In-plane benzene incorporated g-C3N4 microtubes: Enhanced visible light harvesting and carrier transportation for photocatalytic CO2 reduction

As a promising material for photocatalytic CO2 reduction, graphitic carbon nitride (CN) and its modification has attracted significant attention. In this work, the in-plane benzene incorporated g-C3N4 microtubes were fabricated via a hydrothermal self-assembly and subsequent thermal polymerization. It is revealed that introducing the pi electron-rich benzene ring into the planar structure of g-C3N4 can improve the availability of pi electron and create the local asymmetry of heptazine structure. As a result, the separation and transportation of photogenerated charges are improved. Furthermore, the modified g-C3N4 possesses relatively narrow band gap and enhances light absorption. When the in-plane benzene modified g-C3N4 microtubes were applied to photocatalytic CO2 reduction with Co(bpy)(3)Cl-2 as co-catalyst, a CO yield up to 322.66 mu mol.g(-1).h(-1) was obtained, which was two times in comparison with the pristine g-C3N4. This work confirms the effectiveness of in-plane benzene modification and 1D hollow structure formation in improving the photoelectric performance of gC(3)N(4). Besides, it provides an efficient photocatalytic CO2 reduction protocol with nonmetallic semiconductor material and earth-abundant metal co-catalyst.

Automated summary

In this study, graphitic carbon nitride (g-C3N4) was modified by introducing pi electron-rich benzene rings, which improved the availability of pi electron and created local asymmetry in the heptazine structure. This modification enhanced the separation and transportation of photogenerated charges, as well as enhanced light absorption. The in-plane benzene modified g-C3N4 microtubes showed a CO yield two times higher than pristine g-C3N4 when used in photocatalytic CO2 reduction. This work highlights the effectiveness of in-plane benzene modification and 1D hollow structure formation in improving the photoelectric performance of g-C3N4, and provides a efficient protocol for CO2 reduction using nonmetallic semiconductor material and earth-abundant metal co-catalyst.