Highly active non-precious metal catalyst based on poly(vinylpyrrolidone)–wrapped carbon nanotubes complexed with iron–cobalt metal ions for oxygen reduction reaction

Abstract

Multi-walled carbon nanotubes (MWCNTs) are functionalized with 2-pyrridone functional groups by wrapping poly(vinylpyrrolidone) polymers around it under high-powered sonication. The presence of 2-pyrridone functional groups facilitates the complexation of metal ions (Fe3+, Co2+). The best oxygen reduction catalyst, MWCNT–FeCo, is synthesized by annealing poly(vinylpyrrolidone)/MWCNTs/Fe–Co complex in ammonia at 900°C and exhibits nearly four-electron oxygen pathway (n ∼3.8). X-ray diffraction pattern shows that low loading of metallic Fe nanoparticles (0.79wt.%) and bimetallic FeCo nanoparticles (0.34wt.%) is formed on the MWCNT–FeCo catalysts. X-ray photoelectron spectroscopy reveals that ∼1at.% of nitrogen has been doped into MWCNT–FeCo catalysts.