Ruthenium Catalyst Supported On Alumina For Ammonia Synthesis

The promoted Ruthenium-based catalysts for ammonia synthesis are expected to be the second-generation catalysts for ammonia synthesis. Much more attentions to the studies of Ru-based catalysts both in theory and application have been extensively attracted. In this thesis, effects of preparation conditions, promoters and alkaline earth metallic oxides modification for support on the catalytic activity of ruthenium supported on alumina for ammonia synthesis are studied.The catalytic activity increased with the increase of the calcination temperature of aluminum hydroxide, and the highest activity was obtained at 800 癈 . Furthermore, the basicity increased with the increase the calcinations temperature too, while the specific surface area decrease. These results indicated that the catalytic activity is primarily dependent on the surface basicity of support, while not significantly dependent on the specific surface area of support.The result on the effect of reduction temperature indicated that the reduction temperature influences slightly the catalytic activity of Ba-Ru-K/AbOs catalyst.The presence of promoter K, Ba and Sm increase the catalytic activity of Ru/AhOa, and the catalysts promoted with bi-promoters show a higher activity than that promoted by single one. The promoters play different roles in the weakening hydrogen adsorption on Ru sites. The activity of catalyst promoted with Sm, Ba increase with the increase of pressure, but the activity of catalyst promoted with K does not.The modification with alkali earth metallic oxides for alumina will improve the catalytic activity of Ru/A^Os for ammonia synthesis. The modification of alkali earth metallic oxides was found to be a good method to increase the catalytic activity of Ru/Al2O3 for ammonia synthesis. It was found that the catalytic activity of Ru/Al2O3 was markedly increased with the enhancement of the surface basicity of the modified support, though the specific surface areas of these supports were deduced.In addition, the effect of promoter on activity of alumina modified with alkaline metallic oxides supported ruthenium catalyst has been studied. The results indicated that the effects of promoters are dependent on alkaline metallic oxides, using for modification of alumina. On the whole, Ba-K, and Ba are available promoters for ruthenium catalyst supported on alumina modified with alkali earth metallic oxides.