The enhanced activity of dinuclear metallophthalocyanines amino-functionalized carbon nanotube-based oxygen reduction reaction catalysts

Abstract

Dinuclear metallophthalocyanines Fe2Pc2(CP)4 containing carboxyl substitutes were wrapped with amino-functionalized carbon nanotubes (MWCNTs-NH2) to enhance electrocatalytic activity for oxygen reduction reaction (ORR) using a facile “in situ” amidation reaction. The morphological characteristics and chemical environment of the Fe2Pc2(CP)4/MWCNTs-NH2 composites were characterized by scanning electron microscope (SEM), X-ray diffraction, Ultraviolet–visible (UV-Vis), Fourier Transform infrared (FTIR), and X-ray photoelectron spectroscopy. The electrocatalytic activity of ORR was tested and analyzed by cyclic voltammetry and linear sweep voltammetry. The results showed that the π–π interactions between the Fe2Pc2(CP)4 and MWCNTs-NH2 dramatically enhanced the π electron density in the conjugated structure, and oxygen could be reduced much more easily. Moreover, the oxygen reduction reactions mainly proceeded a one-step four electron process for Fe2Pc2(CP)4/MWCNTs-NH2 catalysts. The dispersion and electrocatalytic performance of M2Pc2Rn had be enhanced after being loaded on functionalized carbon nanotubes.