Author(s): Fiuza, Raigenis da Paz ; Silva, Marcos Aurélio da ; Boaventura Filho, Jaime Soares ; Fiuza, Raigenis da Paz ; Silva, Marcos Aurélio da ; Boaventura Filho, Jaime Soares
Date: 2013
Origin: Oasisbr
Subject(s): Anode; Carbon deposition; Ethanol; Solid oxide fuel cell (SOFC); Iron–nickel catalyst; Reforming
Texto completo: acesso restrito. p.11216-11228
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Electrocatalysts based on Fe–Ni alloys were prepared by means of modified Pechini and physical mixture methods and using on a composite of Yttria Stabilized Zirconia (YSZ) and Gadolinia-Doped Ceria (GDC) as support. The former method was based on the formation a polymeric precursor that was subsequently calcined; the later method was based on the mixture of NiO and the support. The resulting composites had 35 wt.% metal load and 65 wt.% support (70 wt.% YSZ and 30 wt.% GDC mixture) (cermets). The samples were then characterized by Temperature-Programmed Reduction (TPR) and X-Ray Diffraction (XRD) and evaluated in the ethanol steam reforming at 650 °C for 6 h in the temperature range of 300–900 °C. The XRD results showed that the bimetallic sample calcined at 800 °C formed a mixed oxide (NiFe2O4) with a spinel structure, which, after reduction in hydrogen, formed Ni–Fe alloys. The presence of Ni was observed to decrease the final reduction temperature of the NiFe2O4 species. The addition of iron to the nickel anchored to YSZ–GDC increased the hydrogen production and inhibited carbon deposition. The resulting bimetallic 30Fe5Ni sample reached an ethanol conversion of about 95% and a hydrogen yield up to 48% at 750 °C. In general, ethanol conversion and hydrogen production were independent of the metal content in the electrocatalyst. However, the substitution of nickel for iron significantly reduced carbon deposition on the electrocatalyst: 74, 31, and 9 wt.% in the 35Ni, 20Fe15Ni, and 30Fe5Ni samples, respectively.
