Kinetics and mechanism of reduction of oxide film on smooth platinum electrodes with hydrogen

✍ Scribed by S. Shibata; M.P. Sumino

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 420 KB
• Volume: 20
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(75)85008-0

✦ Synopsis

The kinetics and mechanism of the reaction of chemisorbed oxide (P1-0) layer (in a smooth Pt electrode with H 2 dissolved in 1 M H,S0 4 solution were investigated under the open circuit condition.

It was found that a monolaver of Pt-0 no the electrode surface is reduced first at a slow rate which is of second order in chemisorbed oxygen in the range 1 > 9 ? 0 .65 and then at a rapid rate which is proportional to (I -nO)s in the range 0.6 >-6 > 0, where 6 is the fraction of the surface covered by oxygen. The factor n, which was constant for the electrode oxidized under a given condition, was assumed to be the number of Pt sites deactivated by each one of the chemisorbed oxygen atoms. For the transiently formed oxide, ,r was estimated tube 1-64 It was also observed that all over the coverage range the reaction rate was proportional to the partial pressure of H i . The variation in reduction rare with the decrease of Ihn coverage was interpreted in terms of change in reduction mechanism from the chemical reaction to the electrochemical reaction .