Novel visible-light-driven CQDs/Bi2WO6 hybrid materials with enhanced photocatalytic activity toward organic pollutants degradation and mechanism insight

Novel visible-light-driven carbon quantum dots (CQDs)/Bi2WO6 hybrid materials were synthesized via a facile hydrothermal method. Multiple techniques were applied to investigate the structures, morphologies, optical and electronic properties and photocatalytic performance of as-prepared samples. The nanostructured hybrid material was formed with CQDs attached on the surface of Bi2WO6 sphere-like structure. The photocatalytic activity of the CQDs/Bi2WO6 hybrid materials was evaluated sufficiently by using rhodamine B (RhB), colorless antibiotic agent ciprofloxacin (CIP), tetracycline hydrochloride (TC), and endocrine disrupting chemical bisphenol A (BPA), as target organic pollutants. The as-prepared CQDs/Bi2WO6 hybrid materials exhibited much higher photocatalytic activities than pure Bi2WO6, which showed a broad spectrum of photocatalytic degradation activity. The enhanced activities were attributed to the interfacial transfer of photogenerated electrons from Bi2WO6 to CQDs, leading to effective charge separation of Bi2WO6. The modification by using CQDs (electron acceptor) was an effective way to improve photocatalytic efficiency, which can be extended to a general strategy for other semiconductors. The ESR analysis and free radicals trapping experiments indicated that the O-2(center dot-) and h(+) were the main active species for the photocatalytic degradation. A possible mechanism of CQDs for the enhancement of visible light performance was proposed. (C) 2014 Elsevier B.V. All rights reserved.