Controllable Generation of Reactive Oxygen Species on Cyano-Group-Modified Carbon Nitride for Selective Epoxidation of Styrene.

The controlled generation of reactive oxygen species (ROS) to selectively epoxidize styrene is a grand challenge. Herein, cyano-group-modified carbon nitrides (CNCY and CN-T ) are prepared, and the catalysts show better performance in regulating ROS and producing styrene oxide than the cyano-free sample. The diffuse reflectance infrared and density functional theory calculation results reveal that the cyano group acts as the adsorption and activation site of oxygen. X-ray photoelectron spectroscopy and NMR spectrum results confirm that the cyano group bonds with the intact heptazine ring. This unique structure could inhibit HO and OH formation, resulting in high selectivity of styrene oxide. Furthermore, high catalytic activity is still achieved when the system scales up to 2.7 L with 100 g styrene under solar light irradiation. The strategy of cyano group modification gives a new insight into regulating spatial configuration for tuning the utilization of oxygen-active species and shows potential applications in industry.