Catalysts for oxygen electroreduction based on multi-walled carbon nanotubes doped with cobalt, iron phthalocyanines, modified with palladium

Abstract

The influence of various dopants and modifiers on the catalytic activity of multi-walled carbon nanotube (MWCNT)-based oxygen reduction reaction catalysts was investigated. Transition metal phthalocyanines and urea were employed as nitrogen sources. Raman spectroscopy revealed that the incorporation of metal phthalocyanines leads to the formation of new carbon layers and a significant decrease in the overall ordering of the materials. All synthesized catalysts exhibited a mesoporous structure. Powder X-ray diffraction analysis elucidated the phase composition of the synthesized materials. The electrochemical performance was assessed using linear and cyclic voltammetry in a three-electrode cell with a rotating disk electrode. Notably, the MWCNT_CoPc_FePc_Pd catalyst demonstrated the highest activity and stability, approaching the performance of a commercial platinum catalyst in all electrochemical metrics. Furthermore, the MWCNT_CoPc_FePc_Pd catalyst, when tested in a fuel cell, exhibited high efficiency and stability comparable to those of a commercial platinum catalyst.