A new efficient and anti-sintering perovskite oxide-based internal catalyst for tubular direct-ammonia protonic ceramic fuel cells

Ammonia as a promising carbon-free hydrogen energy carrier with high volumetric density and liquefaction efficiency can be directly utilized in intermediate-temperature proton ceramic fuel cells (PCFCs). The introduction of internal catalysts in direct-ammonia PCFCs (DA-PCFCs) can effectively promote the ammonia decomposition reaction in the anode chamber and prevent the ammonia corrosion on the Ni particles in the cermet anode simultaneously. In this work, a new efficient and anti-sintering perovskite oxide-based internal catalyst (Ba(Zr_0.1Ce_0.7Y_0.1Yb_0.1)_0.9Ni_0.05Ru_0.05O_3-δ, BZCYYbNRu) is designed and fabricated for tubular DA-PCFCs to boost the ammonia utilization efficiency and the cell stability. The metal-site-free BZCYYbNRu catalyst exhibits a high ammonia conversion of above 98.2 % and a promising operational durability of 200 h at 600 °C. As compared with the pristine tubular cell without catalyst, the cell with such BZCYYbNRu internal catalyst exhibits a 16 % increase in the peak power densities from 418 to 483 mW cm⁻² at 700 °C and a stable operation of over 160 h due to the effectively inhibited sintering of Ni particles in the cermet anodes and active metal sites in the conventional supported internal catalysts. This study provides a new metal-site-free, highly active and anti-sintering internal catalyst to realize high-efficiency and durable tubular DA-PCFCs.