The presented work describes a process for producing a mixed-conducting SOFC cermet anode through the in situ reduction of a ternary oxide. A porous nickel tungstenate (NiWO4) was screen-printed and bonded onto an yttrium-stabilized zirconia (YSZ) electrolyte-supported SOFC by treatment at 1000 degrees C for 1 h. An (La,sr)MnO3/Ce0.9Gd0.1O2(LSM/GDC) was utilized as the cathode with the NiWO4 acting as the anode for the SOFC. The similar to 1-cm diameter fuel cell with a similar to 100-mu m thick YSZ electrolyte was tested in H-2 fuel at 800 degrees C. During the insertion of the H-2 fuel, the NiWO4 was reduced to form a Ni/WOx cermet composite that consisted of a fine mixture of Ni-nanoparticles dispersed over the porous WO, support structure. A maximum power density of similar to 104 mW cm(-2) was attained for the reduced NiWO4 anode, even with an un-optimized and dense microstructure, on an electrolyte-supported cell. The power density was increased to similar to 165 mW cm(-2) with the incorporation of GDC powder into the NiWO4 anode. The same NiWO4/GDC composite was tested within a fuel stream of H-2 containing 10 ppm PH3. The cell's degradation rate was 0.006 V h(-1) for 5 h at 750 degrees C, which is similar to that observed for conventional Nil YSZ cermets. (C) 2013 Elsevier B.V. All rights reserved.