Distinct influence of Cd in the electrocatalyst of Ni-Co-Cd/CNFs nanoparticles as a catalyst in direct alcohol fuel cells (DAFCs)

Abstract

Different percentages of less expensive metal alloy-decorated nanofiber catalysts have been successfully manufactured using the electrospinning method to replace platinum in direct alcohol fuel cells (DAFC). The synthesis and characterization of catalysts, namely Ni-Co-Cd/CNFs, with a metal fixed ratio of 20 % wt. for DAFC applications are the main goals of this work. Two different catalyst concentrations were prepared with fixed nickel concentrations (Ni₁₂Co₆Cd₂ & Ni₁₂Co₄Cd₄). This research represents the first preparation of ternary Ni-Co-Cd/CNF for DAFC applications. Various methods, including electrochemical tests, transmission electron microscopy, scanning electron microscopy, and x-ray diffraction, are used to characterize the catalysts. Scanning electron microscopy (SEM) revealed that the fabricated sample exhibited a good nanofiber form and a distinct nanoparticle look. The samples' capacity for alcohol electrocatalysis was assessed using cyclic voltammetry, impedance spectroscopy, chronoamperometry, scan rate, and response time. The oxidation peak current density and electrode stability both rise when the concentration of Cd in Ni-Co-Cd/CNF increases. The oxidation peak current density of Ni₁₂Co₄Cd₄ at the optimum ethanol concentration (1 M ethanol in 1 M KOH) is found to be 29.7 mA/cm². While the maximum current density is found to equal 38.86 mA/cm². In addition, the CV results yield the oxidation peak current density to be 3.5 mA/cm² at the optimum methanol concentration (1 M methanol in 1 M KOH). Ni₁₂Co₄Cd₄ exhibits promoted electrochemical properties to ethanol electrooxidation rather than methanol oxidation. Furthermore, these findings are enhanced by the highly calculated diffusion coefficient of Ni₁₂Co₄Cd₄ towards ethanol in comparison with methanol (2.30 × 10⁻⁶ cm²/s for ethanol and 3.07 × 10⁻⁷ cm²/s for methanol). This work has demonstrated how to use a unique technique to develop an efficient alcohol electrooxidation catalyst based on nickel, cobalt, and cadmium nanoparticles.