Physico-chemical and electrochemical properties of Ni perovskite solid oxide fuel cell anode for glycerol oxidation

An investigation of the electrochemical oxidation of glycerol as alternative fuel to hydrogen and methane in a solid oxide fuel cell (SOFC) based on a noble metal-free anode catalyst was carried out. The anode electrocatalyst consisted of a Ni-modified La0.6Sr0.4Fe0.8Co0.2O3 (LSFCO) perovskite. After thermal activation, air treatment at 1100°C followed by reduction at 800°C in H2, Ni was mainly present as ultrafine La2 NiO4 particles homogeneously dispersed on the perovskite surface. The thermal activation also caused a modification of perovskite into a lanthanum depleted structure. The thermal reduction at 800°C determined the occurrence of metallic Ni on the surface. These results were corroborated by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). A suitable power density (327 mW cm-2) was achieved for the electrolyte supported SOFC fed with chemical-grade glycerol in almost dry condition, i.e. steam to carbon ratio (S/C) of 0.2. The highest electrical efficiency (voltage efficiency) approached 50% at the peak power under mild humidification (S/C = 0.2). Whereas an increase of water to glycerol ratio, caused a progressive decrease of voltage efficiency at the peak power down to 44% for S/C = 2.