Accession Number : AD0610265

Title :   ELECTROCHEMICAL OXIDATION OF SATURATED HYDROCARBONS.

Descriptive Note : Interim technical rept. no. 2, 1 May-30 Oct 64,

Corporate Author : TYCO LABS INC WALTHAM MASS

Personal Author(s) : Makrides,A. C. ; Brummer,S. B. ; Dienst,M.

Report Date : 30 OCT 1964

Pagination or Media Count : 52

Abstract : A study of the behavior under N2 and propane gases, of smooth Pt electrodes in concentrated phosphoric acid electrolytes was carried out. The adsorption of propane on Pt from concentrated H3PO4 at 80C. was studied with anodic and cathodic charging curves. Neither of these by itself was found to give a reliable estimate of the adsorbate concentration, but together they provided an insight into the character of the adsorbed species. Initial adsorption is probably on a single site but substantial further material is adsorbed on 3 sites, except at low potentials. The stoichiometry of this 3 site adsorbate corresponds to direct adsorption of propane. At longer times of adsorption, the propane degrades and is partially oxidized. This adsorbed product releases about two electrons per Pt surface site atom during its oxidation at high potentials. Coverage with this species is high at some potentials, and is potentialdependent. The rate of adsorption is probably controlled by the rate of diffusion of propane to the electrode. Current potential curves for the oxidation of C3H8 on smooth Pt, from 85% H3PO4, at 130C, were also studied. The oxidation rate, at low potentials, is activationcontrolled, with a Tafel slope of about 2.3 RT/F. At higher potentials, the oxidation rate is controlled by diffusion of propane.

Descriptors :   (*ELECTROCHEMISTRY, HYDROCARBONS), (*HYDROCARBONS, OXIDATION), (*FUEL CELLS, HYDROCARBONS), NITROGEN, ALIPHATIC COMPOUNDS, PHOSPHORIC ACIDS, ELECTROLYTES, PLATINUM, ELECTRODES, ABSORPTION

Distribution Statement : APPROVED FOR PUBLIC RELEASE