Evaluation of 2D Tantalum Carbide MXene for Room to Mid-temperature Thermoelectric Applications

Tantalum carbide MXene (Ta₄C₃T_x) were synthesized via HF etching of the Al intermediate layer from the parental tantalum aluminium carbide MAX phase (Ta₄AlC₃). The structural and vibrational studies confirm the formation of MXene from the MAX phase without disturbing the hexagonal crystal structure. The synthesized samples were analysed using XRD to understand the phase structure. In and out of plane vibrational properties were examined by Raman spectrometer. XPS confirms the successful HF etching of Al in MXene phase and all other elemental configurations. HR-SEM and HR-TEM revile the exfoliated layered structure of the MXene and hexagon diffraction pattern of the tantalum carbide MXene sample with increased d-spacing. The TGA analysis demonstrated the thermal stability of the as-synthesized post measured compounds. The synthesized tantalum carbide MXene shows stable thermoelectric properties over six thermal cycles. The temperature dependent transport properties were measured from 303 K to 803 K. Ta₄C₃T_x MXene shows a maximum Seebeck coefficient of 13.8 μV/K and a power factor of 1.88 μW/mK² with the low lattice thermal conductivity of 5.42 W/mK at 803 K. In this present investigation, Tantalum carbide MXene demonstrated a decent thermoelectric property with high thermal cycling stability.