General surface grafting strategy-derived carbon-modified graphitic carbon nitride with largely enhanced visible light photocatalytic H2 evolution coupled with benzyl alcohol oxidation

Carbon-modified g-C3N4 manifests increasing prospects in the photocatalytic realm. However, there are some challenges, such as difficult large-scale preparation, weak interface connection, limited active sites, and inefficient light utilization, which restrain the further utilization for carbon modified g-C3N4. To solve these disadvantages, we recommended a novel and general surface grafting strategy followed by the in situ carbonization treatment to obtain carbon-modified graphitic carbon nitride (CMCN). Experimental results disclose that the introduced carbon connected intimately with g-C3N4 by edge N atoms, which dramatically improve the charge transfer kinetics. CMCN presents incredibly reinforced visible light photocatalytic activity with an impressive hydrogen evolution rate of 5.549 mmol g(-1) h(-1), which is about 13.3 times higher than that of pure g-C3N4. Theoretical calculation results show that the introduced carbon can form a new intermediate state between the bandgap, which could capture the photoexcited electrons and reinforce the visible light absorption. Importantly, the practicality of the CMCN material is further demonstrated by replacing a sacrificial reagent with benzyl alcohol conversion to produce value-added benzaldehyde, where the decent evolution rates of 0.288 and 0.230 mmol g(-1) h(-1) can be achieved for H-2 and benzaldehyde, respectively.

Automated summary

The novel surface grafting strategy followed by in situ carbonization treatment can effectively improve the photocatalytic performance of carbon-modified g-C3N4, resulting in CMCN with enhanced visible light activity. The introduced carbon intimately connects with g-C3N4 to improve charge transfer kinetics and capture photoexcited electrons by forming a new intermediate state. The experimental results also demonstrate the practicality of CMCN material for producing high value-added benzaldehyde.