Correlating Photochemical Behavior with Material and Optical Properties in Graphitic Carbon Nitride

The tunable structural and chemical properties of graphitic carbon nitride (gCN) provide a promising route toward tailored activity in photocatalytic applications. A primary challenge in optimizing gCN toward this end is its intrinsically heterogeneous structure, due in part to the many parameters employed in its synthesis. Variability in type and density of chemical and structural defects simultaneously change the electronic, photocatalytic, and optical properties of gCN. Here, we elucidate the complicated structure–function relationship in a series of three related gCN samples by correlating photochemical activity to a host of structural, chemical, and spectroscopic characterization techniques. Of the 22 physical properties measured, we find that transient absorption spectroscopy lifetimes are the only observable that trends with photochemical activity across the series. These results show that a key challenge to photocatalytic material optimization stems from covariant material properties that have competitive influences on photocatalytic activity, making the determination of a robust structure–function relationship challenging.