By etching out the aluminum, the MAX phases were converted to MXenes. However, the Nb2CTx also has a significant amount of unreacted Nb2AlC, while NbC remains present as an impurity in Nb4C3Tx, as previously seen for other MAX/MXene samples. The 93 Nb NMR spectra of Nb2CTx and Nb4C3Tx are shown in Figure and Figure .