超声辅助刻蚀对Ti_3C_2T_x微观结构的影响

Effect of Ultrasonic Assisted Etching on Microstructure of Ti_3C_2T_x

二维层状材料MXene由于其独特的物理化学性质,受到了广泛关注。本文通过超声辅助刻蚀Ti_3AlC_2的方法制备了多层的Ti_3C_2T_x,利用X射线衍射仪、N_2吸脱附测试、扫描电子显微镜和透射电子显微镜对其微观结构的变化特征进行了详细的表征和分析,并与磁力搅拌刻蚀制备的Ti_3C_2T_x样品相对比。结果表明,与磁力搅拌刻蚀相比,超声辅助刻蚀可以进一步减小Ti_3C_2T_x平均薄层厚度和增加原子层间距,主要原因是超声处理能够促进未发生反应的薄片层中Al原子层的刻蚀。刻蚀过程中同一Al原子层有些区域先发生刻蚀,而一些区域依然存在Al原子。探明了附着在Ti_3C_2T_x表面几十纳米的颗粒是空间群为■的六方结构AlF_3,并且随着刻蚀时间的增加,其逐渐向非晶体转变。

Two-dimensional MXenes attract great interest due to their unique physical and chemical properties. Ti3C2Tx MXene is synthesized by ultrasonic assisted etching. The resulted microstructures are characterized and compared with those Ti3C2Tx samples synthesized via magnetically stirring etching,by X-ray diffractometer, N2 adsorption and desorption, scanning electron microscope(SEM) and transmission electron microscope(TEM). The results demonstrate that ultrasonic assisted etching can further reduce the lamellar thickness of Ti3C2Tx and increase the atomic layer spacing,comparing with the method of magnetically stirring etching. A gradual dissolution is observed in the same Al atomic layers during etching. The particles with several tens of nanometers in size are frequently formed in contact with the surface of Ti3C2Tx. These nano-particles are determined to be hexagonal AlF3 with space group of R3. A gradual change from crystalline form to amorphous structure is also detected for hexagonal AlF3 with prolonged etching time.