基于嵌段共聚物的氮掺杂有序多孔炭结构调控及其对氧气还原反应催化机制的影响规律

In this study, highly functionalized ordered porous carbon is obtained from template method through synthesizing block-co-polymer which could applied as both the template and precursor. Based on the phase-separation theory, the BET surface area and pore structures could be controlled by tailoring the composition of the template-precursor, and the relationships between the structures of template-precursor, conditions during the carbonization and the pore structures of the products are also investigated. Through the design of template-precursor by compounding the nitrogen contained precursors, such as amino acid and collagen by grafting or blending, the controlling of porosity and surface doping with nitrogen atoms are both achieved during the carbonization process of ordered porous carbon owing to the high energy transition. The obtained nitrogen-doped ordered porous carbon is applied as the electrocatalyst for the oxygen reduction reaction (ORR). The catalytic properties are further studied, focused on the effects of specific surface area, pore structure and surface doping on the improved catalytic activity, stability and mechanisms towards the ORR, which provides potential approach for the design and functionlization of novel ORR electrocatalysts.

本研究针对模板法控制精度有限，过程复杂等问题，将成炭模板及前驱体复合为嵌段共聚物并炭化制备有序多孔炭。以嵌段共聚物微观相分离理论为指导，着重研究前驱体组成、微观形态对产物孔道结构特征的影响，系统分析炭化过程中各因素的作用规律，探索精确控制有序多孔炭结构的最优条件，实现对其比表面积及孔道形貌、分布的有效调控。从分子层面对前驱体-模板进行结构、组成设计，通过氨基酸小分子接枝及天然高分子共混的方法，利用成炭过程中高能量化学变化，对有序多孔炭表面进行氮元素的掺杂，建立在炭化反应中实现高比表面积，立体孔道分布，表面功能化等特性整合优化的可靠途径。将表面氮掺杂有序多孔炭材料应用于氧气还原反应的催化剂，通过系统的电催化性能研究，阐明氮掺杂有序多孔炭材料比表面积，有序度，孔隙结构对催化活性及机理的促进机制，明确表面原子掺杂对催化性能改善及稳定性提高的作用机理，为实现新型电催化材料的设计及功能化奠定基础。

本研究以嵌段聚合物为成炭模板炭化制备有序多孔炭，着重研究前驱体组成、微观形态对产物孔道结构特征的影响，系统分析炭化过程中各因素的作用规律，探索精确控制有序多孔炭结构的最优条件，实现对其比表面积及孔道形貌、分布的有效调控。以嵌段共聚物PEO-PPO-PEO为模板，酚醛树脂为前驱体，制得二维六方通孔介孔结构的有序介孔炭，通过调整炭化温度、升温速率等条件，实现了对产物比表面积、孔道结构的有效调控，阐明模板—前驱体热固化及炭化机理。以硼酸、三氯化铁、喹啉等掺杂物与前驱体混合，在保留有序孔道结构的前提下，对所得多孔炭材料进行多种元素的原位掺杂。通过调整前驱体比例、炭化温度，采用酸洗、酸化等后处理方法对产物形貌、成分、结构进行调控。考察具有不同形貌、结构的有序多孔炭的电容特性及氧气还原反应催化性能，研究产物结构、成分特性对其电化学性能的的影响规律，阐明杂原子掺杂对于炭材料表面活性及稳定性的作用机制。