ZnO-promoted surface diffusion on NiO-Ce0.8Sm0.2O1.9 anode for solid oxide fuel cell

Ni 1-x Zn x O-Ce 0.8 Sm 0.2 O 1.9 is studied as an anode material for solid oxide fuel cells with hydrogen and methanol as fuels. After reduction, Zn is incorporated into the lattice of Ni when x is less than 0.5, while NiZn alloy accompanied with ZnO is formed when x reaches 0.8. The electrochemical oxidation process of H 2 on the anode is investigated with a symmetric cell under various H 2 partial pressures. The addition of Zn increases the electron cloud density of Ni and thus weakens the adsorbing strength of H on Ni, accelerating the surface diffusion of H species, which is the rate determining step when the content of Zn is lower than 0.5. ZnO in the reduced Ni 0·2 Zn 0·8 O- Ce 0.8 Sm 0.2 O 1.9 anode facilitates H spillover, resulting in the variation of the rate determining step and the highest activity of the anode. The cell with Ni 0·2 Zn 0·8 O- Ce 0.8 Sm 0.2 O 1.9 anode shows the highest performance with both H 2 and methanol fuels at 700 °C. ZnO also improves coking resistance of NiO-Ce 0.8 Sm 0.2 O 1.9 anode.