Morphology and catalytic performance of flake-shaped NiO-yttria-stabilized zirconia (YSZ) particles with nanocrystalline YSZ grains

The flake-shaped NiO-yttria-stabilized zirconia (YSZ) particles with nanocrystalline YSZ grains were synthesized using the sucrose-concentrated H ₂SO ₄ dehydration reaction, and their microstructure was characterized by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). To evaluate the properties of the flake-shaped NiO-YSZ particles as the anode materials for solid oxide fuel cells, the reduction temperature of the flake-shaped NiO-YSZ particles and catalytic activity on the methane steam/CO ₂ reforming reactions of the H ₂-reduced particles as well as the electrochemical impedance spectra of the YSZ supported symmetrical cells with the electrodes made from these particles were examined in comparison with the mixed commercial NiO-YSZ. HRTEM revealed that the nanocrystalline YSZ was dispersed in the NiO matrix and distributed on the surface of the flake-shaped NiO-YSZ particles. The catalytic performance of the flake-shaped NiO-YSZ particles was better than that of the mixed commercial NiO-YSZ in both steam reforming and CO ₂ reforming of methane. The symmetrical cell made from the flake-shaped NiO-YSZ exhibited a much lower polarization resistance at the operating temperatures below 800 °C than that made from the mixed commercial NiO-YSZ.