Internal reforming over nickel/zirconia anodes in SOFCS oparating on methane: influence of anode formulation, pre-treatment and operating conditions

Internal methane reforming over nickel/zirconia cermet anodes has been stud ied in derail using a thin-walled extruded zirconia tubular SOFC reactor. T he influence of anode formulation, anode pre-treatment, operating temperatu re and methane/steam ratio on the reforming characteristics, resistance to carbon deposition and durability of the anode have been investigated under actual operating conditions. Post-reaction TPO has been used to determine t he amount of carbon deposition and its strength of interaction with the ano de. A 90-vol.% nickel/zirconia anode shows higher activity than a 50-vol.% Ni anode at higher reforming temperatures, and shows very good durability. Pre-reducing the anodes in H-2 at 1173 K leads to a more active reforming c atalyst, Carbon is removed from the anodes in two processes during TPO, sug gesting two types of carbon species. As the reforming temperature increases both carbon types are removed at higher temperature, and there is an incre ase in the relative population of the more strongly bound form of carbon. ( C) 2000 Elsevier Science S.A. All rights reserved.