ELECTROCHEMICAL-BEHAVIOR OF CARBON-MONOXIDE ON ELECTROLYTIC DEPOSITS OF PALLADIUM IN SULFURIC-ACID-SOLUTIONS

Chemisorption of CO and electrooxidation of COads are studied on elect rolytic deposits of Pd. Cyclic voltammetry and potentiostatic current transients are used, along with the time dependences of the open circu it potential and the galvanostatic charging curves. Chemisorption of C O on Pd at different potentials E-r is shown to restructure the electr ical double layer. The potentiostatic transients of the current and th e time dependences of the open circuit potential are explained fairly well by assuming that formation of a monolayer of COads makes the pote ntial of zero total charge shift towards high positive values. The dou ble-layer capacitance of the Pd electrode is shown to decrease conside rably due to chemisorption of CO. Particles of COads force off the Pd electrode surface not only H-ad, but Cu-ad as well, which is shown for the first time. Some factors are discussed that affect the ratio betw een the bridging and linear forms of COads and the COads electrooxidat ion kinetics.