Synthesis and Characterization of Two‐Dimensional Nb4C3 (MXene).

Phase-pure, two-dimensional Nb4C3Tx (Tx: general surface termination) is synthesized by immersion of Nb4AlC3 powder (obtained by in situ hot pressing of mixtures of the elements at 3 MPa and 1700 °C for 1 h) in 48-51% aqueous HF for 96 h at ambient temperature with stirring (77% yield).