Energy Band Regulation And Photocatalytic Performance Of Two-dimensional Ti₃C₂T_x Composites Semiconductor Materials

MXene was used in catalysis,adsorption,stored energy and other fields,due to its unique two-dimensional layered structure,large specific surface area,excellent electrical conductivity and higher thermal stability.In this paper,Ti₃AlC₂ ceramics were obtained by self-propagating high-temperature synthesis.The two-dimensional layered powders of Ti₃C₂T_X?T=OH,F or O?were obtained by chemical etching.The energy band regulation and photocatalytic degradation properties of Ti₃C₂T_X composites were researched.The following main conclusions were obtained:1.Ti₃AlC₂ ceramics were prepared by self-propagating high-temperature synthesis method using Ti,Al,C and TiC powders as raw materials.The effect of TiC and Al content on the content of Ti₃AlC₂ was researched by changing with different molar ratio of synthetic raw materials.The optimum molar ratio was n?Ti??n?Al??n?C??n?TiC?=2?1.7?1?0.9.2.The etching degree of the Al atomic layer in the Ti₃AlC₂ powder.Under the room temperature and 60 ^oC,the etching effect on the Al atom layer becomes more obvious with the etching temperature increasing.The stratification effect of Ti₃C₂T_X obtained by etching Ti₃AlC₂ powder for 20 h was better at 60 ^oC.3.TiO₂/Ti₃C₂T_X composites were synthesized by solvent thermal method,the morphology of composites were synthesized by using different agents such as deionized water?H₂O?,ethanol?C₂H₆O?and isopropanol?C₃H₈O?.The composites used C₃H₈O agent showed the highest activity,which the removal efficiency of methyl orange?MO?reached 90.5%after 75 min under mercury light irradiation,and the photodegradation rate up to 89.7%after 240 min under xenon light illumination.4.The uniform growth of TiO₂ nanoparticles on the layered structure of Ti₃C₂T_X was optimized by changing the solvothermal reaction time.The results showed that the TiO₂/Ti₃C₂T_X-36h composites exhibited a degradation rate of 0.0039 min^-1 with in 75min under mercury light irradiation,and the MO removal efficiency reached around92.7%.Degradation rate amount about 0.0091 min^-1 was observed after 240 min under xenon light illumination for the TiO₂/Ti₃C₂T_X-24h composites,meanwhile,the MO removal efficiency reached around 89.7%.5.The exposed crystal surface TiO₂/Ti₃C₂T_X composites were prepared by changing the addition amount of NaBF₄ and reaction temperature.The results showed that the removal rate of MO in TiO₂/Ti₃C₂T_X-200^oC was 92.0%under mercury light after 50 min,and the removal rate of MO under xenon light was about 90.0% after 120min.