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

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 pi-pi interactions between the Fe2Pc2(CP)(4) and MWCNTs-NH2 dramatically enhanced the pi 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.