Fe-N-C类氧还原催化剂活性来源的探究及高性能催化剂的构筑

Highly active Fe-N-C electrocatalysts are promising candidates for replacing the expensive state-of-the-art Pt-based electrocatalysts for oxygen reduction reaction (ORR). Understanding the activity origin and thus precisely constructing the highest active sites in Fe-N-C electrocatalysts are necessary and crucial for their applications. This proposal will focus on unraveling the origin of the high ORR activity of Fe-N-C electrocatalysts by means of designing model catalysts individually containing each potential active site and their combinations and investigating their ORR behavior to reveal the role of each active site and their synergetic effects on ORR with the help of the delicately designed control catalysts and experiments. ECSTM technique will be used to in-situ image the single oxygen adsorption-desorption process and reduction reaction of on the selected active site at molecular scale. Together with the theoretical calculations on the oxygen adsorption-desorption on active sites, the proposal will be able to discover the catalytic sites with the highest ORR activity. After the further modulation on the microenvironment and their electronic structures, the highly active catalytic sites with superior stability are expected to be explored and guide the synthesis of high-performance Fe-N-C electrocatalysts for the diverse applications like fuel cells by enriching these sites and make them accessible to the electrolyte.

高活性Fe-N-C类氧还原催化剂有望替代传统昂贵的铂基金属催化剂。其催化活性来源不甚明了、催化活性中心难以精确控制构筑，导致性能有待提升是限制其应用的关键科学问题。本项目拟从分解设计并构筑结构明确、成分清晰的模型催化剂出发，深入探究Fe-N-C催化剂中各类催化位点的氧还原活性及其相互之间的协同作用；利用电化学扫描隧道显微技术，在分子尺度上原位研究催化位点上氧的吸脱附过程与还原过程，结合理论计算，归属Fe-N-C催化剂中高氧还原活性中心，阐明催化剂中其它位点与成分对其性能的影响，以期揭示其氧还原活性来源；进而通过催化活性位点的微观结构调控与电子性质调控，进一步提升所述高活性催化位点的活性与稳定性，并反馈指导催化剂的设计；最后发展能提高所述高性能催化位点在催化剂中数量与密度的纳米结构化与可控合成技术，实现可控制备高活性、高稳定性的Fe-N-C类氧还原催化剂的研究目标，探索其在燃料电池中的应用。

Fe-N-C类氧还原催化剂有望替代传统铂基催化剂。项目针对其催化活性来源不甚明了、活性中心难以精确构筑和性能有待提升等关键科学问题，从设计并构筑结构明确的催化位点出发，探究了各类催化位点的氧还原活性及其相互协同作用；利用先进表征技术，在分子尺度上研究了催化位点上氧气的吸脱附过程与还原过程；结合理论计算，阐明了高活性中心，揭示了催化位点成分与结构对其性能的影响；进而通过催化活性位点的微观结构调控与电子性质调控，提升了所述高活性催化位点的活性与稳定性；发展了系列高密度金属氮碳类催化位点的可控构筑策略，获得了高性能催化剂与电催化能源器件。.发表学术论文39篇，申请中国发明专利6项，培养博士生5名和硕士生1名。