Development of highly active and stable ammonia synthesis catalyst under low temperatures
Profs. Hosono, Hara, Kitano, Abe and Dr. Inoue found that ruthenium nanoparticles immobilized on calcium amide (Ca(NH2)2) function as an efficient catalyst for ammonia synthesis at 300 ℃ and the catalytic activity is more than 10 times higher than that of the highest performance Ru catalysts reported so far. In addition, 3% Ba-doped Ca(NH2)2 supported Ru catalyst exhibited excellent stability during reaction for 700 h (almost 1 month).
Ammonia is mainly consumed as a fertilizer in crop production and has attracted much attention as a promising candidate for a hydrogen carrier. The present findings will significantly promote the development of the energy-saving processes of ammonia synthesis. Commonly, most of Ru catalysts are supported on metal oxides or carbon materials. In the present catalyst, flat-shaped Ru nanoparticles with a uniform size distribution are distinctly anchored on the surface of Ca(NH2)2 by strong Ru-N interaction. As a result, Ru-loaded Ca(NH2)2 exhibits high catalytic performance and long term stability for ammonia synthesis under low reaction temperatures.