Author(s):
Silva, R. A. 
; Soares, C. O. ; Carvalho, M. D. ; Jorge, M. E. Melo ; Gomes, A. ; Rangel, C. M. ; Pereira, M. I. da Silva
Date: 2013
Persistent ID: http://hdl.handle.net/10400.9/2004
Origin: Repositório do LNEG
Subject(s): LaNiO3 electrodes; Catalysts ; Oxygen reactions
Description
Perovskite-type oxides are potential catalysts for next generation of regenerative fuel cells. In particular, LaNiO3 has been recognised as one of the most promising oxygen electrodes. In this work LaNiO3 perovskite-type oxides, prepared by a self-combustion method [1, 2], have been used for the preparation of porous gas-diffusion electrodes (GDE). Electrodes were prepared on Toray carbon paper (CP) substrates, consisting of a diffusion layer, a catalyst layer and a Nafion® layer. The
gas diffusion layers were prepared using Vulcan XC-72R. The catalyst ink was prepared by suspending the material in isopropanol, stirring the mixture in an ultrasonic bath to thoroughly disperse it. Ink slurries were also pasted onto glassy carbon discs and used as working electrodes for full kinetic studies at potential domains for the oxygen reduction (ORR) and oxygen evolution (OER) reactions. A systematic study on the effect of the oxide loading (OL) on the electrodes surface area was done by cyclic voltammetry. It was found a quasi linear variation between the electrodes surface area and the oxide loading. Roughness values varying from 106±3 to 307±6 were obtained for OL between 1 and 5 mg cm-2 respectively. The results show that the peak current density increases with the increasing on oxide loading as shown in Fig. 1. Higher current densities for ORR were obtained for the electrodes prepared using LaNiO3-based perovskite with partial substitution of Ni by Cu. Stability studies of the GDEs, performed using a pre-defined cycling protocol in 1M KOH, will be discussed together with catalytic activity parameters relevant for their potential use as bifunctional oxygen electrodes.
