Preparation And Properties Of Composite Functional Materials Based On Carbon Nanotubes

Due to the large specific surface area and large pore volume of carbon nanotubes?CNTs?,the material has been tried in many fields such as adsorption,hydrogen storage,lithium storage,catalysis.Based on the preliminary work of the research group,the hydroxylated multi-walled carbon nanotube materials were esterified with bisphosphonic acid?HEDP?and triphosphonic acid?ATMP?to obtain two kinds of materials?HEDP-MWCNTs,ATMP-MWCNTs?and the adsorption properties of HEDP-MWCNTs and ATMP-MWCNTs for Hg???were tested.After depositing Fe₃O₄on the outer layer of CNTs,CNTs@Fe₃O₄ was obtained then ATMP was grafted to the outer layer of CNTs@Fe₃O₄ to obtain magnetically acid catalytic material?CNTs@Fe₃O₄-ATMP?and the acid catalysis performance of this material was tested.The above-mentioned HEDP-MWCNTs were loaded with barium sulfide to obtain a hydrogen storage material?HEDP-CNTs@sulfurium sulfide?and the properties of the material for electrochemical storage of hydrogen were explored.A series of characterizations such as FT-IR,SEM,XRD and TG were performed on the various materials prepared above.The main content of this paper is divided into the following parts:1 The bisphosphonated carbon nanotubes?HEDP-MWCNTs?were prepared by MWCNTs as the matrix and modified by phosphinic acid?HEDP?.The adsorption properties of HEDP-MWCNTs for Hg???were investigated in detail.It is found that the adsorption effect of Hg???is relatively good when the pH value of the solution is in the range of 4.0-5.0.The adsorption amount of Hg???can reach 1.5mmol/g.The dynamics adsorption data of HEDP-MWCNTs to Hg???is in agreement with the second-order kinetic equation.The rate control step of the adsorption process is a step in which Hg???diffuses to the surface of HEDP-MWCNTs.This process belongs to the heat absorption that can occur automatically with Hg???chaos.The isothermal adsorption reaction of HEPD-MWCNTs to Hg???data can better match the Langmuir model.HEDP-MWCNTs have better recognition and adsorption property of Hg???.After two cycles of use,the elution rate can still keep above 70%.2 The trisphosphonated carbon nanotubes?ATMP-MWCNTs?were prepared by esterification of MWCNTs with phosphonate?ATMP?.The adsorption behavior of ATMP-MWCNTs on Hg???was investigated in detail.It can be seen that the optimum adsorption performance of ATMP-MWCNTs for Hg???is 200mg/g when pH is 5.0.The data of dynamic adsorption of Hg???by ATMP-MWCNTs is more consistent with the second-order kinetic equation.The rate controlling step of the adsorption process is a step in which Hg???diffuses to the surface of the ATMP-MWCNTs.The process automatically generated belongs to the heat absorbing reaction in which the Hg???chaos.The isothermal adsorption data can be well matched with the Langmuir model.the material has good recognition and adsorption property for Hg???.3 After depositing Fe₃O₄ on the outer layer of CNTs,CNTs@Fe₃O₄ was obtained.The triphosphonic acid?ATMP?was grafted to the outer layer of CNTs@Fe₃O₄ to obtain acid catalytic material?CNTs@Fe₃O₄-ATMP?and it's acid catalytic property was discussed.The esterification experiment showed that the catalytic effect of the product prepared by the reaction of CNTs@Fe₃O₄ and phosphinic acid?ATMP?at a mass ratio of 1:4 was relatively good.in the range of 60-90°C.The higher the temperature,the better the catalytic effect.The oleic acid conversion rate can reach90%at 90°C.The catalytic esterification data is more consistent with the reversible second-order kinetics.The activation energy of the positive reaction is 24.1 kJ×mol^-1.4 Hydrogen storage materials?HEDP-CNTs@sulfurium sulfide?were prepared by combining HEDP-MWCNTs with barium sulfide by precipitation method and HEDP-CNTs@sulfurium sulfide was used as an electrode active material to explore its hydrogen storage performance.The constant current charging-discharging experiments show that HEDP-CNTs@sulphide has a relatively high hydrogen storage capacity?up to 260 mA×h/g?.Cyclic hydrogen storage experiments show that HEDP-CNTs@strontium sulfide has better performance in circulating hydrogen storage.Cyclic voltammetry experiments show that the discharge potential peak of the material is located at-0.3V vs?Hg/HgO?.Impedance experiments show that the charge can be transferred rapidly at the interface between the electrode and the solution and the interface resistance is small.