Support effects on the oxidation of ethanol at Pt nanoparticles

The effects of metal oxide supports on ethanol oxidation have been investigated by drop coating Pt nanoparticles onto glassy carbon electrodes coated with thin layers of ruthenium oxide, tin oxide, a mixed Ru + Sn oxide, and onto an indium–tin oxide (ITO) electrode. All four oxide supports exhibited significant co-catalytic effects, with their effectiveness at low potentials increasing in the order Ru oxide < ITO < Ru + Sn oxide < Sn oxide. However, at higher potentials (e.g. 0.4 V vs. SCE) currents were higher for Pt supported on Ru oxide or Ru + Sn oxide than on Sn oxide, revealing mechanistic differences between the roles of Ru and Sn oxide. Although Sn oxide produced very high initial activities, ITO and Ru + Sn oxide provided more stable performances.

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► Ethanol oxidation at Pt nanoparticles is strongly promoted by contact with oxides containing Sn.
► Pure Sn oxide films provide the highest initial activities.
► Mixed RuSn and InSn oxides provide better long term performances.
► Comparisons between the effects of Sn and Ru oxide films reveal differences in their mechanistic roles.