Entropy-Modulated Oxide–Metal Catalyst Architectures for Direct Ammonia Protonic Ceramic Fuel Cells

Abstract Protonic ceramic fuel cells (PCFCs) operating on NH 3 present a promising carbon-free energy pathway, yet their performance is often constrained by limited catalytic activity and degradation of conventional Ni-based anodes. Here, we report a high-entropy perovskite catalyst, Sr 2 Fe 1 Mo 0.2 Mn 0.2 Cr 0.2 Cu 0.2 Ni 0.2 O 6- δ (SFMMCCN), employed as an anode catalyst layer in direct ammonia-fed PCFCs. Upon reduction, SFMMCCN undergoes in situ exsolution of Ni–Fe–Cu alloy nanoparticles wi