Kinetics of the oxidation of Pu(IV) by manganese dioxide

2000 ◽  
Author(s):  
A. Morgenstern
1974 ◽  
Vol 6 (5) ◽  
pp. 438-442 ◽  
Author(s):  
MASAYOSHI KOBAYASHI ◽  
HARUO KOBAYASHI

1985 ◽  
Vol 55 ◽  
Author(s):  
Ellen M. Kelliher ◽  
Timothy L. Rose

ABSTRACTHydrous manganese dioxide films are being investigated as a new redox material for the active surface of intracortical stimulation electrodes. The films are electrodeposited at room temperature on Pt substrates from a neutral solution of manganese acetate. The electrochemical properties of the films have been evaluated by cyclic voltammetry in neutral saline solutions buffered with bicarbonate. The films undergo a reversible charge injection reaction represented asThe results obtained in electrolytes of different buffer concentrations indicate the film is able to store the most charge in solutions having the lowest buffer capacity. The kinetics of the redox reaction thus favor operation in an acidic or basic environment in agreement with earlier published results. Two different mechanisms are proposed to explain the rate enhancement at the different pH's. In acidic electrolytes the reaction proceeds by dissolution of the film, while in alkaline solutions the rate determining step of proton diffusion in the solid film is increased. For neural stimulation, therefore, electrodes with manganese dioxide films should be pulsed cathodically to insure a neutral or alkaline environment around the electrode and minimize dissolution of the film.


2015 ◽  
Vol 9 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Xiaoliu Huangfu ◽  
Yaan Wang ◽  
Yongze Liu ◽  
Xixin Lu ◽  
Xiang Zhang ◽  
...  

2018 ◽  
Vol 53 (1) ◽  
pp. 146-156 ◽  
Author(s):  
Xiaoliu Huangfu ◽  
Chengxue Ma ◽  
Ruixing Huang ◽  
Qiang He ◽  
Caihong Liu ◽  
...  

1957 ◽  
Vol 10 (2) ◽  
pp. 150 ◽  
Author(s):  
DFA Koch

The kinetics of the reaction between manganese dioxide and ferrous ion in acid solution have been investigated by using the potential of the ferrous-ferric couple as a measure of the extent of reaction. The experimental conditions were such that the reaction rate was independent of ferrous, ferric, manganous ions, and acid concentrations and the agitation was sufficient to prevent bulk diffusion in the solution from being a rate-determining factor. The reaction rate of sized samples of pyrolusite and γ-MnO2 in ferrous sulphate solution was proportional to the surface area of the solid and was constant (i.e. " zero-order ") until 50 per cent. of the solid was consumed. γ-MnO2 reacted about twice as rapidly as the pyrolusite. The reaction occurred most readily at certain active sites on the particles and appeared to proceed along crystal boundaries in such a manner that the active surface area was not significantly changed during the first half of the reaction. In ferrous perchlorate the reaction rate of 10 μ diameter pyrolusite was about one-hundredth of that in sulphate and the reaction appeared to occur at a more even rate over the whole surface of the particle so that the zero-order law was no longer obeyed. Activation energies of 7.4 and 5 kcal in sulphate and perchlorate respectively, for the temperature range 18 to 40 �C, suggest that the difference in rate is a result of a change in the entropy factor of the Arrhenius equation. It is suggested that this difference in rate may result from the activation, by sulphate ions, of a less reactive lower oxide of manganese which is formed on the surface.


2011 ◽  
Vol 81 (4) ◽  
pp. 704-709 ◽  
Author(s):  
D. E. Chirkst ◽  
O. V. Cheremisina ◽  
M. A. Sulimova ◽  
A. A. Kuzhaeva ◽  
P. V. Zgonnik

Sign in / Sign up

Export Citation Format

Share Document