The oxidation of pure H 2 and H 2 /CO mixture (100 ppm CO) was investigated on Pt nanocatalyst supported on Ru 0.7 Ti 0.3 O 2 (Pt /Ru 0.7 Ti 0.3 O 2 ) by linear sweep voltammetry at a rotating disc electrode in 0.1 M HClO 4 . The results were compared with those on the commercial Pt/C catalyst. It was demonstrated that Pt/Ru 0.7 Ti 0.3 O 2 electrode possesses good conductivity and stability of the supports in the electrochemical experiments. The onset potential of CO ads oxidation on Pt/Ru 0.7

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... i 0.3 O 2 is lower than Pt/C indicating that the Pt nanoparticles are in close contact with Ru atoms from support, which enable bifunctional mechanism and electronic effects to be operable. The influence of the poisoning of Pt/Ru 0.7 Ti 0.3 O 2 and Pt/C catalyst by CO ads on the HOR was examined at several surface coverages ranging from 0 to 0.6. The decrease in HOR current on CO ads poisoned surface in low over-potential region of 0.05-0.50 V is less pronounced on Pt/Ru 0.7 Ti 0.3 O 2 than on Pt/C. This is ascribed to a weakening of the Pt-CO interaction and consequently higher mobility of CO ads on Pt particles contacting Ru from the Ru 0.7 Ti 0.3 O 2 support.