Work

Characterization of (La[sub 1−x]Sr[sub x])[sub s]MnO[sub 3] and Doped Ceria Composite Electrodes in NO[sub x]-Containing Atmosphere with Impedance Spectroscopy

Year: 2010

Type: article

Abstract: This study used electrochemical impedance spectroscopy (EIS) to characterize composite metal oxide electrodes in atmospheres containing NO, NO 2 , and O 2 . Symmetrical cells with electrodes of ( La 1 − x Sr x ) s MnO 3 [ ( x , s ) = ( 0.15 , 0.9 ) and (0.5, 0.99)] and doped ceria [ Ce 0.9 Gd 0.1 O 2 and Ce 1 − x Gd x O 2 ( x = 0.1 , 0.2 ) ] were subjected to EIS while varying the temperature (from 300 to 600 ° C ), the composition of the atmosphere, and the gas flow. The impedance spectra were fitted to equivalent circuits, and common arcs were identified and sought related to physical and chemical processes. The electrodes had a much lower polarization resistance ( R p ) when NO or NO 2 was present in the atmosphere at low temperatures ( 300 – 400 ° C ) than in air. The impedance spectra for electrodes in 1% NO in Ar were dominated by a low frequency arc at high temperatures ( 500 – 600 ° C ) . This arc seemed to be a type of conversion arc, which is related to a gaseous intermediate (possibly NO 2 ), formed from NO, through which the electrode reaction occurs. Indications were found that the electrodes are not electrochemically active toward NO around open-circuit voltages.

Source: Journal of The Electrochemical Society

DOI: 10.1149/1.3327892

Authors: R. M. L. Werchmeister, K. Kammer Hansen, M. Mogensen

Institution: Technical University of Denmark

Language: English

Topic: Catalytic Processes in Materials Science

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: bronze

Funders: Strategiske Forskningsråd, Danmarks Tekniske Universitet

Award: G4904706243