In-situ synthesis of Ni/N-doped CNFs-supported graphite disk as effective immobilized catalyst for methanol electrooxidation

•Ni/N-CNFs-attached graphite disk are introduced as promised immobilization strategy.•The proposed immobilization has increased the current density more than three folds.•N-doping shows distinct role in enhancement the electrooxidation of methanol.•The introduced Ni/N-CNFs-graphite disk displays good stability in alkaline medium.

In this study, a facile, controllable, and efficient process (electrospinning followed by calcination at 1100 °C under argon atmosphere) is developed for in-situ synthesis of Ni/N-CNFs catalyst as thin film immobilized on graphite disk. Moreover, the influence of nitrogen content on the catalytic activity of the supported Ni-doped CNFs toward methanol oxidation was investigated. The composition and morphology of the prepared catalysts were characterized by XRD, EDX, FE-SEM and TEM techniques. The electrocatalytic activity and stability were evaluated by cyclic voltammetry (CV) and chronoamperometry, respectively. Compared to the powder form, the results indicated that the proposed in-situ immobilization of the introduced nanofibers on graphite disk reveals distinct enhancement in the electrocatalytic activity due to merging of the underneath nanofibers with the graphite support which eliminates the interfacial resistance. Numerically, the detected maximum current density was 270.44 and 80.59 mA/cm2 for Ni/N-CNFs/graphite and unsupported nanofibers, respectively. Moreover, the obtained results have also showed that nitrogen doping effectively enhances the electrocatalytic activity and stability of Ni/CNFs toward methanol oxidation in the alkaline medium. However, due to the influence of methanol content on the water-alcohol mixture fluidity, the optimum methanol concentration was observed to be 0.5 and 5.0 M for the supported and unsupported nanofibers, respectively. Overall, this study opens new avenue to prepare one-pot current collector/electrode plate to be utilized in the fuel cell technology.