Thermogravimetric and Electrocatalytic Study of Carbon Deposition of Ag‐doped Ni/YSZ Electrodes under Internal CH₄ Steam Reforming Conditions

The effect of Ag addition on Ni/YSZ Carbon tolerance was studied by means of thermogravimetric, catalytic and electrocatalytic experiments. Ni/YSZ activity towards C deposition can be significantly decreased by adding 1 to 5 at.‐% (atomic ratio) Ag with respect to Ni. It was found that the activation energy of CH 4 dissociation was increased from 61 kJ mol –1 on Ni/YSZ to 137 kJ mol –1 on Ni(5Ag)/YSZ. The electrode was significantly improved with regard to its C tolerance, even at a methane to water ratio as high as 4.35, at temperatures ranging between 923–1,023 K. At higher temperature most probably due to Ag evaporation from Ag‐doped Ni/YSZ surface, a severe anode catalytic and electrocatalytic activity degradation was observed.