Influence Of Dopant Concentration Research Articles

Influence of dopant concentration on oxygen reduction for highly doped zirconias

The ionic conductivity of the (ZrO 2) 1− x (Y 2O 3) x system, where x is equal to 9, 15 and 25 mol%, has been studi ed. The conductivity decreases as x increases for the investigated compositions in the 300–1000°C temperature range. The electrochemical behavior of Pt-paste electrodes on these solid electrolytes is also examined. At low polarizations, the oxygen reaction rate depends on the electrolyte composition and varies similarly to the ionic conductivity, indicating the active participation of the electrolyte in the rate-determining step. At cathodic overpotentials lower than about −100 mV/air, a sudden increase of the current is observed. The value of the overpotential beyond which this transition occurs decreases as x increases.

Influence of dopant concentration on the electronic conductivity of nonstoichiometric yttria-doped ceria

The influence of dopant concentration on the electrical conduction of nonstoichiometric yttria-ceria solid solutions was studied. Electrical conductivity was measured by impedance spectroscopy and the deviation from stoichiometry controlled by electrochemical reduction of the oxide. The stoichiometry ratio (5×10 −4−1.5×10 −2) was determined using an electrochemical zirconia gauge. The observed temperature dependence of the electronic conductivity is consistent with a small-polaron hopping mechanism. The activation energy of mobilities increases with the yttria concentration. This could be interpreted by interactions between the injected electrons and the oxygen vacancies created by the doping.

The Influence of Dopant Concentration on the Oxidation of N‐Type GaAs in H 2 O

not Available.