On the reduction of oxygen at platinum—oxygen alloy diaphragm electrodes

✍ Scribed by J.P. Hoare

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 693 KB
• Volume: 20
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(75)90004-3

✦ Synopsis

The steady-state reduction ofoxygen in O,-saturated 2 N H,SO, solution was obtalned at constant current on the front side of a Pt fo11 diaphragm before and after strong anodization of the back side. Strong anodization converts the Pt to a Pt-0 alloy. In all cases, the overvoltage for O2 reduction was less at the PI-O alloy than at the Pt cathode. This enhanced catalytic activity of Pt contaming dissolved oxygen is mterpreted in terms of the band approxlmatlon model of metals. The dissolved oxygen in such high concentrations generates a &band in the alloy which interacts with the 5d-and 6s.bands of the Pt. Electrons spill into the Sd-band causing a raising of the Fermi level of the metal with respect to the energy distribution ofadsorbed species on the electrode surface. Consequently, it requires less cathodic polarization to transfer electrons from the metal to the species adsorbed on the metal surface by quantum mechanical tunnelling or hy passing over the potential energy harrier.