The Preparation And Properties Of Ceria/2-D Titanium Carbids Nanocomposites

In recent years,two-dimensional layered transition metal carbide MXenes,as a new layer material,has shown potential application in the field of environmental purification.Ti₃C₂,as the most widely investigated one,showing good potential in the adsorption and degradation of organic dyes.However,due to its relatively low surface area,the prepared organ-like Ti₃C₂ shows a general performance of organic dye degradation.As a semiconductor oxide,when CeO₂was used as photocatalyst,it shows good photocatalytic activity.But Ce O₂ can be easily agglomerate.In order to further improve the photocatalytic performance of Ti₃C₂ and CeO₂,this paper carries out the following research work.（1）The composition,morphology,adsorption and degradation performance of Ti₃C₂ and CeO₂ nanosheets/Ti₃C₂.The results show that Ti₃C₂ has unique 2-d layer structure,surface area is relatively small,only 6.9858 m²g^-1,terminated functional groups with hydroxyl,fluoride and oxygen.And Ti₃C₂ is negatively charged,thus it can adsorb positively charged ions.Then Ti₃C₂ has the ablity to absorb and degrade rhodamine B and methyl orange,and the adsorption of rhodamine B is better than methyl orange.And it always achieved adsorption equilibrium after 1 h.In addition,Ti₃C₂ showed photocatalytic performance for both dyes,and the photocatalytic degradation efficiency was basically no difference.The CeO₂ nanosheets/Ti₃C₂ nanocomposite was prepared by hydrothermal method and it ia applied to degradation of methyl orange dye under UV-light.The results showed that the efficiency of Ce O₂ nanosheets/Ti₃C₂ comoposite on the photocatalytic of methyl orange was better than single Ti₃C₂ and cerium oxide,the superior performance may attribute to the synergistic effect of the two materials.（2）In order to improve the photocatalytic properties of CeO₂ materials,the preparation of the cerium oxide nanorods loading on the surface of layered Ti₃C₂was using a one-step in situ hydrothermal synthesis.Results show that the CeO₂nanorods,which have smaller particle size,uniform morphology distributed on the surface and interlayer of Ti₃C₂.The photocatalytic properties of Ce O₂nanorods/Ti₃C₂ have a significant increase of methyl orange compared with Ti₃C₂and pure cerium oxide.After the photocatalytic degradation of 20 mg/l rhodamine B in the experiment,the photocatalytic decolorization rate of Ce O₂nanorods/Ti₃C₂ reached 75%after 90 min’s uv irradiation.The improved performance is due to the synergistic effect between CeO₂ and Ti₃C₂.（3）In order to prepare the different morphology of CeO₂/Ti₃C₂ composite material,the preparation of the cerium oxide nanowires loading on the surface of layered Ti₃C₂ was using a one-step in situ hydrothermal synthesis,as well as study its formation mechanism.The results showed that the growth of cerium oxide on the surface of the load on Ti₃C₂ follow the"directional attachment"mechanism,mainly along the（211）crystal plane of cerium oxide growth,when adding different cerium ion molar mass,it respectively showed different morphology,ratio of cerium oxide and titanium carbide has a great influence on the morphology of CeO₂ nanowires/Ti₃C₂ composite.（4）For further improve the photocatalytic performance of CeO₂ materials,the CeO₂/Ti₃C₂ nanocomposite was prepared by simple precipitation method.The results show that the smaller particle size,morphology of CeO₂ nanoparticles successfully load on 2-D stratified Ti₃C₂ substrate surface and the interlayer.The decoloring performance of CeO₂/Ti₃C₂ have a significant increase of methyl orange,which respectively compared with Ti₃C₂ and pure cerium oxide.In test,when 5 ml of cerium solution was added to composite material,the decolorization rate was 76%in the concentration of 20 mg/L of the decolorization of methyl orange solution experiment,the dark conditions continue to 60 min after reaction,solution absorbance was almost zero,the color of the solution with a yellow to colorless.when 30 ml of cerium solution was added to composite material,for concentration of methyl orange solution for 50mg/L decoloring performance,the composite-30 was not only better than Ti₃C₂and pure cerium oxide,also better than that of other composite material proportion and after 5 min’s ultrasound,the decolorization rate was 45%,the dark conditions continue to 60 min after reaction,decoloring rate can reach 75%.The excellent decolorization performance of the CeO₂-Ti₃C₂ nanocomposite was due to the synergistic effect of the matrix Ti₃C₂ and CeO₂ nanoparticles.