Preparation Of Cobalt Manganese Heterogeneous Catalyst And Its Application In Aromatic Compounds Catalysis

In recent years,the research of catalytic reaction has become more and more in-depth,and highly efficient catalysts emerge in an endless stream,especially heterogeneous catalysts.Heterogeneous catalysts have not only solved the difficult problems of the recycling,but also overcame the world problems of precious metals loss and heavy metal pollution.The choice of carrier materials has great influence on catalytic reaction in heterogeneous catalysts.Based on this,two transition metal heterogeneous catalysts supported by porous materials were designed,and then applied to the oxidation and reduction of organic compounds.A facile method to synthesize nitrogen-doped reduced graphene oxide supported cobalt based catalyst through a one-step pyrolysis of phenanthroline chelated and graphene oxide dispersed cobalt nitrate were reported.The as-prepared catalyst exhibited excellent catalytic performance in hydrogenation of p-nitrotoluene(both conversion rate and selectivity exceed 99%)with high turnover frequency(TOF,ca.101.6 h-1)under mild conditions(120 ?,2.0 MPa initial H2 pressure and 3 h),and remained the initial efficiency after five cycles.The synergistic effects were revealed by a series of characterizations and control experiments.The unique structure of reduced graphene oxide encapsulated metallic cobalt and the electronic activation of quaternary nitrogen formed by cobalt catalysis during the pyrolysis endow the high catalytic performance,durability,and specifity.In addition to the reduction reaction catalyst,we also synthesized a manganese based catalyst with nitrogen doped alumina with the similar synthesis method by using phenanthroline as nitrogenous ligand.It is proved that the nitrogen doped alumina supported manganese has excellent catalytic activity and good stability.It is an excellent catalyst for selective oxidation of ethylbenzene by molecular oxygen.Meanwhile,we have proved that phenanthroline can help to lock more manganese,and divalence manganese together with pyrrole-type N promote the oxidation of ethylbenzene.In the process of oxidation,divalence manganese is the main active component of the catalytic reaction.The active components in the bulk phase are more,which ensures the stability and reusability of the catalyst.