Pt/Pd/C catalysts with ultra low platinum content for oxygen reduction reaction

The activity of Pt/Pd/C ETEK catalysts of the core-shell type with an ultralow content of platinum (0.5–15 μg cm−2) based on a commercial palladium catalyst is shown to exceed the activity of commercial Pt/C ETEK catalysts in the oxygen reduction reaction. The activity sharply increases with the decrease in the platinum content down to values corresponding to monolayer and submonolayer of platinum on palladium. This dependence wasn’t observed for the same amounts of platinum deposited on the carbon support Vulcan XC-72. This makes it possible to conclude that the most probable factor responsible for the high catalytic activity of Pt/Pd/C ETEK is the effect of palladium on the electronic properties of platinum rather than the effect of structural modification of the platinum deposit induced by the decrease in the platinum amount deposited on a foreign metal or a carbon support.