The commented paper published in 2019 is the second paper to claim the successful synthesis of Ti2NTx MXene from Ti2AlN. The etching solution is HF. However, the X-ray diffraction (XRD) patterns of Ti2NTx MXene in the paper are completely different with that in the first paper in 2017 . Although the experiment in 2017 paper has not been repeated, the XRD pattern of Ti2NTx MXene in that paper was similar with those of other MXenes (Ti3C2Tx or Ti2CTx ). The feature of MXenes' XRD patterns is that there is a very strong (002) peak and other peaks are very weak. However, the XRD pattern in the commented paper is completely different with that in Ref. and does not have the feature of MXenes' patterns. In addition, it was acknowledged in the paper that the structure of Ti2NTx MXene was far from ideal. Moreover, in a recent work , it is theoretically indicated that Ti2NTx MXene cannot be successfully synthesized in HF solution from Ti2AlN, due to the fact that single layered nitride MXenes possess poor stability in the solution. Thus, we think that Ti2NTx MXene was not successfully synthesized in the commented paper.