Visible light-driven graphitic carbon nitride (g-C3N4) photocatalyzed ketalization reaction in methanol with methylviologen as efficient electron mediator

- Graphitic carbon nitride photocatalyzed ketalization reaction.
- The combination of hole scavenger and electron mediator contribute significantly to the enhanced photocatalytic performance.
- Design strategy could be expanded to other systems for solar energy harvest and conversion.

Ketalization reaction, which is otherwise a typical acid catalyzed process, is herein firstly realized by a novel visible light driven photocatalytic reaction system with methylviologen (MV2+) as an efficient electron mediator and graphitic carbon nitride (g-C3N4) as the visible light sensitizer. The photons utilization efficiency of g-C3N4 was maximized by simultaneous removal of the conduction band electrons and valence band holes by MV2+ and methanol, respectively. The turn over number of MV2+ reaches the remarkable high value of 31201/hour, with 72.7 mmol of cyclohexanone dimethyl ketal production in 1 h. The design strategy presented in this work could inspire the development of new and highly efficient photocatalytic reaction systems for broader purposes than usually expected.

Ketalization reaction, which is otherwise a typical acid catalyzed process, is herein realized by a novel visible light driven photocatalytic reaction system with methylviologen (MV2+) as the electron mediator and graphitic carbon nitride (g-C3N4) as the photocatalyst. The combination of the electron mediator and hole scavenger in one photocatalytic reaction system significantly improves the utilization efficiency of the photo-induced charges.170