CO₂ Adsorption Of Metal Doped MIL-125（Ti） And Properties Of Supercapacitor Electrode Materials

With the development of society and the advancement of science,the demand for energy by human beings is increasing,and the drawbacks caused by the consumption of traditional fossil energy are increasingly prominent.CO₂ causes the greenhouse effect and has already threatened the living environment of human beings.Therefore,research on new porous materials is particularly critical.As one of the new porous materials,Metal Organic Frameworks（MOFs）have broad application prospects in gas storage,biosensing,photocatalysis and electrochemistry.The functional modification of MOFs can further improve its performance and therefore has important research value.In this paper,the Ti-based MOF material MIL-125（Ti）was used as the research object,and the effects of metal doping method and content on its CO₂ adsorption and supercapacitor electrode material properties were discussed:M@MIL-125（Ti）-n and M@NH₂-MIL-125（Ti）-n were prepared by post-impregnation method（M represents alkali metals:Li,Na and K,respectively;n represents immersion time:6 h,9 h and 12 h,respectively）.It was found that the valence bond structure and phase of the composite obtained under different immersion times did not change significantly,indicating that the post-impregnation doping did not change the structure of the MOFs.The difference in the type of alkali metal ion doping makes the thermal stability of the material slightly different.The CO₂ adsorption test results show that the CO₂ adsorption performance of the composites after alkali metal doping is improved,among which Na@MIL-125（Ti）-9 and Na@NH₂-MIL-125（Ti）-9 are at 293K,1 The amount of CO₂ at atm conditions reached 1.41mmol/g and 2.30 mmol/g,respectively.Alkali-doped xM@NH₂-MIL-125（Ti）was prepared by hydrothermal in-situ synthesis doping（M is consistent with the above;x represents mass doping percentage:1 wt%,2 wt%,respectively）.The SEM results show that the concentration of doped metal ion will affect the growth rate of titanium ions and organic ligands.The composites show discs,squares and truncated octahedrons.The CO₂ adsorption test results show that the CO₂ adsorption performance of the composites obtained by hydrothermal in-situ synthesis of alkali metal is obviously improved.The amount of CO₂ in 1Li@NH₂-MIL-125（Ti）-9 at 293K,1 atm is respectively It reached 4.65 mmol/g.Nickel ion-doped yNi@MOF and Ni@MIL-125（Ti）-y were synthesized by solvothermal method(y represents the molar multiple of Ni²⁺to terephthalic acid:1,2 and 3,respectively),and their properties as supercapacitor electrode materials were investigated.The bonding mode,phase and thermal stability of the samples were characterized by FT-IR,XRD and TG.The electrochemical performance was tested by cyclic voltammetry,chronopotentiometry and alternating current impedance.The results show that the window voltage of Ni@MIL-125（Ti）-3 is 0.05-0.5 V and the specific capacitance is 1100 F/g at 1 A/g.