fig1

Figure 1. First-principles design of 2D-Fe₃C₁₈. (A) Schematic illustration of the 2D-Fe₃C₁₈ construction process, achieved by integrating Fe atoms with a 6,6,12-GY framework. The primitive cell is enclosed in blue dashed lines, with grey and orange balls representing C and Fe atoms, respectively. (B) Energy evolution during structure optimization (at 0 K) of “6,6,12-GY + Fe atoms” configuration with fixed lattices, leading to the formation of meta-stable 2D-Fe₃C₁₈. (C) Energy evolution during lattice constant optimization (at 0 K) of meta-stable 2D-Fe₃C₁₈, resulting in the generation of designed 2D-Fe₃C₁₈. (D) Structural schematic showing the origin of FeC₃ and FeC₄ moieties within the skeleton of the designed 2D-Fe₃C₁₈.