INQUINOA   21218
INSTITUTO DE QUIMICA DEL NOROESTE
Unidad Ejecutora - UE
artículos
Título:
Ammonia oxidation on electrodeposited Pt–Ir alloys
Autor/es:
E. MORAN,C.CATTANEO, H. MISHIMA,B.A..LÓPEZ DE MISHIMA,S.P.SILVETTI, J.L.RODRIGUEZ, E.PASTOR
Revista:
JOURNAL OF SOLID STATE ELECTROCHEMISTRY (PRINT)
Editorial:
Springer -Verlag ( on line 18 de sitiembre 2007)
Referencias:
Lugar: Heidelberg; Año: 2008 vol. 12 p. 583 - 589
ISSN:
1432-8488
Resumen:
Received: 26 September 2006 / Revised: 7 June 2007 / Accepted: 8 August 2007 / Published online: 18 September 2007 # Springer-Verlag 2007Springer-Verlag 2007 Abstract Ammonia electro-oxidation on Pt–Ir alloys hasbeen studied applying cyclic voltammetry and differentialelectrochemical mass spectrometry (DEMS), and the resultswere compared with pure Pt. Bimetallic alloys wereprepared by electrodeposition and characterized using Xray diffractometry (XRD) and Auger spectroscopy, before and after oxidation of ammonia. Pt/Ir atomic composition was 70:30 obtained from 1:1 solutions. Substitution alloys were established where Ir atoms replace Pt positions in the face-centered cubic structure. Preferential crystal orientations were detected in the electrodeposits with the developmentof a crystallographic texture. DEMS showed that N2 is the main product during ammonia oxidation for both Pt and Pt–Ir, but the formation of nitrogen oxides is observed for E>0.8 VRHE. The yield of N2 is higher for thealloy, which also displays lower poisoning of the surface when increasing ammonia concentration. These results confirm Pt–Ir alloys as alternatives to Pt electrodes concerning ammonia oxidation. Finally, it was observed that XRD patterns, as well as texture coefficient values, change after using the electrodeposits for ammonia oxidation, with the less compact planes the more affected ones.