Highly Effective Ru/BaCeO3 Catalysts on Supports with Strong Basic Sites for Ammonia Synthesis.

BaCeO3‐a and BaCeO3‐b, with strong basic sites, were synthesized by using a co‐precipitation method at different calcination temperatures, and used as supports to evaluate their performance in ammonia synthesis. The ammonia synthesis rate with the 1.25 % Ru/BaCeO3‐a catalyst is 24 mmol g−1 h−1, which is higher than that of 1.25 % Ru/BaCeO3‐b catalyst (18 mmol g−1 h−1) at 3 MPa and 450 °C. Moreover, the performance of the 4 % Cs‐1.25 % Ru/BaCeO3‐a catalyst was further improved to 28 mmol g−1 h−1, and no sign of deactivation was observed after a reaction time of 120 h. The XPS and H2 temperature‐programmed reduction analyses indicated that the Ru/BaCeO3‐a catalyst has more oxygen vacancies than the Ru/BaCeO3‐b catalyst. In addition, the average Ru particle size of the Ru/BaCeO3‐a catalyst is closer to 2 nm than the Ru/BaCeO3‐b catalyst, which promotes the generation of B5‐type sites (the active site for N2 dissociation). The CO2 temperature‐programmed desorption analysis indicates that BaCeO3‐a has a high basic density, which is beneficial for electron transfer to Ru and further facilitates the dissociation of N≡N bonds. [ABSTRACT FROM AUTHOR]