碳纳米管阵列负载的单原子位点催化剂的设计合成及电催化氧还原性能研究

The development of non-noble metal based electrocatalysts to substitute expensive Pt-based catalysts is of great significance for oxygen reduction reaction, which is an important cathode reaction in fuel cells. Carbon-supported non-noble metal single-atomic-site catalysts have been found to be efficient in oxygen reduction reactions. However, the current research mainly focuses on powder catalysts, and some problems such as poor mass and electron transport as well as poor stability remain unsolved. This project aims to combine single-atomic-site catalysts and nanoarrays together. Firstly, ZnO nanoarrays grown on carbon paper will be used as the template, and through introducing target metal precursors (MP: Fe, Co, Cu, Mn nitrate salts or acetylacetonates) while the conversion of ZnO to ZIF, ZnO@(MP@ZIF) will be formed, which will become metal single-atomic-site catalysts anchored on carbon nanotube arrays after carbonization and acid leaching processes. The synthetic conditions will be optimized according to the oxygen reduction reaction performance. Then, the catalytic activity and stability will be adjusted through doping atoms in the carbon support. Finally, we will combine the X-ray absorption characterization and theoretical calculations to study the oxygen reduction mechanism and reveal the relationship between the structure and properties of the single-atomic-site catalysts. This project will provide insight into the development of single-atomic-site catalysts and high-performance fuel cells.

氧还原反应是燃料电池中重要的阴极反应，开发取代高成本铂基的氧还原电催化剂具有重要意义。碳负载的非贵金属单原子位点催化剂被广泛应用于氧还原反应，然而目前的研究主要集中于粉末型催化剂，仍存在物质和电子传输能力差、稳定性不高等问题。本项目拟将金属单原子位点催化剂与纳米阵列结合在一起，设计新型自支撑电催化剂。首先，以碳纸上生长的ZnO纳米阵列为模板，将ZnO原位转化为ZIF的同时引入目标金属前驱体（MP：Fe、Co、Cu、Mn的硝酸盐或乙酰丙酮配合物）形成ZnO@(MP@ZIF)纳米阵列，经高温碳化、酸洗，合成碳纳米管阵列负载的金属单原子位点催化材料，通过氧还原性能测试反馈优化合成条件。然后，通过杂化修饰，调控材料的催化活性和稳定性。最后，结合X射线吸收谱和理论计算，探究氧还原反应机理，揭示单原子位点催化剂与氧还原性能的构效关系。本项目将为高性能燃料电池的发展提供新的思路。

开发新型高效的氧还原电催化剂取代铂基催化剂，降低燃料电池等新能源器件成本，具有重要的科学意义和实际价值。本项目通过对单原子位点催化剂的结构设计调控，构筑了在氧还原反应中具有优异性能的催化剂，系统探究了构效关系，并组装了具有优异性能的锌-空气燃料电池。项目的实施取得了系列重要进展：（1）发展出了自模板法、原位煅烧法等碳纳米管阵列负载单原子位点催化剂的合成策略，实现了碳纳米管阵列负载单原子位点催化剂的可控合成；（2）构筑了在碱性介质和锌-空气燃料电池中具有优异性能的Mn单原子位点催化剂，并利用原位X射线吸收谱结合理论计算，阐释了其构效关系；（3）拓展了单原子位点催化剂和纳米阵列等材料的可控合成方法，得到了系列性能优异的新型功能材料。在本项目的资助下，发表论文12篇，申请发明专利3项，培养硕士研究生2名。项目的研究成果为单原子位点催化剂的理性设计提供了简单、可控的方法，同时也为新能源器件的实际应用提供了具有潜力的催化剂。