Carbon-based catalyst towards oxygen reduction reaction (ORR) has been investigated for years, one facile and typical strategy reported by a lot of literature to improve the ORR activity was the high-temperature annealing. Our group has previously studied the annealing process and confirmed the removal of oxygen-containing functional groups (OFGs) would bring benefits to ORR activity. However, the removal of which kind(s) of functional group will influence the ORR activity most has not been verified. In this work, a two-step oxidation method was applied by a weak oxidation treatment using H₂O₂ firstly and selectively adjusting the ratio of phenol and carbonyl/quinone. Then the ORR activity of the sample was carefully investigated by gradually removing specific OFGs with a rapid annealing process. The results suggested that the topological defects from the removal of phenol, carbonyl/quinone is the key to enhance the ORR activity of MWCNTs.

多年来已经研究了碳基催化剂用于氧还原反应（ORR），高温退火是许多文献报道的一种提高ORR活性的简便且典型的策略。我们的小组先前已经研究了退火过程，并确认去除含氧官能团（OFG）将为ORR活性带来好处。然而，尚未证实去除哪种官能团将最影响ORR活性。在这项工作中，通过使用H ₂ O ₂的弱氧化处理，采用了两步氧化方法首先有选择地调节苯酚与羰基/醌的比例。然后，通过快速退火过程逐渐去除特定的OFG，仔细研究了样品的ORR活性。结果表明，去除苯酚，羰基/醌的拓扑缺陷是增强MWCNTs ORR活性的关键。