Multilayered MXene powder was collected by filtration through a cellulose acetate membrane (0.45 µm pore size). The delamination of Nb2CTx was carried out by transferring 1.0 g of MXene powder into 10 mL of a diluted tetramethylammonium hydroxide (TMAOH) solution (25% in H2O, Millipore-Sigma). The solution was stirred overnight (~18 h) at room temperature. To remove excess TMAOH, the mixture was washed by centrifugation with DI water (50 mL) at 3500 rpm for 20 min followed by decantation of the supernatant. The process was repeated until the supernatant reached a pH <8. Then, the sediment was dispersed in 50 mL of deionized water and sonicated for 1 h in an ice-bath with Ar bubbling. Finally, the mixture was centrifuged for 1 h at 3500 rpm, and the supernatant was carefully removed to leave the MXene sediment in the bottom of the tube.