Carbon supported platinum-iridium bimetallic nanoparticles (PtIr/C) for the electrochemical sensing of hydrogen peroxide (H2O2) were developed. Both the cyclic voltammogram (CV) and the amperometric response indicated that PtIr/C possesses a higher oxidation current than either Pt/C or Ir/C over the detection range 0-10 mM at 0.25 V (vs. SCE). The addition of Ir appears to facilitate oxidation kinetics and decrease the competitive adsorption of dioxygen and oxygenated intermediates. These changes were investigated by electrochemical measurements and X-ray absorption near edge spectroscopy (XANES). This study demonstrated that the PtIr/C provide a stable platform for electrochemical sensing of H2O2-derivated biospecies without enzymes and redox mediators. Copyright 2013 Elsevier B.V.