Exfoliated Polymeric Carbon Nitride Nanosheets for Photocatalytic Applications

Exfoliation into a 2D nanosheet structure can lead to enhanced surface activity and unique optical and electronic properties in polymeric carbon nitride (PCN). In this study, four common exfoliation strategies (liquid ultrasonication, thermal oxidation, hydrothermal oxidation, and chemical oxidation) were adopted, and their effects on the structural and electronic changes in PCN were analyzed in detail. This allows us to understand the relationship between the exfoliation mechanism and the structural/optical properties. Here, we demonstrate that the thermal and ultrasonic exfoliation methods can effectively reduce the thickness of PCN while preserving its original structure. In contrast, the chemical and hydrothermal treatments can strongly affect the morphology and structure of PCN, leading to a decreased performance in phenol photodegradation. Therefore, depending on the employed exfoliation method, the surface area, functionalization, band edge positions, charge carrier generation, and mobility are influenced differently up to the point where semiconducting behavior is entirely lost. Our results allow conclusions about the applicability of the different exfoliation methods to obtain distinct material properties for photocatalytic applications.