doiSerbia

Electrochemical oxidation of methanol on Pt/(RuxSn1-x)O2 nanocatalyst

Krstajić Mila N. (Faculty of Technology and Metallurgy, Belgrade)
Obradović Maja D. (Institute of Chemistry, Technology and Metallurgy, Belgrade)
Babić Biljana M. (Vinča Institute of Nuclear Sciences, Belgrade)
Radmilović Velimir R. (Faculty of Technology and Metallurgy, Belgrade)
Lačnjevac Uroš Č. (Institute for Multidisciplinary Research, Belgrade)
Krstajić Nedeljko V. (Faculty of Technology and Metallurgy, Belgrade)
Gojković Snežana Lj. (Faculty of Technology and Metallurgy, Belgrade)

The Ru-doped SnO2 powder, (RuxSn1-x)O2, with the Sn:Ru atomic ratio of 9:1 was synthesized and used as a support for Pt nanoparticles (30 mass% loading). The (RuxSn1-x)O2 support and Pt/(RuxSn1-x)O2 catalyst were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy and transmission electron microscopy (TEM). (RuxSn1-x)O2 was found to be two-phase material consisting of probably solid solution of RuO2 in SnO2 and pure RuO2. The average Pt particle size determined by TEM was 5.3 nm. Cyclic voltammetry of Pt/(RuxSn1-x)O2 indicated good conductivity of the sup-port and displayed usual features of Pt. The results of the electrochemical oxidation of COads and methanol on Pt/(RuxSn1-x)O2 were compared with those on commercial Pt/C and PtRu/C catalysts. Oxidation of COads on Pt/(RuxSn1-x)O2 starts at less positive potentials than on PtRu/C and Pt/C. Potentiodynamic polarization curves and chronoamperometric curves of methanol oxidation indicated higher initial activity of Pt/(RuxSn1-x)O2 catalyst compared to PtRu/C, but also a greater loss in the current density over time. Potentiodynamic stability test of the catalysts revealed that deactivation of the Pt/(RuxSn1-x)O2 and Pt/C was primarily caused by the poisoning of Pt surface by the methanol oxidation residues, which mostly occurred during the first potential cycle. In the case of PtRu/C the poisoning of the surface was minor and deactivation was caused by the PtRu surface area loss.

Keywords: methanol oxidation, CO oxidation, platinum, Ru-doped SnO2, electrocatalysis, fuel cell

Projekat Ministarstva nauke Republike Srbije, br. ON-172054