Tailoring the Electronic Structure and Chemical Activity of Iron via Confining into Two-Dimensional Materials

Controllably modulating the atomic electronic structure of active sites is one of the keys for functional material and catalyst design. To understand how the electronic structure is tuned by different chemical environments, we have explicitly explored the geometry structures, electronic features, and magnetic properties by density functional theory (DFT) calculations for iron confined in various two-dimensional (Fe@2D) materials, such as h-BN, graphene, silicene, and silicon-carbon. Iron doping reduces the work function of the 2D materials, gives rise to magnetism, and forms covalent bonding with ligand. Interestingly, it is found that the magnetic moment of the iron atom is zero when replacing a carbon atom of graphene or silicon carbon. The electronic structure of iron is systemically illustrated with the spirit of crystal field theory. The changing of iron electronic structure leads to quite different chemical activity, such as the adsorption of CO, H, C, and O, which are among the important species in catalysis. Meanwhile, iron doping also alters the electronic structure of its environments and activates the inert 2D materials. Our results provide a systematic and electronic level understanding of a class of metal-doped 2D materials and shed light on the design of novel 2D materials for devices and catalysts.