Electrocatalytic properties of novel ruthenium-based compounds for the oxygen reduction reaction in 0.5 M H2SO4: Effects of the synthesis atmosphere and temperature

摘要

Novel ruthenium-based electrocatalysts have been synthesised by pyrolysis of triruthenium dodecacarbonyl [Ru-3(CO)(12)] at different temperatures (180, 210, 240, 260 and 280degreesC), under nitrogen atmospheres (N-2 and 96:4 N-2/H-2) for the first time; syntheses in air were also performed, for comparison purposes. The compounds were characterised by X-ray diffraction, micro-Raman and FTIR spectroscopies. The oxygen reduction reaction (ORR) in 0.5 M H2SO4 was studied at 25 degreesC, using a rotating disk electrode. The Tafel slope (b) and exchange current density values (j(o)) are reported as a function of the synthesis atmosphere and temperature; the results show that the electrocatalytic activity of the materials obtained under nitrogen atmospheres (N-2 and N-2/H-2) is higher than that of the compounds prepared in air and therefore, they are good candidates for their use as cathodes in PEM fuel cells.