Conference paper

State of Adsorbed Halide Ions and Their Competitive Adsorption at Oxidized Pt Electrodes

B. E. Conway ; Chemistry Department, University of Ottawa, Ottawa, Canada
D. M. Novak ; Chemistry Department, University of Ottawa, Ottawa, Canada

Abstract

The effects of strongly adsorbed c1-, Br- and I- on the initial
and subsequent stages of surface oxidation of Pt anodes in aq.
H2S04 and HCl04 are investigated over a wide concentration range,
starting at the very low concentrations where significant effects are
just detectable. A micrometer titration procedure is used which
enables many data poin,ts to be obtained so that the forms of
competitive adsorption isotherms for halide ion blbcking of electrodeposition
of OH and 0 species at Pt can be accurately determined.
Related effects in blocking of H adsorption are also evaluated.
Methods are proposed for the analysis of the results in terms
of lateral interaction effects. From this treatment, it is shown that
adsorbed I- in the oxide film loses almost all of its charge, as does
Br-, but c1- remains ionic and thus has much stronger interactions
with itself and electrodeposited OH and 0 species in the developing
oxide monolayer, than does Br- or I-. Thus, from the competitive
adsorption behaviour, information on the electrosorption valence
of c1-, Br- and I- can be obtained, as well as the form of the competitive
adsorption isotherm for each of the halide ions.

Keywords

Hrčak ID:

194571

URI

https://hrcak.srce.hr/194571

Publication date:

5.11.1980.

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