Excellent catalytic activity of NiPd/C nanocatalysts for anodic oxidation of methanol in alkaline media

Abstract In this study, nanocatalyst NiPd was synthesized via a successful two-stage reduction process with NaBH4 and PVP. More specifically, the first stage involves NaBH4 reduction of Ni2+ ion to metallic Ni. Afterwards, Pd would be coated on the surface of the aformentioned Ni particles by reducing Pd2+ using the remaining NaBH4. The effect of experimental parameters on the synthesis and catalytic activity of the nanocatalysts, such as reaction temperature (30, 40, 50, 60, 70 °C), reaction time (60, 90, 120, 150, 180 minutes), Pd:Ni mole ratio (1:10, 3:10, 5:10, 7:10, 9:10). were investigated by X-ray diffraction (XRD), Energy dispersive spectroscopy (EDX), and transmission electron microscopy (TEM) were used to analyse the surface structure, composition and morphology of the catalyst samples. The catalytic activity and stability of the resulting NiPd/C catalysts were investigated towards the methanol oxidation reaction (MOR) in alkaline environment by cyclic voltammetry (CV) and chronoamperometry (CA) techniques. The results showed that the highest catalytic activity was found for the sample synthesized at 50 °C with 120-minute reaction time and the Pd:Ni molar ratio of 5:10. The influence of KOH and methanol concentrations on the catalytic activity of NiPd/C for methanol oxidation reaction in alkaline medium was also investigated. The results demonstrated the promising potential of NiPd/C nanomaterials as catalyst materials for the anodic layer in direct methanol fuel cells (DMFCs).