NH3 decomposition in a proton conducting solid electrolyte cell

The reaction of NH3 decomposition was studied on Ag in a proton conducting double chamber cell-reactor. The proton conductor was a strontia-ceria-ytterbia (SCY) perovskite of the form SrCe0.95Yb0.05O3-alpha. The reaction was studied at 350-700 degrees C and atmospheric total pressure. The proton transference number (PTN) was calculated by simultaneous measurement of the imposed current and the proton flux and it was found to vary between 0.5 and 0.7. The effects of imposed current, temperature and inlet gas composition on the reaction rate and the PTN, were examined. Although the faradaic efficiency (Lambda) remained near unity in all experiments, reaction rate enhancements (rho) as high as 57 were achieved. An up to 90% decrease in the activation energy of the reaction was observed when protons were electrochemically pumped away from the catalyst.