Sulfur‐Tolerant Hierarchically Porous Ceramic Anode‐Supported Solid‐Oxide Fuel Cells with Self‐Precipitated Nanocatalyst

A hierarchically porous Sr2Fe1.5Mo0.5O6−δ–Gd0.1Ce0.9O1.95 (SFM–GDC) ceramic anode-supported solid-oxide fuel cell with a GDC electrolyte film was fabricated by freeze-drying tape-casting and drop coating. 3D X-ray computed tomography analysis indicated that the SFM–GDC anode has a high porosity and low tortuosity factor, facilitating gas diffusion in the anode during fuel cell operation. Peak power density of cells with a La0.6Sr0.4Co0.2Fe0.8O3–GDC (LSCF–GDC) cathode can reach 0.22 W cm−2 at 700 °C when using H2 as the fuel and ambient air as the oxidant. The SFM–GDC anode shows excellent sulfur tolerance when using H2 with 50 ppm H2S. SEM analysis demonstrates that the nanocatalyst (iron) can precipitate from the parent SFM phase upon reduction and iron nanoparticles can react with sulfur species to form needle-like nanosulfide. Both the nanocatalyst and sulfide show a graded distribution along the thickness direction, owing to a graded local oxygen chemical potential within the anode.