Abstract
Differential capacitance measurements in 96%o-phosphoric acid at 160° C have been used to follow the underpotential deposition of copper on supported platinum in a porous electrode. At a potential in the range 0·2–0·3 V versus RHE the capacitance,C, increased as copper deposition proceeded and a plot ofC versust 1/2 was linear during a substantial part of the deposition process. The slope dC/dt 1/2 was proportional to the copper concentration in solution, suggesting that the Cu/Cu2+ pseudocapacitance reflected the quantity of copper deposited and that copper deposition was diffusion controlled. The effective diffusion coefficient estimated from the results was 10−7 cm2 s−1 — some 40 times smaller than the copper ion diffusion coefficient measured separately. At potentials of 0·4 V and above, capacitance measurements could not be used to follow copper deposition because the Cu/Cu2+ pseudocapacitance decayed with time.
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References
K. Kinoshita and P. Stonehart,Electrochim. Acta 20 (1975) 101.
J. A. Bett, K. Kinoshita and P. Stonehart,J. Catalysis 35 (1974) 307.
D. Ferrier, K. Kinoshita, J. McHardy and P. Stonehart,J. Electroanal. Chem. 61 (1975) 233.
K. Klinedinst, J. A. S. Bett, J. MacDonald and P. Stonehart,ibid 57 (1974) 281.
S. Gilman,J. Chem. Phys. 68 (1964) 2098.
H. R. Kunz and G. A. Gruver,J. Electrochem. Soc. 122 (1975) 1279.
J. McHardy, J. Baris and P. Stonehart,J. Appl. Electrochem. 6 (1976) 371.
L. G. Austin and H. Lerner,Electrochim. Acta 9 (1964) 1469.
P. C. Carman, ‘Flow of Gases Through Porous Media,’ Academic Press, New York (1956).
J. Giner and C. Hunter,J. Electrochem. Soc. 116 (1969) 1124.
L. Ramaley and C. G. Enke,ibid 112 (1965) 943.
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McHardy, J. Investigation of hydrophobic porous electrodes. II. Pseudocapacitance changes during underpotential copper deposition. J Appl Electrochem 7, 57–64 (1977). https://doi.org/10.1007/BF00615531
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DOI: https://doi.org/10.1007/BF00615531