Corn-straw-derived CQD-modified g-C3N4/NiCo-LDH composite for photocatalytic CO2 reduction

Corn-straw-derived CQDs are prepared via a hydrothermal method. • CN/NC/CQDs-6 achieves a CO evolution rate of 37.37 μmol g −1  h −1 . • CQDs improve charge separation and facilitate interfacial charge transport. Photocatalytic CO 2 reduction is a promising approach for mitigating energy shortages and carbon emissions. Herein, graphitic carbon nitride (g-C 3 N 4 ) was employed as the substrate and combined with hydrothermally synthesized NiCo-LDH, followed by the introduction of carbon quantum dots (CQDs) to fabricate a series of CN/NC/CQDs-x ternary composites. The composite exhibited enhanced absorption in the visible spectral region and improved photoinduced charge-separation behavior. Meanwhile, the integration of NiCo-LDH, g-C 3 N 4 , and CQDs promoted interfacial coupling, suppressed the recombination of photogenerated carriers, and facilitated charge separation and transport within the ternary composite. In addition, the CO 2 photoreduction activity of CN/NC/CQDs-x composites was evaluated. Among the prepared samples, CN/NC/CQDs-6 shows the best photocatalytic performance, achieving a CO generation rate of 37.37 μmol g −1  h −1 , which is 26.31 times that of pristine g-C 3 N 4 . This work provides insights into the development of biomass-derived CQD-modified g-C 3 N 4 photocatalysts for efficient CO 2 reduction.