Molecular engineering of g-C3N4 with spatial charge separation for enhancing photocatalytic performances

The intramolecular doping of donor units or acceptor units in carbon nitride (g-C3N4, CN) is regarded as an effective method for regulating electron structure and enhancing the catalytic activity of CN. Herein, benzene rings and eosin Y (EY) co-grafted CN with carbon vacancies (EY-PhCN) was prepared by calcining a supermolecular precursor consisting of melamine, cyanuric acid, and benzonquanmine followed by covalently hooking the EY. Theoretical and experimental results demonstrated the directional electron transfer, spatially isolated electron-hole pairs and increased light response in the resulting ultrathin holey EY-PhCN. An optimal H-2 production rate of 4.44 mmol g(-1) h(-1) was obtained over the 1%Pt-loaded EY-PhCN catalyst. The corresponding apparent quantum yield was 27.38% at 420 nm. Moreover, the EY-PhCN exhibited high CO2 reduction rate with H2O. The yields of CO and CH4 were 61.91 and 13.75 mu mol g(-1), respectively within 5 h light irradiation, higher than that of CN (CO: 24.60 mu mol g(-1), CH4: 8.51 mu mol g(-1)). The work may give new insight into associating carbon vacancies and edge decoration on CN to achieve remarkably enhanced photocatalytic activity.