A comprehensive understanding on the roles of carbon dots in metallated graphyne based catalyst for photoinduced H2O2 production

Photocatalysis is regarded as a sustainable H2O2 manufacturing method. Carbon dots (CDs) are widely used in photocatalysis due to their excellent photoelectric features, while the current understanding of their functions is incomplete. Metallated graphyne is raised as a novel photofunctional 2D organometallic nanosheet which combines the merits of metals and graphynes. To deeply understand the functions of CDs and unlock the potential of mercurated graphyne (HgL1) in photocatalysis, a CDs/HgL1 composite catalyst was constructed. Under visible light, the H2O2 production rate catalyzed by CDs/HgL1 (800 µmol h−1 g−1) is 6.4 times higher than that of pristine HgL1 bulk (125 µmol h−1 g−1). The effects of CDs on HgL1 run through the photocatalytic process, including accelerating the electron-hole separation and migration, improving the redox activity and changing the surface state from hydrophobicity to hydrophilicity. This work offers new avenues for the intelligent design of CDs-based photocatalysts and pioneers the application of metallated graphyne in photocatalysis.