Oxygen overpotential of graphite-substrate lead dioxide anode

1965 ◽  
Vol 10 (12) ◽  
pp. 1185-1187 ◽  
Author(s):  
M.S.V. Pathy ◽  
H.V.K. Udupa
1989 ◽  
Vol 42 (9) ◽  
pp. 1527 ◽  
Author(s):  
TH Randle ◽  
AT Kuhn

Lead dioxide is a strong oxidizer in sulfuric acid, consequently electrochemical oxidation of solution species at a lead dioxide anode may occur by a two-step, C-E process (chemical oxidation of solution species by PbO2 followed by electrochemical regeneration of the reduced lead dioxide surface). The maximum rate of each step has been determined in sulfuric acid for specified lead dioxide surfaces and compared with the rates observed for the electrochemical oxidation of cerium(III) and manganese(II) on the same electrode surfaces. While the rate of electrochemical oxidation of a partially reduced PbO2 surface may be sufficient to support the observed rates of CeIII and MnII oxidation at the lead dioxide anode, the rate of chemical reaction between PbO2 and the reducing species is not. Hence it is concluded that the lead dioxide electrode functions as a simple, 'inert' electron-transfer agent during the electrochemical oxidation of CellI and MnII in sulfuric acid. In general, it will most probably be the rate of the chemical step which determines the feasibility or otherwise of the C-E mechanism.


1958 ◽  
Vol 105 (2) ◽  
pp. 100 ◽  
Author(s):  
J. C. Grigger ◽  
H. C. Miller ◽  
F. D. Loomis

1989 ◽  
Vol 42 (2) ◽  
pp. 229 ◽  
Author(s):  
TH Randle ◽  
AT Kuhn

The electrolytic oxidation reactions of cerium(III) and manganeseII) in sulfuric acid have been used as probes to investigate the mechanism of the lead dioxide anode. The kinetics observed for such reactions at the lead dioxide surface provide no direct support for the proposal that the lead dioxide anode functions by a sequential 'two-step' mechanism (heterogeneous chemical oxidation of solution species followed by electrochemical oxidation of the reduced lead dioxide surface); rather the kinetics show characteristics similar to those observed previously for the oxidation of cerium(III) and manganese(II) at the platinum electrode, suggesting that the lead dioxide surface functions as a simple, 'inert' electron-transfer agent.


1976 ◽  
Vol 123 (9) ◽  
pp. 1294-1298 ◽  
Author(s):  
K. C. Narasimham ◽  
H. V. K. Udupa

1959 ◽  
Vol 12 (2) ◽  
pp. 127 ◽  
Author(s):  
DFA Koch

The overpotential (n)-log current density (log i) curves for the evolution of oxygen at a lead dioxide anode in 2N H2SO4 both in the absence and presence of cobaltous sulphate in solution have been used to determine the electrode kinetic constants α ; i0 for a series of temperatures and also ΔH0*:. At 25 �C in the absence of cobalt α=O.59, i0= 10-11, and ΔH0*= 15 kcal mole-1 When 13 mg/l cobaltous sulphate is added α= 1.0, i0= 10-15, and ΔH0*:=29 kcal mole-1. Possible mechanisms for the reaction are discussed on the basis of these values and the rate determining steps suggested (where M represents the PbO2 surface) are M +H2O =MOH +H+ +e in the absence of cobalt and 2CoOH++ = 2Co++ +H2O + O in its presence.


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