Characterization of NiO-Al2O3 composite and its conductivity in biogas for solid oxide fuel cell

Abstract

NiO-Al2O3 nanocomposite has been synthesized by mixing combustion synthesized powders. The nanocomposite is an effective anode/anode functional layer for intermediate temperature solid oxide fuel cells. The TEM of NiO and Al2O3 revealed spherical particles of 30 nm and platelets of 70 nm, respectively. The XRD analysis of NiO-Al2O3 composite sintered at 900 °C showed presence of cubic NiO and rhombohedral α-Al2O3 which were chemically stable. However, above 1200 °C NiAl2O4 started to appear. The conductivity of NiO-Al2O3 was the highest in hydrogen (4.3 × 10-3 S/cm at 600 °C). In biogas, the conductivity was 3.2 × 10-3 S/cm with the activation energy of 0.67 eV. The stability of the composite in biogas was also examined.