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

Abstract

• Benzene ring incorporated g-C 3 N 4 microtubes are fabricated. • This material has improved light harvesting and carrier separation efficiency. • It can be applied in photocatalytic CO 2 reduction with Co(bpy) 3 Cl 2 as co-catalyst. • The catalytic system presents high efficiency and selectivity to CO. • Stability is the most attractive feature for this material. As a promising material for photocatalytic CO 2 reduction, graphitic carbon nitride (CN) and its modification has attracted significant attention. In this work, the in-plane benzene incorporated g-C 3 N 4 microtubes were fabricated via a hydrothermal self-assembly and subsequent thermal polymerization. It is revealed that introducing the π electron-rich benzene ring into the planar structure of g-C 3 N 4 can improve the availability of π 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-C 3 N 4 possesses relatively narrow band gap and enhances light absorption. When the in-plane benzene modified g-C 3 N 4 microtubes were applied to photocatalytic CO 2 reduction with Co(bpy) 3 Cl 2 as co-catalyst, a CO yield up to 322.66 μmol·g −1 ·h −1 was obtained, which was two times in comparison with the pristine g-C 3 N 4 . This work confirms the effectiveness of in-plane benzene modification and 1D hollow structure formation in improving the photoelectric performance of g-C 3 N 4 . Besides, it provides an efficient photocatalytic CO 2 reduction protocol with nonmetallic semiconductor material and earth-abundant metal co-catalyst.