ZnO-promoted surface diffusion on NiO-Ce0.8Sm0.2O1.9 anode for solid oxide fuel cell
Abstract
Ni1-xZnxO-Ce0.8Sm0.2O1.9 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 H2 on the anode is investigated with a symmetric cell under various H2 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 Ni0·2Zn0·8O- Ce0.8Sm0.2O1.9 anode facilitates H spillover, resulting in the variation of the rate determining step and the highest activity of the anode. The cell with Ni0·2Zn0·8O- Ce0.8Sm0.2O1.9 anode shows the highest performance with both H2 and methanol fuels at 700 °C. ZnO also improves coking resistance of NiO-Ce0.8Sm0.2O1.9 anode.
- Publication:
-
Journal of Power Sources
- Pub Date:
- May 2019
- DOI:
- 10.1016/j.jpowsour.2019.03.088
- Bibcode:
- 2019JPS...423..290Z
- Keywords:
-
- Anode;
- Solid oxide fuel cell;
- ZnO;
- Surface diffusion;
- Methanol fuel