墨烯的可控制备及其电催化氧还原反应性能研究

Oxygen reduction reaction (ORR) is a key process of fuel cells. The commercial electrocatalysts for ORR are Pt-based electrocatalysts, which suffer from poisoning, poor stability, high cost and limited resources. Therefore, it's in high demand to develop Pt-free or even metal-free electrocatalysts with good activity. Doped carbon with heteroatoms was well-developed as metal-free electrocatalyst for ORR, however, doping level is low, especially for those heteroatoms with highly different atomic size. High doping level is critically important to investigate the doping and catalysis mechanisms, and to improve the performance of catalysts. In this proposal, we will use plasma-enhanced thermal annealing method to preapre doped graphene with high doping level in a controlalble fasion as metal-free electrocatalysts for ORR. Plasma state of could signicantly enhance the reactivity of dopants and produce more doping sites by etching graphene, thus resultsing in highly doped grpahene. Combining with quantum chemistry calculation,the doping and catalysis mechanism would be studied. Based on the understantding on these fundamental issues, novel techniques are expected to be developed to prepare metal-free electrocatalysts for ORR.

氧还原反应（ORR）是燃料电池中的一个核心过程。目前商业上的ORR催化剂是铂基催化剂，但其易被毒化、稳定性差、价格昂贵且储量有限。因此，开发非铂、非金属的高性能ORR催化剂对降低电池成本、提高电池寿命至关重要。杂原子掺杂碳材料用作ORR催化剂被广泛报道，但掺杂度普遍较低，尤其是与碳原子尺寸差别较大的杂原子。高的掺杂度对研究掺杂和催化机理十分关键，也有助于开发高性能的非金属催化剂。本项目将利用等离子体增强热处理法实现高掺杂度石墨烯的可控制备，并研究其催化ORR性能。等离子体态可大大增强掺杂过程中各物种的反应活性，其刻蚀功能可有效产生掺杂位点，进而实现高掺杂度石墨烯的制备。在此基础上，结合实验和量化计算系统研究相关掺杂机制和催化机理，丰富电催化理论，并开发制备ORR非金属催化剂简便高效的新方法。

电催化反应发生在催化剂的表面，与催化剂表面电子结构密切相关。缺陷直接影响催化剂电子结构，影响反应物、中间体和产物的吸脱附过程，从而能调控其催化活性及选择性。本项目聚焦电催化剂缺陷化学，通过催化剂表面缺陷的构筑，设计高性能电催化剂，认识缺陷产生机制，理解缺陷与催化性能之间的构效关系，构建其在催化剂设计方面的应用基础，为新型催化剂的设计提供理论依据。通过自主搭建微区电化学平台，明确边缘缺陷碳的高活性，建立了碳本征缺陷-催化活性-表面电荷之间的构效关系。实现缺陷的选择性构筑，解析了其电催化机制。通过缺陷位的功能化修饰，赋予了催化剂新的功能。基于上述研究结果，发表SCI论文70余篇，34篇ESI高被引论文。1篇入选中国百篇最具影响力国际学术论文；缺陷电催化的研究理念也被各国科学家引用借鉴，对化学、材料等多学科产生重要影响，研究工作获得美国总统奖得主A.Gewirth教授等国内外权威专家高度评价。Nat. Nanotech.以全文亮点的方式报道和评价了项目完成人的工作。