Fig. 2

a Schematic diagram of the preparation process of Ti₃AlC_2. Reproduced with permission from Ref. [14], © American Chemical Society 2017. b Symmetric 2θ X-ray diffractograms of Mo₂Ga₂C film before and after HF etching. Reproduced with permission from Ref. [25], © Elsevier 2015. c A higher magnification TEM micrograph of a Mo₂Ga₂C thin film after etching in 50% HF (aq). Reproduced with permission from Ref. [25], © Elsevier 2015. d SEM images of the 2D Zr₃Al₃C₅ after HF treatment. Reproduced with permission from Ref. [26], © Elsevier 2020. e X-ray diffractograms of YAl₃C₃ before and after HF treatment. Reproduced with permission from Ref. [26], © Elsevier 2020