Carbon nanofibers doped by NixCo1−x alloy nanoparticles as effective and stable non precious electrocatalyst for methanol oxidation in alkaline media

Abstract

Bimetallic alloys have superior physiochemical characteristics compared to the individual metals. In this study, NixCo1−x (x=0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) alloy nanoparticles incorporated in carbon nanofibers are investigated as electrocatalysts for methanol oxidation in the alkaline media. Preparation of the introduced nanofibers is achieved by calcination of electrospun nanofibers composed of nickel acetate, cobalt acetate and poly(vinyl alcohol) in argon atmosphere. The catalytic activity of cobalt enhances the carbonization of the utilized polymer which results in producing nickel/cobalt alloys nanoparticles embedded in carbon nanofibers. Due to the synergistic influence of the introduced alloy, both of the current density and onset potential were distinctly affected by the nanoparticles composition; Ni0.5Co0.5 alloy nanoparticles-doped carbon nanofibers reveal current density and onset potential of 240mA/cm2 and 110mV [vs. Ag/AgCl], respectively. Interestingly it was proofed that, compared to nanoparticles, the nanofibrous morphology has a distinct positive influence on the electrocatalytic activity due to the effect of the one dimensional structure which facilitates the electrons transfer and consequently decreases the IR drop. The introduced nanofibers showed good stability because of the alloy structure. Overall, this study opens new avenue for the transition metals alloys and the nanofibrous morphology to be invoked to produce novel and effective class of non-precious electrocatalysts.