Oxide Carrier Ruthenium Catalyst For Ammonia Synthesis

The promoted Ruthenium catalysts are expected to be the second-generation Ammonia synthesis catalyst after the fused-iron catalysts. Therefore it has attracted much attention from both theoty and application study. In this article, catalysts supported on different Oxides were prepared and the effects of supports, promoters and the preparation conditions on the activity of ammonia synthesis were studied. It is found that the ammonia synthesis activity of Oxide supported Ruthenium catalyst is directly related to the basicity of Oxide, and the Al203 supported Ruthenium catalyst activity has no relation with the physical properties of support such as the BET surface area and the pore structure. But for MgO supported ruthenium catalyst, the activity increased when the BET surface area increased. It is found that the single promoter is even better than the double promoted catalyst for Oxide supported catalysts. Among the promoters used, i.e. alkali metal, alkali earth metal and rare earth metal, the Ba compound are found to be more effective than others. When the K were added to Ba-RuIMgO catalyst, the activities decreased. And the catalyst is more active when the promoter is impregnated after RuCI3/MgO is reduced than the promoter is impregnated before introducing RuCl3 or co-impregnation of promoter and precursor. The factors affected the preparation were considered too, and found that the concentration of precipitation impregnation affected the Magnesium Oxide supported Ruthenium catalyst greatly. And through the study of the impregnation pH and time on the catalyst activity, we found that RuCI3 and MgO have strong interactions, and this result was confirmed by TPR and TGA analysis Methods. In addition, the reduction during the preparation process were studied too, the best reduction temperature is 300 0C,and the ruthenium catalysts needn抰 to be activated before -In- 1< Abstract measuring the catalyst activity. Trough the studies on the preparation method, it is found that use vacuum filtration and washing with water before drying can remove Cl and increase the catalyst activity. At last the summarization of the whole dissention and prospect for the research on the Oxide supported Ruthenium Ammonia Synthesis catalysts are put for-ward.