Highly active internal catalyst promoting the efficient ammonia decomposition and durability of protonic ceramic fuel cells

Abstract

Direct ammonia protonic ceramic fuel cells (DA-PCFCs) have attracted extensive attention by virtue of their high hydrogen content, superior energy density, and zero carbon emissions. However, the practical application of DA-PCFCs is impeded by their unsatisfactory catalytic activity and limited durability. This study aims to evaluate the feasibility of utilizing ammonia solution as a fuel for PCFCs. In the hope of enhancing performance and reducing costs, a low-cost iron catalyst layer was proposed and fabricated within cells, with a structure of NiO–BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb)| NiO-BZCYYb| BZCYYb| PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF)-BZCYYb. The introduction of the iron catalyst layer yields promising results, achieving a remarkable increase (from 165 mW/cm2 to 300 mW/cm2 by 81.8 %) in maximum power density at 600 °C and a significant lengthening of durability. The enhanced electrochemical performance and durability can be attributed to the presence of the iron catalyst layer, which improves the catalytic activity for ammonia decomposition while preventing the formation of nitride.