Electrochemical characterization of Pt/CNF and PtCo/CNF electrospun catalysts for PEM water electrolysis

Proton exchange membrane (PEM) water electrolysis represents a valid technology for hydrogen production by using renewable energy [1]. Higher current density, low cost for hydrogen purification process and low overpotential voltage are some of the main advantages of this method if compared to alkalyne electrolysis. However, high costs related to the outstanding platinum catalyst activity and stability lead to a slow technology introduction into the market. In this respect, electrospinning method was utilized to reduce the platinum loading on carbon based material supports increasing the utilization of noble metal thanks to an appropriate distribution of the noble metal nanoparticles throughout the electrospun samples [2-3] as well as to the introduction of alternative and low cost metals. Therefore, home-made electrocatalysts based on pristine Platinum and Platinum-Cobalt embedded on carbon nanofiber (Pt/CNF and Pt-Co/CNF) are synthesized starting from platinum acetylacetonate and cobalt acetate as precursors. Polyacrylonitrile (PAN) was utilized as polymer precursor for CNF formation. The mixed solution was subjected to electrospinning technique. The obtained electrospun samples were treated to thermal treatments consisting in two different steps, at 270°C in air and at 900°C in inert gas. The physico-chemical properties of Pt/CNF and Pt-Co/CNF samples are investigated by termogravimetry-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM). Electrochemical characterization are carried out in 5 cm2 single cell configuration by using an home-made Ir-RuO2 as negative electrode [4] and a Aquivion membrane as electrolyte.