Promotion of Low-Temperature Catalytic Activity of Ru-Based Catalysts for Ammonia Decomposition via Lanthanum and Cesium Codoping

A series of Ru-based catalysts including Ru/Al2O3, RuLa/Al2O3, RuCs/Al2O3, and RuLaCs/Al2O3 were synthesized via the wet impregnation method, which were then used for hydrogen production from ammonia decomposition. Of the catalysts prepared, RuLaCs/Al2O3 exhibited the highest low-temperature catalytic activity and greatest stability, achieving a NH3 conversion of >99% at the temperature as low as 450 °C. It was discovered that the addition of La and Cs was able to promote the recombinative desorption of surface nitrogen atoms at active sites through the role of electron donor, thus promoting ammonia decomposition. The synergistic effect of La and Cs was thought to be the reason for significantly enhancing the catalytic performance of the catalyst. The continuous tests of more than 100 h indicated no activity deterioration for the developed catalysts, demonstrating an excellent stability and great potential for future commercial applications.