Influence of Cation Substitutions Based on ABO(3) Perovskite Materials, Sr1-XYXTi1-yRuyO3-delta, on Ammonia Dehydrogenation

Abstract

In order to screen potential catalytic materials for synthesis and decomposition of ammonia, a series of ABO(3) perovskite materials, Sr1-xYxTi1-yRuyO3-delta (x = 0, 0.08, and 0.16; y = 0, 0.04, 0.07, 0.12, 0.17, and 0.26) were synthesized and tested for ammonia dehydrogenation. The influence of A or B site substitution on the catalytic ammonia dehydrogenation activity was determined by varying the quantity of either A or B site cation, producing Sr1-xYxTi0.92Ru0.08O3-delta and Sr0.92Y0.08Ti1-yRuyO3-delta, respectively. Characterizations of the as -synthesized materials using different analytical techniques indicated that a new perovskite phase of SrRuO3 was produced upon addition of large amounts of Ru (>= 12 mol %), and the surface Ru-0 species were formed simultaneously to ultimately yield Ru-z(surface)/Sr0.92Y0.08Ti1-yRuy-zO3-delta and/or Ruz-w(surface)/SrwRuwO3/Sr0.92-wY0.08Ti1-yRuy-zO3-delta. The newly generated surface Ru-0 species at the perovskite surfaces accelerated ammonia dehydrogenation under different conditions, and Sr0.84Y0.16Ti0.92Ru0.08O3-delta exhibited a NH3 conversion of ca. 96% at 500 degrees C with a gas hourly space velocity (GHSV) of 10 000 mL g(cat)(-1) h(-1). In addition, Sr0.84Y0.16Ti0.92Ru0.08O3-delta further proved to be highly active and stable toward ammonia decomposition at different reaction temperatures and GHSVs for > 275 h.