Electrochemical behaviour of oxygen at nickel nest cathodic material with catalyst La1-xSrxCoO3

The reduction of oxygen in the three phases gas-liquid-solid using a nickel nest as electrode with a La1-xSrxCoO3 (x = 0, 0.3, 0.5, 0.7, 1) series of combined oxides as a catalyst in different electrolytes of acidic H3PO4 or alkaline KOH, NaOH or LiOH solution at a fixed optimum oxygen flow-rate at room temperature was studied by the electrochemical method. The electrochem ical parameters, such as electron transfer coefficient and exchange current density, were also determined. The La1-xSrxCoO3 series of catalysts was sy nthesized by a solid-state reaction. XRD was used to confirm the structure of the catalyst. BET, EDS and resistivity measurements were used to investi gated the electrochemical behaviour of the cathodic reduction of oxygen in the presence of the catalyst. SEM was also used to inspect the change befor e and after the reaction with the catalyst. The electron transfer coefficie nts, beta, from the experiments with the various catalysts in the different alkaline electrolytes were determined as follows: beta(in KOH) > beta(in NaOH) > beta(in LiOH). It was discovered that La1-xSr0.3CoO3 as a catalyst has a higher catalytic activity, a higher specific surface area, lower electrical resistivity, bet ter stability and less agglomeration. Therefore, the above catalyst is the best catalyst for oxygen reduction of those studied. (C) 1999 Elsevier Scie nce B.V. All rights reserved.