Influence of H2O2 treatment on electrochemical activity of mesoporous carbon-supported Pt-Ru catalysts

In this report, we describe the preparation of OMC (ordered mesoporous carbon) via a conventional templating method using mesoporous silica (SBA-15) as a Pt-Ru catalyst support for use in fuel cells. The influence of surface treatment of the carbon supports on the electrochemical properties of Pt-Ru/OMC was investigated by exposing the surface to hydrogen peroxide at concentrations of 0, 15, 30, 40, and 50 wt%. X-ray photoelectron spectroscopy (XPS) revealed that surface treatment changed the surface chemistry of the OMC samples considerably and introduced surface oxygen functional groups including C-O, CO, OC-O-H, and CO32−. The numbers of these functional groups increased with increasing concentration of H2O2 used in the surface treatment, while the average Pt-Ru nanoparticle size decreased owing to their improved dispersibility. Using CV (cyclic voltammetry), we determined that the electrochemical activity of the Pt-Ru catalyst increased with increasing H2O2 concentration used for surface treatment, up to 40 wt%, due to the introduction of oxygen functional groups. Based on these results, we have established that surface treatment influences the surface properties of OMC materials, resulting in improved electrochemical activity of catalysts for fuel cells.