Preparation of PtRuNi/C electrocatalysts by an alcohol-reduction process for electro-oxidation of methanol

PtRuNi/C electrocatalysts with 20 wt% metals loading and Pt:Ru:Ni atomic ratio of 50:40:10 were prepared by an alcohol-reduction process. The electrocatalysts were characterized using energy-dispersive X-ray analysis, X-ray diffraction analysis and thermogravimetric analysis. The electrooxidation of methanol was studied in sulfuric acid solution by chronoamperometry. it was found that when the initial pH of the reaction medium was acidic, only Pt(IV) and Ru(III) ions were reduced, while the reduction of Ni(II) ions did not take place. Changing the pH of the reaction medium by addition of OH- ions resulted in the reduction of Pt(IV), Ru(III)and Ni(II) ions, which crystallized in the face-centered cubic (fcc) structure. This was observed for OH-/metals ratios >= 6, however, under these conditions the metals loading on the carbon support was only half the nominal value. The PtRuNi/C electrocatalyst prepared with OH-/metals = 6 showed superior performance for methanol oxidation at room temperature compared to commercial PtRu/C electrocatalyst. (C) 2009 Elsevier B.V. All rights reserved.