Effect of annealing temperature on the structure and coke-resistance of nickel–iron bimetallic catalytic layer for in situ methane steam reforming in SOFC operation

•An intermediate FeNi3 phase forms in all Ni0.75Fe0.25 catalysts in present work.•The catalyst annealed at 705 °C has smallest calculated surface energy.•The catalyst annealed at 705 °C also exhibits the best coke resistance in methane.•The cell with catalyst layer annealed at 705 °C has the best stability in methane.

In this paper, the effect on coke formation of adding a Ni0.75Fe0.25 catalyst layer to the anode side of a fuel cell running on methane is investigated. The formation of an intermediate FeNi3 phase can be observed in catalysts annealed at different temperatures. The catalyst annealed at 705 °C has the smallest calculated surface energy and grain size among all catalysts annealed at different temperatures. In addition, the O2-TPO profiles and Raman spectra of spent anode material reveal that the catalyst annealed at 705 °C has the best coke resistance among all catalysts. Moreover, the cell with catalyst layer annealed at 705 °C, under a current density of 600 mA cm−2 at 650 °C, experiences a decrease of 10% after operating in methane for 260 min, which is much more stable than that without catalyst layer (a decrease of 50%).