Two-dimensional titanium carbonitrides and their hydroxylated derivatives: Structural, electronic properties and stability of MXenes Ti3C2−xNx(OH)2 from DFTB calculations

• Very recently 2D titanium carbonitrides have been synthesized.
• Structural, electronic properties and stability for these materials were evaluated.
• The hydroxylated derivatives of 2D titanium carbonitrides are examined.

The structural, electronic properties and stability of the new MXene compounds—two-dimensional pristine carbonitrides Ti3C2−xNx and their hydroxylated derivatives Ti3C2−xNx(OH)2 are studied by means of DFTB calculations. The genesis of the properties is discussed in the sequence: binary MXenes Ti3C2 (Ti3N2)→hydroxylated forms Ti3C2(OH)2 (Ti3N2(OH)2)→pristine MXene Ti3C2−xNx→hydroxylated Ti3C2−xNx(OH)2. All examined materials are metallic-like. The most favorable type of OH-covering is presented by the occupation of the hollow sites between three neighboring carbon (nitrogen) atoms. Two-dimensional MXene carbonitrides with random distribution of C and N atoms are found to be thermodynamically more favorable.

The side views of the optimized atomic structures of some examined hydroxylated derivatives of MXene Ti3CN and their electronic band structures.Figure optionsDownload as PowerPoint slide