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Study on the Effects of a π Electron Conjugated Structure in Binuclear Metallophthalocyanines Graphene-Based Oxygen Reduction Reaction Catalysts
oleh: Gai Zhang, Bulei Liu, Yufan Zhang, Tiantian Li, Weixing Chen, Weifeng Zhao
Format: | Article |
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Diterbitkan: | MDPI AG 2020-05-01 |
Deskripsi
The high overpotentials for oxygen reduction reaction (ORR) create an extremely negative impact on the energy efficiency of the air-based battery systems. To overcome this problem, binuclear ball-type metallophthalocyanines containing methoxy substituents (M<sub>2</sub>Pc<sub>2</sub>(EP)<sub>4</sub>, M = Fe(II), Co(II) and Zn(II)) were wrapped with polystyrene sodium sulfonate (PSS) modified graphene oxide (GO), using a facilely “solvothermal π-π assembly” method to prepare M<sub>2</sub>Pc<sub>2</sub>(EP)<sub>4</sub>/PSS-Gr composites. Compared with the commercial Pt/C catalysts, the M<sub>2</sub>Pc<sub>2</sub>(EP)<sub>4</sub>/PSS-Gr composites enhanced the catalytic activity of oxygen reduction reaction. The π electron conjugated structure of the MN<sub>4</sub>-type phthalocyanine macrocyclic system strongly influenced the one-step four-electron electrocatalytic process of the M<sub>2</sub>Pc<sub>2</sub>(EP)<sub>4</sub>/PSS-Gr composites. Moreover, the π-π interactions between the M<sub>2</sub>Pc<sub>2</sub>(EP)<sub>4</sub> and PSS-Gr dramatically enhanced the π electron density in the conjugated structure and oxygen could be reduced more easily. The electrocatalytic activity test was displayed in the order of Fe<sub>2</sub>Pc<sub>2</sub>(FP)<sub>4</sub>/PSS-Gr > Co<sub>2</sub>Pc<sub>2</sub>(EP)<sub>4</sub>/PSS-Gr > Zn<sub>2</sub>Pc<sub>2</sub>(EP)<sub>4</sub>/PSS-Gr. The results indicated that the catalytic performance of M<sub>2</sub>Pc<sub>2</sub>R<sub>n</sub> could be enhanced by the modification of π electron conjugated structure of M<sub>2</sub>Pc<sub>2</sub>(EP)<sub>4</sub> and carbon materials.