Catalytic activity of Ni-YSZ-CeO2 anode for the steam reforming of methanein a direct internal-reforming solid oxide fuel cell

As one of the key technologies in the development of a direct internal-refo rming solid oxide fuel cell, catalytic activity and stability of a Ni-YSZ-C eO2 anode on a zirconia electrolyte for the steam reforming of methane was investigated by experiments using a differential fuel cell reactor. The eff ects of the partial pressure of CH4, H2O and H-2, and temperature as well a s the electrochemical oxidation on the catalytic activity were analyzed. It was found that the catalytic activity of the Ni-YSZ-CeO2 anode was higher than that of the Ni-YSZ reported especially at low temperature. A deteriora tion of the catalytic activity of the anode was observed at low P-H2 and hi gh P-H2O atmosphere, and also at high current densities. This might be caus ed by the oxidation of the Ni surface by H2O in the reaction gas and that p roduced by the anodic reaction. A rate equation for a fractional function f or the steam reforming on open circuit was also proposed. (C) 2001 Elsevier Science B.V. All rights reserved.