Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract In order to demonstrate the usefulness of gassymmetrical galvanic ZrO2 solid electrolyte cells for the determination of NO, cell tensions caused by catalytically different active electrodes and thereby different oxygen partial pressures in N2/NO mixtures with a low oxygen concentration (〈50 vol.-ppm) were measured in the temperature range of 500 to 800°C. Separate investigations demonstrated that the catalytic activity of Pt decreases with increasing sinter temperature (1000 to 1300°C), but is higher than the activity of perovskite type oxides La1−xSrxMeO3 (x=0.1.... 0.5; Me=Co, Mn, Fe, Cr). The activity of the perovskites decreases in the order Co〉Mn ≈ Fe〉Cr. Between different Pt electrodes changes of cell tension were measured when alternating between pure and NO containing nitrogen (e.g. 19.7 mV with 0.4 vol.-% NO). Cells with a Pt electrode and a perovskite electrode produce higher changes of the cell tension, but without going to zero in pure nitrogen due to own oxygen potentials of the mixed oxides.
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