Influence of Nitrogen doping on the Catalytic Activity of Ni-incorporated Carbon Nanofibers for Alkaline Direct Methanol Fuel Cells

In this study, the influence of nitrogen doping on the electrocatalytic activity of carbon nanofibers incorporated with nickel nanoparticles toward methanol oxidation is introduced. The modified carbon nanofibers have been synthesized from calcination of electrospun nanofiber mats composed of nickel acetate tetrahydrate, poly(vinyl alcohol) and urea in argon atmosphere at 750 °C. The utilized physicochemical characterizations indicated that the proposed strategy leads to form carbon nanofibers having nickel nanoparticles and doped by nitrogen. Formation of pure nickel can be attributed to the abnormal decomposition of the acetate anion which leads to form strong reducing gases (CO and H2), the formed nickel catalyzes graphitization of the utilized polymer to form carbon nanofibers. Investigation of the electrocatalytic activity indicated that nitrogen doping strongly enhances the oxidation process of methanol as the current density increases from 52.5 to 198.5 mA/cm2 when the urea content in the original electrospun solution was 4 wt% urea. Moreover, the nanofibrous morphology exhibits distinct impact on the electrocatalytic activity. Also, nitrogen-doping enhanced the stability of the introduced Ni-based electrocatalyst.