Carbon nitride quantum dots-modified cobalt phosphate for enhanced photocatalytic H2 evolution

In the present work, carbon nitride quantum dots (CNQDs)-modified cobalt phosphate (CoPi) composites CNQDs/CoPi--x (x = 1, 2, 3) were prepared at room temperature and characterized by FTIR, XRD, UV-Vis DRS, EIS, SEM, TEM/ HR--TEM, XPS, and N-2 gas adsorption. The morphologies and surface areas of CNQDs/CoPi-x have no remarkable change after modification of CNQDs, compared with pure CoPi. The obtained CNQDs/CoPi-x shows enhanced activity and stability of photocatalytic H-2 evolution compared to pure CoPi using Eosin Y (EY) as a sensitizer and triethanolamine as an electron donor. The CNQDs/ CoPi-2 possesses the highest hydrogen evolution rate, 234.5 mu mol h(-1) g(-1), upon visible light, which outshines that of CoPi by 2.4 times. It was believed that the enhanced photocatalytic performances of the CNQDs/CoPi-2 could result from the boosted electron transfer from radical EY center dot- to CNQDs/CoPi-2 by the employment of CNQDs; in addition, the visible-light activity of CNQDs contributes to hydrogen evolution. The mechanism of photocatalytic hydrogen production was discussed. This study may contribute toward the development of production of green hydrogen using solar.

Automated summary

In this study, carbon nitride quantum dots (CNQDs)-modified cobalt phosphate (CoPi) composites CNQDs/CoPi-x (x=1, 2, 3) were synthesized and characterized. The modified CNQDs/CoPi-x showed enhanced photocatalytic activity and stability for hydrogen evolution compared to pure CoPi. The highest hydrogen evolution rate was achieved by CNQDs/CoPi-2, which was 2.4 times higher than that of CoPi. The improved performance was attributed to boosted electron transfer and visible-light activity of CNQDs.