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 μmol 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 ·− 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.