Fabrication of bimetallic Ni‐Ag/CNFs nanoparticles as a catalyst in direct alcohol fuel cells (DAFCs)

Abstract

AbstractIn the present work, an attempt to improve DAFC by replacing platinum with cheaper materials. Ni acetate‐Ag nitrate supported by carbon nanofibers with three different samples (S1 95–5, S2 90–10, and S3 80–20%) for Ni and Ag, respectively, were synthesized by using the electrospinning method and then calcined under an Argon atmosphere at 900°C. Numerous analysis methods were employed to examine the chemical structure, the morphology, and the electrochemical (EC) features. The scanning electron microscope (SEM) confirms that all samples with different Ag concentrations exhibit good nanofiber morphology and a clear appearance of the nanoparticles. According to energy dispersive X‐ray (EDX) mapping, the results prove that the carbonized polyvinyl alcohol nanofibers (PVANFs) have a consistent and even distribution of nickel and silver with an accurate percentage as previously prepared by molar ratio. Transmission electron microscope (TEM) shows that the interior structure has an amorphous carbon nanofiber structure with embedded crystalline spheres of silver and nickel. From X‐ray diffraction (XRD) analysis, no hydroxide or oxide phases can be identified in the XRD pattern, which prove the existence of Ni‐Ag nanoparticles in the metallic phase. For the electrooxidation of ethanol and methanol, the samples' electrocatalytic characteristics were examined. The effects of the electrolyte concentration, scan rate on the catalytic performance and electrode stability were studied using cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance measurements (EIS). CV, chronoamperometry, and EIS reveal that the S2 sample has the best, superior electro‐oxidation activity for both methanol and ethanol with the highest current density. Hence, This research provided a promising approach to fabricating a promising bimetallic Ni‐Ag/CNFs catalyst to replace platinum in direct DAFCs.