In situ formed catalysts for active, durable, and thermally stable ammonia protonic ceramic fuel cells at 550 °C

Abstract

Ammonia protonic ceramic fuel cells (NH₃-PCFCs) are promising and attractive energy-conversion devices owing to their high energy density, zero-carbon emission, and safety. The development of NH₃-PCFCs, however, depends largely on the insufficient activity and poor durability of typical Ni-based anodes for ammonia decomposition, especially at low temperatures such as 550 °C. Herein, we report a self-assembled heterostructured Ru_0.95Cu_0.05Ni_x (RCN) catalyst obtained through an in situ reaction between the surface-decorated Ru_0.95Cu_0.05 nanoparticles and the Ni grain in the anode under typical processing conditions. At 550 °C, Ni–BaZr_0.1Ce_0.7Y_0.1Yb_0.1O₃ anode-supported PCFCs with RCN catalysts exhibit a high peak power density of 0.732 W cm⁻² and a significantly enhanced durability of 100 h in NH₃. Moreover, the cells demonstrate improved thermal stability compared with the bare cell during a 31-cycle thermal cycling test in NH₃ between 550 and 700 °C. The enhanced performance is likely attributed to the synergistic effects of Ru and Cu in RCN for NH₃ decomposition, resulting in a more vital interaction of NH₃ than that of the bare anode surfaces, as confirmed by NH₃ thermal conversion, electrochemical performance, and theoretical simulations.