Cost-effective non-noble metal supported on conducting polymer composite such as nickel nanoparticles/polypyrrole as efficient anode electrocatalyst for ethanol oxidation

Abstract

The adoption of fuel cells for portable electronic devices appears to be an efficient promising approach to alleviate the energetic dependence to fossil fuels. Poly-pyrrole (PPy) and nickel nanoparticles (NiNPs) based electro catalyst was synthesized by galvanostatic and potentiostatic modes respectively using the regeneration approach with the aim to accelerate the kinetics of anodic oxidation of ethanol with a low production cost, good catalytic activity, high resistance to poisoning species and long term stability. The electrochemical, morphological, structural, and catalytic features of the nanocomposite were investigated using several techniques such as cyclic voltammetry (CV), electrochemical Impedance spectroscopy (EIS), scanning electron spectroscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The effect of the NiNPs content on the electrocatalytic performance of NiNPs/PPy was investigated which lead to the optimized composition. An excessive amounts of nickel particles reduces the number of active sites of the material causing a sluggishness of the electron transfer path. Consequently, the optimal concentration of nickel which reveals the best electrocatalytic activity of NiNPs/PPy/CPE nanocomposite for ethanol electrooxidation is 6 mM. At this concentration, the value of the anodic current is dramatically amplified from 3.58 mA/cm2 to 20.1 mA/cm2 on the regenerated electrode proving the effectiveness of the regeneration approach on enhancing the current density and magnifying the anodic peak. The regeneration of the electrode reduces the electrocatalyst tolerance towards poisoning intermediate carbonaceous species accumulated on the catalyst surfaces and increased the current density with a good stability for more than 5000s.