Metallophthalocyanines (MPc, M=Fe or Co) have been investigated extensively as a typical type of transition metal macrocyclic catalysts for the oxygen reduction reaction (ORR). However, the understanding about ORR catalyzed by binuclear even heterodimetallic phthalocyanines in acidic condition is still not sufficient. Herein we synthesized two homodimetallicphthalocyanine (FePc‐PcFe and CoPc‐PcCo) and a heterodimetallic phthalocyanine (FePc‐PcCo). The electrocatalytic activity of as‐synthesized compounds were characterized by cyclic voltammetry (CV) and rotating disk electrode (RDE). Generally, the binuclear metallophthalocyanines show higher activity than their monomeric analogues including FePc and CoPc. Also, the Fe compounds exhibit better catalytic performance than the Co phthalocyanines. However, interestingly the heterodimetallic phthalocyanine FePc‐PcCo shows similar half‐wave potential and ORR activity with FePc‐PcFe, rather than CoPc‐PcCo. This may be explained by XPS and XAS, which reveal a similar square‐planar structure existed in FePc‐PcCo and FePc‐PcFe and a non‐planar structure in CoPc‐PcCo. Furthermore, the increasing of the ORR activity among those five catalysts is well in agreement with the descending LUMO energies in DFT calculations. A lower LUMO energy indicates a favorable adsorption of O₂, which in turn affects the ORR performance.

中文翻译：

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均相和杂双金属酞菁在酸性介质中用于氧还原反应的电化学和光谱研究

金属酞菁（MPc，M = Fe或Co）已被广泛研究作为氧还原反应（ORR）的典型过渡金属大环催化剂。然而，对双核甚至异双金属酞菁在酸性条件下催化的ORR的了解仍然不够。在这里，我们合成了两个均二金属酞菁（FePc-PcFe和CoPc-PcCo）和一个异二金属酞菁（FePc-PcCo）。通过循环伏安法（CV）和旋转圆盘电极（RDE）表征了所合成化合物的电催化活性。通常，双核金属酞菁显示出比其单体类似物（包括FePc和CoPc）更高的活性。而且，Fe化合物显示出比Co酞菁更好的催化性能。然而，有趣的是，异双金属酞菁FePc-PcCo与FePc-PcFe相比，与CoPc-PcCo表现出相似的半波电势和ORR活性。XPS和XAS可能解释了这一点，它们揭示了FePc-PcCo和FePc-PcFe中存在类似的正方形平面结构，而CoPc-PcCo中存在非平面结构。此外，这五种催化剂中ORR活性的增加与DFT计算中LUMO能量的下降完全吻合。较低的LUMO能量表明O的有利吸附 在DFT计算中，这五种催化剂中ORR活性的增加与LUMO能量的下降完全吻合。较低的LUMO能量表明O的有利吸附 在DFT计算中，这五种催化剂中ORR活性的增加与LUMO能量的下降完全吻合。较低的LUMO能量表明O的有利吸附₂，这反过来会影响ORR性能。