Fig. 5: Thermodynamic properties, electrochemical measurements and micro-characterization of degradation mechanism in NH3-fed PCFC.
From: Ammonia-fed reversible protonic ceramic fuel cells with Ru-based catalyst
a Thermodynamic calculations for NiO reduction by H2 and NH3, and Ni3N formation via NH3 gas and metallic Ni. The figure shows that NH3 is a stronger reducing agent than H2 at temperatures exceeding 275 °C, and that Ni3N formation is thermodynamically unfavorable under typical PCFC operation temperatures. b DC resistance measurement of porous nickel pellet upon non-cracked NH3 exposure at 600 °C; steady performance is observed. c EIS measurement of a porous BCZYYb (with 1 wt% NiO) pellet during exposure to non-cracked NH3 at 600 °C; polarization resistance increases by orders of magnitude over 10 h. d, e TEM-EDS analysis of nano-sized NiO after H2 and non-cracked NH3 exposure respectively. The comparison does not show the formation of Ni3N.
