Effect Of Nitrogen-Doping On Hydrogenation Performance Of Carbon Supported Ruthenium Catalyst

Ruthenium-carbon catalysts have excellent catalytic performance in small molecule catalytic hydrogenation reactions such as nitrogen(ammonia synthesis),CO(Fischer-Tropsch synthesis)and liquid phase hydrogenation reactions of some fine chemicals.Nitrogen doping is a universally effective measure to further improve the performance of ruthenium-carbon catalyst.In this paper,the effect of nitrogen doping on the performance of ruthenium-carbon catalyst was studied,and the preparation and performance of nitrogen-doped mesoporous ruthenium-carbon catalyst prepared by in-situ nitrogen doping one-step method were also studied.The main results are as follows:1.The effect of nitrogen doping on the supported ruthenium-carbon catalyst and its hydrogenation performance was studied.Activated carbon was modified with nitrogen by post-treatment doping method,and supported ruthenium-carbon catalyst was prepared on the modified carbon.The catalytic activity of the nitrogen-doped catalyst Ru/NAC in benzene ring hydrogenation reaction with different substituents was better than that of Ru/AC.The introduction of nitrogen improves the metal dispersion and Ru electron density of the catalyst.2.The effect of nitrogen doping on the structure and hydrogenation performance of mosaic ruthenium-carbon catalyst was studied.On the basis of the original preparation method of mosaic catalyst,nitrogen doped mosaic ruthenium-carbon catalyst Ru-NMC was synthesized in situ by mixing nitrogen source with other precursors,and catalysts with different nitrogen contents were prepared by adjusting the addition amount of nitrogen source.The benzoic acid hydrogenation activity of Ru-NMC is obviously lower than that of Ru-MC,and the higher the nitrogen content,the lower the catalytic activity.Although nitrogen doping retains the mesoporous structure of the original Ru-MC,the specific surface area and pore volume and other parameters decrease to some extent.Due to the simultaneous doping of nitrogen and ruthenium in the preparation process,the nitrogen skeleton and ruthenium are respectively embedded on the carbon skeleton,leading to the effect on the catalyst different from that of the supported type.3.Lime nitrogen derived carbon material MGC was prepared by using wheat flour as carbon source and lime nitrogen as template agent.The original carbon of lime nitrogen,which is mainly graphite structure,can be used as "growth core" in the carbonization growth process,and derived carbon similar to graphite structure is grown on its peripheral edges.Calcium cyanamide,the main component of lime nitrogen,can provide abundant nitrogen sources.Therefore,MGC is a new nitrogen-doped carbon material containing graphite structure,and ruthenium catalyst supported by MGC shows excellent catalytic performance in aniline hydrogenation.