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Anodic oxidation of cuprous sulphide in aqueous solutions

The oxidation of artificial cuprous sulphide electrodes (Cu/S ratio = 1.93) was studied in acidified copper sulphate solutions in the temperature range 20 to 35° C. Rest potential measurements gave V° = 0.490 volts for the electrode or half cell potential. This is within the limits of accuracy of V° for:
Cu₂S —CuS + Cu⁺⁺ + 2e V° = 0.535 + 0.13 volts
The discrepancy was thought to be related to the large Cu deficien in the sulphide. In solutions with pH>4, the rest potential measurements were consistent with the following reaction:
Cu₂S + 2H₂0 —CuS + Cu(OH)₂ + 2H⁺ + 2e
Polarization measurements at low overpotential gave values for the following kinetic parameters:
β, the symmetry factor = 1/2
λ, the number of electrons involved in each act of the
rate determining step = 2
i₀, the exchange current ≈ 2 x 10-⁵ A/cm²
ΔH₀*, the standard heat of activation = 26.5 kcal/mole
CuS was tentatively identified as one of the reaction products. A reaction mechanism was discussed. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

Identiferoai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/37540
Date January 1965
CreatorsFraser, Michael J.
PublisherUniversity of British Columbia
Source SetsUniversity of British Columbia
LanguageEnglish
Detected LanguageEnglish
TypeText, Thesis/Dissertation
RightsFor non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.

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