Fig. 1: Characterization of Mo₂CT_x and its reduction to 2D-Mo₂C.

a Schematic of the preparation of 2D-Mo₂C from Mo₂CT_x. b ⁹⁵Mo VOCS CPMG MAS NMR spectrum of Mo₂CT_x. c Temperature-programmed reduction of Mo₂CT_x in pure H₂. d Reduction of Mo₂CT_x followed by in situ Raman spectroscopy with a final isothermal heating step at 500 °C performed for 2 h (see Supplementary Fig. 8 for the stacked Raman spectra). e Reduction of Mo₂CT_x followed by in situ XRD (the peaks of β-Mo₂C are marked by asterisks and the main reflections of Mo₂CT_x are indexed, see Supplementary Fig. 9 for the 3D plot). f Mo 3d XPS spectra (see Supplementary Table 1 for the fitting parameters). g Mo K-edge XANES spectra of Mo₂CT_x, 2D-Mo₂C, and reference β-Mo₂C. h CO temperature-programmed desorption (TPD) of 2D-Mo₂C and β-Mo₂C.