Synthesis And Microwave Absorption Properties Of MOF Derived Co/C-doped Graphene

The metal-organic framework has been applied to the research of wave-absorbing materials due to its special physical and chemical properties.The composite materials with metal ions and organic ligands as precursors have also been proven to have good wave-absorbing properties.Most of the existing metal-organic ligands have good magnetic loss capability.In order to enhance the ability of the material to absorb electromagnetic waves,it is often combined with a dielectric material having excellent dielectric loss capability.Based on this,this paper uses hydrothermal synthesis of metal-organic framework as a precursor,and on this basis,it is compounded with graphene oxide to prepare higher performance wave absorbing materials.The main research contents are as follows:(1)Synthesize and characterize cobalt ion and dimethylimidazole as metal-organic framework precursors.The morphological characterization by TEM and SEM shows that the prepared material has a microsphere structure;the structural characterization by XRD and Raman shows that the element composition and crystal structure of the synthesized product are Co/C materials.(2)The reaction dosage ratios of cobalt nitrate and dimethylimidazole were 1:1,1:2,1:3,and 1:4 respectively,and the optimal dosage ratio of the two with the most excellent wave absorption performance was determined.The experimental results show that when the dosage ratio of cobalt nitrate to dimethylimidazole is 1:3,cobalt ions can fully react with organic matter,at which time the material has the best wave-absorbing performance,The reflection loss after annealing is-10.115 d B at d=1 mm.(3)Co/C/reduced graphene oxide composite material is prepared by physically mixing the metal-organic framework precursor synthesized with cobalt ion and dimethylimidazole and graphene oxide.After adding 5mg / ml of graphene oxide,the aggregation of the metal-organic framework is effectively prevented,so that it can be uniformly attached to the graphene oxide.Compared with before graphene oxide is not added,the reflection loss value of the material is reduced.When d=1.5 mm,its reflection loss value reached-11.372 GHz.This shows that the addition of graphene oxide effectively improves the microwave absorption performance of the composite material.(4)Explore the influence of the amount of graphene oxide in the composite material on the wave absorption performance of the material.Compare and analyze thedoping ratio of graphene oxide in the composite material to 0%,2%,4%,6%,and 8%.The best doping concentration of graphene oxide.The experiment proves that when the doping mass ratio of graphene oxide is 6%,the reflection loss of the composite material reaches the optimal value.At the electromagnetic wave frequency of 15.62 GHz and d =1.5 mm,the reflection loss reaches-25.182 d B,the bandwidth less than-10 d B is 5.36 GHz.Figure 24,table 4,references 56.