SIZE EFFECTS OF ULTRAFINE PALLADIUM PARTICLES ON THE ELECTROCATALYTICOXIDATION OF CO

Effects of palladium particle size on the electrocatalytic oxidation o f carbon monoxide in an acidic solution have been examined by the use of modeled catalyst electrodes (Pd/GC) with a flat and dense glassy ca rbon substrate. The cyclic voltammetry showed that higher overpotentia l is needed to oxidize carbon monoxide on palladium with a decrease in the palladium particle size. With decreasing size of palladium partic les the oxidation of carbon monoxide seems to shift from a one-electro n-transfer controlled mechanism to a two-electron-transfer controlled one. (C) 1997 Elsevier Science B.V.