Decorating La2NiO4+δ cathode with silver nanoparticles by infiltration: Enhanced catalytic effect vs negative etching effect

Protonic ceramic fuel cells (PCFCs) are a promising hydrogen economy-oriented technique for energy conversion, but the performance of cathodes needs to be improved due to the sluggish oxygen reduction reaction kinetics. Post-annealing the AgNO 3 solution-infiltrated La 2 NiO 4+δ (LNO) backbones leads to the formation of Ag nanoparticles-decorated LNO composite cathodes, with the oxygen adsorption ability enhanced significantly at the interface between Ag and LNO. Although the acidity of the AgNO 3 solution results in a negative etching effect, it is compensated or even overcome by the enhanced catalytic activity by generating Ag nanoparticles on the surface of LNO. Notably, LNO loaded with 1 wt% Ag achieves the optimal balance, showing the lowest polarization resistance of 0.25 Ωcm 2 at 650 °C, more than five times lower than 1.28 Ωcm 2 for the bare LNO.