Research On Preparation Of Ni₂P@MOFs Composite And Its Characteristic

At present,electromagnetic wave has been applied more and more widely in electronic communication,medical treatment,transportation and other high-tech industries,which makes the energy density generated by electromagnetic wave in our living space increase continuously.Excessive electromagnetic wave radiation will harm human health,so absorbing materials begin to be favored by researchers.Electromagnetic wave absorbing materials are also high and new technologies that national defense and military pay attention to,so the research of thin thickness,light weight and high bandwidth absorbing materials has been continuing.In this paper,Materials Studio simulation software is used to compare the electronic structure and optical properties of two typical phosphide compounds Ni₁₂P₅ and Ni₂P from the microscopic field.With the simulation results as guidance,Ni₂P materials with better optical properties are screened out and prepared for research.And composite Ni₂P with metal organic frameworks（MOFs）to explore and design high-performance electromagnetic wave absorbing materials.The specific research content is as follows:（1）Firstly,the electronic structure and optical properties of Ni₁₂P₅ and Ni₂P were studied using Materials Studio software according to first principles of density functional.The electron bond properties are analyzed by means of electron localization function and electron density difference,and the optical properties are evaluated by calculating complex dielectric spectrum.The results show that Ni₂P has higher absorptivity and lower reflectance,which provides a theoretical basis for subsequent preparation and performance research.（2）Phosphate compounds were prepared using triphenylphosphine and nickel acetylacetone as raw materials by solvothermal method.Ni₂P and Ni₁₂P₅ were prepared by adjusting the reaction temperature,reaction time,and reactant ratio,respectively.And analysis and characterization were conducted.The experimental results indicate that the optimal conditions for preparing Ni₂P are reaction temperature of 200℃,reaction time of 24 hours,and P:Ni ratio of 5.Compared with Ni₁₂P₅,Ni₂P nanoparticles have uniform dispersion,uniform morphology,smaller particle size and about 10nm in diameter,which is more suitable for composite with MOFs materials.Ni-MOF precursors were prepared using benzoic acid,triethylenediamine,and nickel sulfate as raw materials by solvothermal method.The smooth surface of Ni-MOF was observed to be rectangular by scanning electron microscopy.Ni₂P is added into the raw material for preparing Ni-MOF,keeping the preparation conditions of Ni-MOF unchanged,so that it can adsorb Ni₂P nanoparticles to prepare Ni₂P@MOFs Composite materials.（3）The ultraviolet,magnetic and wave-absorbing properties of the materials were tested.The UV test results show that the Ni-P bond in Ni₂P is stronger than that in Ni₁₂P₅,which is consistent with the calculation results of band structure,indicating that the simulation results are reliable.Ni₂P@MOFs has high absorption values in both ultraviolet and visible regions.The magnetic test results show that with the addition of Ni₂P,the saturation magnetization（Ms）of Ni₂P@MOFs composite is larger than that of Ni-MOF material,thus increasing the electromagnetic loss capacity.The test results of absorption performance indicate that Ni₂P@MOFs Compared with Ni-MOF materials,composite materials have improved their dielectric loss and electromagnetic loss capabilities.Compared to a single Ni₂P material,they have optimized impedance matching characteristics and increased their effective absorption bandwidth.So the overall absorption performance of composite materials is better.Ni₂P@MOFs has a minimum reflection loss of-27 d B at 10.5 GHz,the corresponding thickness is 2.5mm,and the effective bandwidth is 6 GHz.It is a kind of excellent absorbing material.