Pt-Pd/CeO2-Omc Bimetallic Catalysts for Formic Acid Oxidation

The effects of CeO₂ modification and variation of Pd/Pt ratios on the performance of PtPd/CeO₂-OMC electrocatalysts in oxidation of formic acid is studied. N₂ adsorption analysis shows that the CeO₂ modification increases the surface area of OMC support from 1005 m²/g to 1119 m²/g.  SEM, XRD and TEM analysis reveal that the presence of CeO₂ enhances the uniform dispersion of active metal(s) on the support surface.  Average sizes of the dispersed metal crystals decrease with the increase of Pt mass fraction on CeO₂-OMC.  Electrochemical evaluation of CeO₂ modified Pd/CeO₂-OMC provides 12 % higher anodic current activity than that of unmodified Pd/OMC catalyst.  The peak potential is also shifted more than 83 mV in the negative direction.  In the bimetallic samples, a small amount of Pt with Pd improves the performance of the catalysts significantly. Among the bimetallic catalysts, Pd₃Pt₁/CeO₂-OMC displays superior current density (74.6 mA/cm²), which is 1.61, 1.67 and 28.3 times higher than that of Pd/CeO₂-OMC, Pd₁Pt₃/CeO₂-OMC and Pt/CeO₂-OMC catalysts, respectively.  The bimetallic Pd₃Pt₁/CeO₂-OMC catalyst also shows persistent activity in extended period of runs without any indication of CO poisoning effects.