Construction of a Novel Ternary GQDs/g-C 3 N 4 /ZIF-67 Photocatalyst for Enhanced Photocatalytic Carbon Dioxide Reduction.

In this study, graphene quantum dots (GQDs) have been incorporated into the g-C₃N₄/ZIF-67 heterojunction system as a photosensitizer to enhance photocatalytic conversion of CO₂-to-CO. The GQDs are deposited onto the surface of g-C₃N₄/ZIF-67 using a simple water bath procedure. As expected, GQDs/g-C₃N₄/ZIF-67 presents outstanding performance in CO₂ photoreduction. Among the GQDs/g-C₃N₄/ZIF-67 ternary photocatalysts, 7 GQDs-CN/ZIF-67 exhibits the best photocatalytic CO₂ reduction ability with a CO yield of 51.71 μmol g⁻¹, which is 5.05 and 1.87 times more than pristine g-C₃N₄ (10.24 μmol g⁻¹) and g-C₃N₄/ZIF-67 (27.65 μmol g⁻¹), respectively. This result shows that upon combination of GQDs with ZIF-67/g-C₃N₄, GQDs can be used as photosensitizers to improve the optical absorption capacity of the photocatalyst. Furthermore, GQDs serve as electron channels, facilitating the transport of photo-induced electrons from ZIF-67 to g-C₃N₄, which promotes photogenerated carrier separation efficiency. This study innovatively adds GQDs to the heterojunction and applies the prepared ternary composite to the CO₂ photoreduction, which inspires a novel direction for the design of non-noble metal photocatalysts. [ABSTRACT FROM AUTHOR]