Bioinspired Synthesis of Carbon Dots/g-C₃N₄ Nanocomposites for Photocatalytic Application

This study reports a fast and green preparative strategy to synthesize water soluble and fluorescent carbon quantum dots (CQDs) through hydrothermal method by using low cost organic waste of human fingernails as the carbon precursor for the first time. The coupling of CQD with pure carbon nitride (g-C₃N₄) was further explored to enhance the latter’s performance in photocatalysis of 2,4-dicholorophenol (2,4-DCP), a toxic and recalcitrant compound mostly released from industrial effluent. Such coupling overcame the weakness of pure g-C₃N₄ in photocatalysis process by broadening its visible light absorption and promoting the charge separation. As a result, the removal rate of CQD/ g-C₃N₄(10) was up to 71.53%, which was approximately 1.5 times higher than that of pure g-C₃N₄ under sunlight irradiation. The morphological structure, optical properties and chemical compositions of CQDs/g-C₃N₄ composites were characterized using various spectroscopic techniques including field emission scanning electron microscopy (FESEM), Energy Dispersive X-Ray (EDX) and Ultraviolet-visible diffuse reflectance spectra (UV-DRS).