Study On Preparation And Etching Process Of Magnetic Elements Doped MAX

Two-dimensional materials have become one of the hottest frontiers in the material fields based on its unique structure,excellent physicochemical properties and extensive application,meanwile,they have received the attention from researchers around the world.MXene joined the extended family of two dimensional materials in 2011.As a member of two dimensional materials,MXene has been compared with graphere since its inception.MXene has become the center of research in the fields of energy storage,adsorption,catalysis,composite and so on based on its unique microscopic structure,excellent electrical and thermal conductivity,and variable surface functional groups.The sintering process of Ti₃AlC₂ and Ti₂AlC will be studied in the paper.The MAX is changed into two-dimensional MXene by HF and in-situ etching with hydrochloric acid and LiF.The structure and properties of the MXene are analyzed and characterized.The shielding effectiveness of Ti₃C₂T_x doped with Fe are analyzed.Ti₂AlC and Ti₃AlC₂ that is the precursor of MXene are prepared by pressureless sintering with high temperature using Ti,Al and C as raw materials.The effects of Al/C ratio,sintering temperature and additive Si in the initial reactants on the purity of the final product are systematically studied.The reaction mechanism and the mechanism of carbide formation are analyzed,and the best synthesis conditions are established.Ti₃AlC₂ was doped with Fe and Mn.The phase composition of the product after doping is characterized by XRD,and its magnetic property is characterized.Two-dimensional-material MXene is prepare by HF and hydrochloric acid with LiF.The microstructure and crystal structure of Fe-doped Ti₃C₂T_x are studied by means of XRD,scanning electron microscopy,transmission electron microscopy,XPS and Raman.It is found that Fe-doped Ti₃C₂T_x retains the same hexagonal structure as its precursor,and attached functional groups such as-OH,-F,-O on its surface.The product retains accordion structure with the HF etch.The layers are more clear and the sheets are more complete with situ etching.The thermal stability of Fe-doped Ti₃C₂T_x is analyzed in nitrogen atmosphere.It is found that H2O and-OH attaching on the surface of MXene could be removed under heating conditions.The shielding effectiveness of Fe-doped Ti₃C₂T_x were tested by vector network analyzer.It is found that the shielding effectiveness of Ti₃C₂T_x significantly improve with doped 2.5%Fe.When the amount of Fe is too much,the shielding efficienctiveness decreases.Maybe the number of defects of MAX will increase afer the excessive amount of Fe is doped,which leads to the crushing of the finally synthesized sheets resulting in affecting the shielding effectiveness.