Methanol resistant ruthenium electrocatalysts for oxygen reduction synthesized by pyrolysis of Ru3(CO)12 in different atmospheres

Novel ruthenium electrocatalysts for the oxygen reduction reaction (ORR) were prepared by pyrolysis of Ru3(CO)12 in three atmospheres: neutral (N2), partially oxidative (air) and partially reductive (70:30 N2/H2), at temperatures in the 80–700 °C range. The materials were characterized by FT-IR spectroscopy, X-ray diffraction and scanning electron microscopy. A thermogravimetric analysis of the Ru3(CO)12 precursor in the three atmospheres was also performed. The electrocatalytic properties of the materials were evaluated by rotating disk electrode measurements in 0.5 mol L−1 H2SO4. The kinetic parameters, such as the Tafel slope, exchange current density and charge transfer coefficient, are reported. The catalysts prepared in N2 and N2/H2, in general, show a higher performance than those synthesized in air. In the two nitrogen containing atmospheres, a pyrolysis temperature of 360 °C seems to lead to better electrocatalytic properties for the ORR. The new electrocatalysts are also tolerant to methanol concentrations as high as 2.0 mol L−1.