  In the present work, the three stable MXenes M n+1 C n O 2 (M=Nb,Ta) are
explored based onfirst-principles calculations. These materials are important
derivatives of 2D materials and exhib-it distinctive properties, holding vast
potential in nanodevices. All these M n+1 C n O 2 (M=Nb,Ta)materials exhibit
outstanding superconducting performance, with corresponding
superconductingtransition temperatures of 23.00K, 25.00K, and 29.00K. Analysis
reveals that the high supercon-ducting transition temperatures of MXenes M n+1
C n O 2 (M=Nb,Ta) are closely associated with thehigh value of the logarithmic
average of phonon frequencies, {\omega} log , and the strong
electron-phononcoupling (EPC), attributed to the crucial contribution of
low-frequency phonons. Additionally, weapplied strain treatments of 2% and 4%
to M n+1 C n O 2 (M=Nb,Ta), resulting in varying changes insuperconducting
transition temperatures under different strains.
