生物质衍生掺杂碳基催化剂的制备/改性及其机理研究

Doped carbon catalyst is recognized as a type of most promising catalyst for fuel cell application, because its application will led to the sharp decrease of the usage of precious metal catalysts, thus resulting in the greatly decrease of the cost of fuel cells, and promoting the progress of the commercialization of fuel cells. However, there are still some serious problems existed for doped carbon catalyst, such as, poor fuel cell performance, unclear in the active center structure and its formation mechanism, lack of the direction of theory for the doping of heteroelements, therefore, it is urgent and necessary to pursuit the investigation to deep extent. Biomass materials is a kind of materials with some important advantages, such as with a great variety, with various structure and morphology, rich in heteroelements, etc, it should be the perfect precursor candidate for the preparation of doped carbon catalysts. In this project, we will attempt to prepared a novel and high performance doped carbon catalysts derived from biomass materials based on the previous works, will explore the new preparation technologies, and investigate the effects of the composition, structure and morphology of biomass precursors, as well as the promotion and modification, on the structure and the performances of the biomass derived doped carbon catalysts. Through the characterization of the biomass derived catalysts with XPS, TEM, and Raman etc, we will try to reveal the existing status of heteroelements in the catalysts, and the interaction of heteroelements with carbon atoms, reveal the structure of the active centers and its formation mechanism, as well as the mechanism of oxygen reduction on the doped carbon catalysts. Furthermore, we will try to reveal the reasons why the single cell performance of doped carbon catalyst is much poorer than their performance in CV measurements. The results of this project will provide scientific bases and theoretical support for the investigation of doped carbon catalysts and their practical applications in fuel cells.

掺杂碳基催化剂可以大幅度降低燃料电池中贵金属铂的用量，对于降低燃料电池成本和促进其商业化进程具有十分重要的意义。目前的掺杂碳基催化剂存在电池活性不高、活性中心结构及形成机理不清、掺杂带有尝试色彩等问题，亟待开展深入的探索和研究。生物质材料具有种类繁多、结构和形态各异、富含各类原子分子水平上的杂元素等重要优点，是制备高性能掺杂碳催化剂的理想的前驱体材料。本工作拟在已有工作基础上，探索采用生物质材料为前驱体制备掺杂碳基催化剂，探索新的制备技术，研究生物质组成、结构、形貌以及进一步掺杂及改性对于催化剂性能的影响及其规律。通过采用XPS、TEM、拉曼光谱等技术对催化剂的表征，揭示掺杂元素的存在形态及其与碳之间的相互作用，揭示催化剂的活性中心结构及其形成机理，以及氧在碳基催化剂表面的还原机理。揭示碳基催化剂单电池性能不良的本质原因并找出解决方法，为碳催化剂的研究及实际应用提供重要科学基础及理论支撑。

随着燃料电池汽车大规模商业化在我国的展开，探索和研究高效低铂及非铂催化剂，有效降低燃料电池的成本，已成为该领域的十分迫切的研究课题。掺杂碳基阴极催化剂具有完全无需使用昂贵的金属铂和成本低廉的重要优点，是一类最具吸引力、国际上研究投入最高的燃料电池非铂催化剂。选择合适前驱体和制备技术研究制备具有特殊结构和形貌的掺杂碳基催化剂一直是该领域的重要研究课题。.申请人在国际上率先提出利用生物质来制备高性能掺杂碳基催化剂的研究思路，并率先开展了相关研究工作；在本项目资助下，研究工作的主要内容包括：.1.探索了使用各种不同类型的生物质来制备高性能掺杂碳基催化剂的可能性；.2.探索了从生物质出发制备掺杂碳基催化剂的新技术和新方法；.3.针对目前的碳基催化剂在酸性条件下活性不足的问题，提出了增强碳基催化剂活性的有效方法；.4.研究了碳基催化剂中各掺杂元素的存在状态、相互作用及其机理；.5.研究了生物质衍生碳基催化剂在质子交换膜燃料电池、锂空气电池、以及超级电容器中的催化作用；.6.在本项目资助下，探索了其它新型前驱体制备高性能碳基催化剂的可能性。..本项目的重要研究结果包括：.1.证实了富含N,S,P等元素的生物质可以成为制备掺杂碳催化剂的优质前驱体材料，制得的催化剂的性能可完全媲美（或者超过）通过复杂的化学合成制得的前驱体所制得的掺杂碳催化剂材料；.2.采用“水热分解-热裂解”二步法工艺，可以使得生物质制备的催化剂很好地保持生物质的形貌，具有很高的比表面积；本项目还提出了活化剂（氯化锌等）活化生物质制备碳催化剂技术，增强剂增强催化剂的活性及稳定性的技术，均可有效提升催化剂的性能；.3.发现生物质衍生的碳催化剂不仅具有很好的ORR（氧还原）催化性能，而且具有很好的OER性能；不仅可以用于燃料电池，还可以用作金属空气电池；.4.开展了以MOFs为前驱体的研究工作，取得了重要进展；.5.项目共发表SCI论文50余篇(标注)，在各类会议做邀请报告10多次；申请专利10余件。