Divalent\nFe Atom Coordination in Two-Dimensional Microporous\nGraphitic Carbon Nitride

Abstract

Graphitic carbon nitride (<i>g</i>-C₃N₄) is a rising two-dimensional\nmaterial possessing intrinsic\nsemiconducting property with unique geometric configuration featuring\nsuperimposed heterocyclic sp² carbon and nitrogen network,\nnonplanar layer chain structure, and alternating buckling. The inherent\nporous structure of heptazine-based <i>g</i>-C₃N₄ features electron-rich sp² nitrogen, which\ncan be exploited as a stable transition metal coordination site. Multiple\nmetal-functionalized <i>g</i>-C₃N₄ systems have been reported for versatile applications, but local\ncoordination as well as its electronic structure variation upon incoming\nmetal species is not well understood. Here we present detailed bond\ncoordination of divalent iron (Fe²⁺) through micropore\nsites of graphitic carbon nitride and provide both experimental and\ncomputational evidence supporting the aforementioned proposition.\nIn addition, the utilization of electronic structure variation is\ndemonstrated through comparative photocatalytic activities of pristine\nand Fe-<i>g</i>-C₃N₄.