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准确理解金属大环配合物(如N4-Fe2+)体系的氧化还原化学性能,对氧还原反应(ORR)电催化剂的基础研究和合理设计具有重要意义.本文采用微波法将三种不同酞菁铁类金属大环配合物吸附在碳纳米管上,分别记为(NH2)4FePc@CNTs,(t-Bu)4FePc@CNTs和FePc@CNTs,考察了取代基对Fe3+/Fe2+氧化还原电位的影响,以及碱性介质中的氧还原反应催化活性.结果表明,FePc@CNTs,(t-Bu)4FePc@CNTs和(NH2)4FePc@CNTs的ORR起始电位分别为0.98,0.96和0.96 V,而半波电位(E1/2)由高到低的顺序为FePc@CNTs(E1/2=0.91 V),(t-Bu)4FePc@CNTs(E1/2=0.87 V),(NH2)4FePc@CNTs(E1/2=0.83 V).与20％Pt/C(E1/2=0.85 V)相比,FePc@CNTsFePc@CNTs具有优异的ORR性能.在活性、稳定性和耐甲醇性方面,FePc@CNTs复合材料比其他复合材料表现出更高的ORR性能.研究发现,FePc上的供电子基团可以显著改变N4-Fe2+活性位点的电子云密度,增加dz2轨道(HOMO)的能量,并观察到Fe2+/Fe3+氧化还原电位显著向阴极方向移动.结果表明,取代基的高电子贡献能力降低了HOMO和LUMO(O2的杂轨道*-轨道)之间的电子耦合,从而降低了氧还原催化活性.因此,FePc框架外围的供电子基团对ORR不利.本文阐明了取代基电子效应-金属大环配合物氧化还原电位与ORR催化性能之间的关系,为ORR催化剂活性中心的构建和调控提供了借鉴.“,”A precise understanding of the redox chemistry of Nm-Mn+ (like N4-Fe2+) systems is essential for fundamental studies and rational design of Nm-Mn+-based electrocatalysts for the oxygen reduction reaction (ORR). Herein, three different iron phthalocyanines (FePcs) adsorbed on carbon nanotubes ((NH2)4FePc@CNTs, (t-Bu)4FePc@CNTs, and FePc@CNTs) were evaluated to demonstrate the effect of the electron donating power of the substituents on the Fe3+/Fe2+ redox potential of FePc@CNTs and the role of these composites as ORR mediators in alkaline media. The Fe3+/Fe2+ redox potential of the FePcs was found to shift towards the cathodic region upon substitution with elec-tron-donating groups. This up-field shift in the eg-orbital leads to a lower overlap between the onset potential of the Fe3+/Fe2+ redox couple and that of the ORR, and thus, the ORR activity decreased in the following order based on the substitution of FePc: -H > -t-Bu > -NH2.