Study On Preparation And Properties Of Novel 35P-MOFs/Carbon-based Materials

Metal Organic Frameworks?MOFs?are relatively new regular crystal structures assembled from metal ions and organic ligands in the field of materials.Because of its infinite network topology with various structures and controllable morphology,it has shown attractive application prospects in the fields of chemical catalysis,electrochemistry and biomedicine.Considering coordination polymers and their composites have rarely been discussed in depth as electromagnetic wave absorbing materials,the main research contents of this paper are as follows:?1?MOFs with 3,5-pyrazole dicarboxylic acid as the ligand and transition metals?Fe and/or Mn?as the central ions were successfully synthesized by hydrothermal synthesis and solvothermal synthesis,the products were labeled as 35PFe and 35PFeMn.The structure,morphology and composition of the MOFs were analyzed,and the microwave absorption properties of the samples were studied.The test results show that 35PFeMn has certain electromagnetic wave absorbing properties and show unique absorbing features.?2?Study on composite modification of 35PFeMn and two types of carbon materials,respectively.One was to add different amounts of multi-layer graphene raw materials to the solvothermal reactions,the products are referred to as 35PFeMn/G-5 and 35PFeMn/G-10,respectively;the second was to use recycled biomass?pomelo peel?as a carbon source.The biochar material produced by calcination was added to the reaction,and the product was named as 35PFeMn/PPC.It was found in the electron microscope observation that MOF produced more layered morphology after compounding.The results show that 35PFeMn/G-10 has excellent microwave absorption performance.The material achieves maximum absorption at a frequency of 14.1 GHz and a matching thickness of only 1.5 mm,the optimal RL value can reach-34.47 dB and the effective bandwidth is 3.58 GHz?12.59-16.17 GHz?.?3?35P-MOFs/carbon-based derivatives were obtained by calcining 35PFeMn/G at high temperature.It was found that different types of iron-manganese oxides were obtained in different gas atmospheres.Samples of mixed oxides of Mn₃O₄ and Fe₂O₃ were obtained in an air atmosphere at 700?,MnFe₂O₄/G-5 and MnFe₂O₄/G-10 samples were obtained in a vacuum environment at 700?.From the results of the absorption,it can be seen that35PFeMn/carbon-based derivatives are all effective electromagnetic wave absorption materials;and among them,35PFeMn/G-10 derivative composite material MnFe2O4/G-10 shows a maximum reflection loss?RL?of-30.26 dB,with the thickness of 2 mm at a frequency of 11.5GHz.