Abstract:

Ionic-liquid-modified carbon quantum dots （L-CQDs） were prepared by one-pot pyrolysis using citric acid as carbon source and 1-aminopropyl-3-methyl-imidazolium bromide as surface modifier. TiO₂ nanoparticles were loaded with L-GQDs by one-step hydrothermal method. Using a solution of nonylphenol polyoxyethylene ether （TX-10） as the simulated wastewater, the photocatalytic performance of L-CQDs/TiO₂ composite photocatalyst was studied. The characterization results are proved by FT-IR and high-resolution transmission electron microscopy （HRTEM） that L-CQDs are loaded onto the surface of TiO₂ nanoparticles. The UV-visible absorption spectrum show that the absorption of L-GQDs/TiO₂ in the visible region is significantly enhanced compared with TiO₂ nanoparticles. The results of photocatalysis show that the degradation rate of 3% L-CQDs/TiO₂ to 0.05 g/L TX-10 solution could reach 83.5% under illumination of Xenon lamp for 3 h, which is 26.6% higher than that of TiO₂ nanoparticles. The photocatalytic activity of the composite photocatalyst remain unchanged after repeated use for 5 times.

Key words: carbon quantum dots, composite photocatalyst, TiO₂, photocatalysis, nonylphenol polyoxyethylene ether