Rapid degradation phenomenon of NiCu-Ce0.8Gd0.2O1.9 anode at high p(H2O) in different concentrations of dry methane

► Rapid degradation of NiCu-CGO was found in different concentrations of CH4. ► Re-oxidation of Ni and/or rapid sintering of Ni should result in the degradation. ► Degradation occurred as p(H2O)/p(CH4) ratio over a threshold value.