Influence of urea treatment of mesoporous carbons on electrochemical activity of Pt-Ru catalysts for fuel cells

In this work, the mesoporous carbons (MCs) were urea treated to for high nitrogen-containing groups with different amounts of urea and used as carbon supports of Pt-Ru nanoparticle for fuel cells. The surface and structural properties of the carbon supports and Pt-Ru catalysts were characterized by X-ray diffraction (XRD), surface area analyzer, X-ray photoelectron spectroscopy (XPS), elemental analyzer (EA), and inductive coupled plasma-mass spectrometer (ICP-MS). The electrochemical activity of Pt-Ru catalysts was investigated by cyclic voltammetry measurement. As the result, the nitrogen functional groups of carbon supports were increased with an increase in the amount of urea up to 4 g, while the average of Pt-Ru nanoparticle size was decreased owing to the improvement of dispersibility of the Pt-Ru catalysts. The electrochemical activity of the Pt-Ru catalysts was improved by the larger available active surface area due to the increase of nitrogen functional groups. Therefore, it was found that surface treatment using urea could influence the surface characteristic of carbon supports, resulting in enhanced electrochemical activity of the Pt-Ru catalysts of fuel cells.