Comparative study on ammonia oxidation over Ni-based cermet anodes for solid oxide fuel cells

• Ni–GDC shows higher catalytic activity for ammonia decomposition than Ni–YSZ.
• GDC surface demonstrates a higher number of basic sites compared with YSZ.
• Higher production of H2 from NH3 decomposition over Ni–GDC anode was confirmed.
• Ni–GDC microstructure dependence of the performance of direct NH3 SOFCs was proved.

In the current work, we investigate the performance of solid oxide fuel cells (SOFCs) with Ni‒yttria-stabilized zirconia (Ni–YSZ) and Ni‒gadolinia-dope ceria (Ni–GDC) cermet anodes fueled with H2 or NH3 in terms of the catalytic activity of ammonia decomposition. The cermet of Ni–GDC shows higher catalytic activity for ammonia decomposition than Ni–YSZ. In response to this, the performance of direct NH3–fueled SOFC improved by using Ni–GDC anode. Moreover, we observe further enhancement in the cell performance and the catalytic activity for ammonia decomposition with applying Ni−GDC anode synthesised by the glycine–nitrate combustion process. These results reveal that the high performance of Ni–GDC anode for the direct NH3–fueled SOFC results from its mixed ionic–electronic conductivity as well as high catalytic activity for ammonia decomposition.