Effect of secondary metal catalysts on butane internal steam reforming operation of thin-film solid oxide fuel cells at 500–600 °C

[Display omitted] •Pd, Ru, and Cu are studied as secondary fuel catalysts of solid oxide fuel cell.•Fuel flexibility of low-temperature solid oxide fuel cell (LT-SOFC) is studied.•Butane direct internal stream reforming (DISR) of LT-SOFC at 5–600 °C is assessed.•With Ru, 973 mW cm−2 peak power at 600 °C was achieved (∼100 % C4H10 conversion).•Cu-cell yielded comparable peak power as that of Ru-cell at 500 °C, 310 mW cm−2. Pd, Ru, and Cu secondary catalysts were incorporated into the nickel-yttria-stabilized zirconia nanostructured-anode functional layer (nano-AFL) of solid oxide fuel cells (SOFCs) by a combination of pulsed-laser-deposition and sputtering. The activity of these catalysts for direct internal steam reforming (DISR) of n-butane at the SOFC unit cell level were investigated at low temperatures (500–600 °C) by comparing the electrochemical performance among the Ref-cell (the cell without catalyst at the nano-AFL) and Pd-, Ru-, and Cu-cell (the cells with Pd-, Ru- and Cu- incorporated at the nano-AFL). The steam-to-carbon ratio (SCR) and the operating temperature were varied and the effect on DISR of n-butane in the Ref-, Pd-, Ru-, and Cu-cell were systematically studied. Secondary catalyst incorporation appears to enhance the electrochemical reaction and thermochemical reactions, such as steam reforming and water-gas-shift reactions, which results in the cell performance improvement at all tested conditions in comparison with that of the Ref-cell.