石墨炔纳米带非金属元素掺杂可控改性及其氧还原催化性能研究

With the growing energy demand and the depletion of fossil fuels, increasing efforts have been devoted to develop the low-priced but efficient non-metal oxygen reduction reaction (ORR) catalysts as cathode to flourish fuel cells industry. Based on the two dimensional graphdiyne that has been experimentally synthesized, this project intends to build various of graphdiyne nanoribbons (GDYNR) via non-metal doping. By using the density functional theory, the nature of doping element and site will be revealed and the interaction between GDYNR and reactants or intermediates will be investigated. The whole dynamic process of ORR will be simulated under acid environment to determine the reaction mechanism and rate determining step, the competitive relationships among active sites will be analyzed to build a model of fast screening GDYNR catalysts with high activity, the correlation between electronic structure of active site and catalytical activity will be consider to build the structure-function relationship. This project is aimed to design several low-priced non-metal GDYNR catalysts with high ORR activity via single- or co-doping. The implemention of present project will provide new strategy to design and develop highly active non-metallic catalysts with low price, and will enrich and improve the research of graphyne material systems.

开发高效且廉价的非金属氧还原催化剂是当前燃料电池阴极催化技术领域的研究热点。本项目拟以实验中已合成的石墨二炔为基体构建新型纳米带结构，利用非金属元素掺杂作为修饰手段，通过密度泛函理论计算，系统研究非掺杂对石墨二炔纳米带性质和化学吸附的影响。在酸性条件下探究各活性位的活性和催化机理，剖析各活性位之间的竞争关系，探索快速筛选高活性催化剂的方法。建立活性位电子结构和催化活性间的构效关系，阐明其宏观机理与微观过程之间的内在联系，并进一步设计出多种具有高活性高稳定性的非金属掺杂石墨二炔纳米带氧还原催化剂。本项目的开展将为高活性非金属催化剂的设计开发提供新的途径和思路，丰富和完善石墨炔材料体系的研究。

本项目通过密度泛函理论计算系统研究了石墨炔材料在电催化和储锂等方面的应用。设计了多种N原子单掺及共掺石墨炔薄膜，揭示sp-N和sp2-N掺杂的协同作用是N掺杂石墨炔高活性的来源。但是当剪切成一维纳米带时，只有sp2-N掺杂能有效地提高各类纳米带的的ORR和HER催化活性，随着sp2-N的位置从带边移动到中心的变化，并且效率随掺杂位置深入逐渐降低，机器学习结果证实活性位点周围的环境对催化活性的影响至关重要。随后，将多种石墨炔纳米管应用于ORR和HER催化方面，发现了多个具有高活性、多活性位点的纳米管，同时发现ΔGOOH和ΔEH之间存在线性关系，由此提出EH作为对HER和ORR双功能电催化剂理性设计的通用描述符。设计了多种B原子共掺石墨炔薄膜高效催化NRR，限制电压低至-0.12 V, 并提出了一个新的催化活性通用描述符用。随后，将纳米管应用到储锂领域，发现显示大曲率可以暴露p电子有利于Li的吸附，而且为Li的扩散提供了良好的通道。总之，本项目设计出了多种面向ORR、HER、NRR等方向的高活性高稳定性的石墨炔催化剂，确定了各活性位点种类和催化机理，阐明其宏观机理与微观过程之间的内在联系，建立活性位电子结构和催化活性间的构效关系，提出了新的快速预测催化活性的描述符，为高活性非金属催化剂的设计开发提供新的途径和思路。本项目的开展极大地了丰富和完善石墨炔材料体系的研究。相关研究成果发表在Chem. Eng. J等期刊上9篇。