Systhesis Of Carbon Supported Iron Nanomaterials And Their Application In Organic Reactions

Catalysts are the key elements of chemical reactions,which are required to be more qualified by the idea of green chemistry,including priorities such as economy,efficiency,environmental friendness and chemical stability.Precious metal has been serving as major commercial consideration in chemical process because of its high reactivity.However,its scarcity and low toxty-resistense makes production process complex and raising price in product.Therefore,development in nonnoble metal-based catalyst has attracting increasing attention.Since the discovery of fullerene,carbon materials have been intensively studied.Furthermore,nitrogen doping is an effective and simple method for modifying graphene.Besides iron as one of the most abundant elements of this planet process advantages of inexpensiveness and eco-friendness.Combining these three elements could compensate each other.The large surface area could be used to help stable and disperse the iron which could subsequently serve as catalytic center and catalytically promoted.Therefore,in this thesis we prepare two catalysts with carbon,nitrogen and iron,which are further deployed in organic reactions.The main contents are as follows:1.Via on-pot hydrothermal method,we prepared nitrogen doped graphene?NG?supported Fe₂O₃ composite catalyst with graphene oxide as raw material,urea as nitrogen source and FeCl₃ as iron source.In the oxidation of aromatic aldehyde,we have found that both NG and Fe₂O₃ have adsorption effect on O₂,and the adsorption effect on NG is relatively stronger.There are three types of nitrogen in the NG support,among which the pyrrolic nitrogen shows the strongest synergistic effect with Fe₂O₃.This type of cooperation could promote the crack of O-O bond and therefore enhance the catalytic reactivity of material.The prepared catalyst has shown a good tolerance over a variety of aromatic aldehyde derivatives and recycled for six times without dramatic reactivity deterioration.2.We have prepared an atomly dispersed Fe-N-C catalyst via high-temperature pyrolysis method with porous MgO as template.Confirmed by HAADF-STEM images,Fe atoms are stabilized by N atoms and uniformly dispersed in porous carbon in forms of FeNx.The chemical environment of Fe changes with temperature of catalyst synthesis.The EXAFS test shows that sample Fe-N-C-800 process the highest coordination number and therefore got a higher valance state.This contribute to the higher reactivity of Fe-N-C-800.In the application of dehydrogenation reaction of 1,2,3,4-tetrahydroquinoline,the reaction can occur at lower temperature under O₂ atmosphere.The as prepared catalyst shows decent reactivity comparable to noble metal catalysts.The catalyst could be recycled for five time and still shows satisfying reactivity.The above experimental results provide a new way of application of carbocatalyst Besides we have increased our recognition of catalysis system with iron,nitrogen and carbon.Proved that carbocatalyst are promising candidate for substituting noble based support catalyst.