A robust fuel cell operated on nearly dry methane at 500 °C enabled by synergistic thermal catalysis and electrocatalysis

Solid oxide fuel cells (SOFCs) are potentially the most efficient technology for direct conversion of hydrocarbons to electricity. While their commercial viability is greatest at operating temperatures of 300–500 °C, it is extremely difficult to run SOFCs on methane at these temperatures, where oxygen reduction and C–H activation are notoriously sluggish. Here we report a robust SOFC that enabled direct utilization of nearly dry methane (with ~3.5% H2O) at 500 °C (achieving a peak power density of 0.37 W cm−2) with no evidence of coking after ~550 h operation. The cell consists of a PrBa0.5Sr0.5Co1.5Fe0.5O5+δ nanofibre-based cathode and a BaZr0.1Ce0.7Y0.1Yb0.1O3–δ-based multifunctional anode coated with Ce0.90Ni0.05Ru0.05O2 (CNR) catalyst for reforming of CH4 to H2 and CO. The high activity and coking resistance of the CNR is attributed to a synergistic effect of cationic Ni and Ru sites anchored on the CNR surface, as confirmed by in situ/operando experiments and computations. Solid oxide fuel cells are most commercially viable when run at low temperatures, but this makes it challenging to achieve high performance with hydrocarbon fuels. Here the authors report a fuel cell running at 500 °C on nearly dry methane that incorporates a Ni–Ru–CeO2-based reforming catalyst, achieving high power densities and coking resistance.