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Synthesis of 3D CQDs/urchin-like and yolk-shell TiO2 hierarchical structure with enhanced photocatalytic properties
摘要： A novel CQDs/TiO2 hierarchical structure with enhanced photocatalytic properties was achieved by uniformly decorating urchin-like and yolk-shell TiO2 microspheres (UYTMs) with carbon quantum dots (CQDs) through an environmentally friendly hydrothermal process. The CQDs were ?rstly synthesized by the electrochemical method, and the TEM, Raman and PL characterizations strongly indicated that the as-prepared CQDs exhibited good dispersion, high crystallinity and unique up-conversion properties. The UYTMs synthesized by a NaOH-assisted hydrothermal process showed stable 3D hierarchical structure and large surface area, which was bene?cial for light absorption and contacting with contamination. The good combination of CQDs and UYTMs was further successfully achieved during the hydrothermal process, and demonstrated by a series of tests. The photocatalytic experiments suggested that the CQDs/UYTMs exhibited better photocatalytic activities than the pure UYTMs and P25 under both visible and UV light irradiation. The CQDs/UYTMs combining with 6 wt% of CQDs showed the best photocatalytic e?ciency, while excessive CQDs tended to inhibit the photocatalytic activity. According to the results and discussions, a possible mechanism in improving the photocatalytic e?ciency of the CQDs/UYTMs is signi?cantly proposed. The up-conversion property of CQDs can broaden the absorption spectrum of CQDs/UYTMs to the visible light. Moreover, the CQDs, as the electron reservoirs, are e?cient to separate the electrons and holes, leading to an improved photocatalytic activity of CQDs/UYTMs.
关键词： Carbon quantum dots,Urchin-like microspheres,Photocatalytic activity,TiO2,Yolk shell
更新于2025-09-23 15:19:57
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Synthesis of Urchin-like and Yolk-shell TiO <sub/>2</sub> microspheres with enhanced photocatalytic properties
摘要： The novel urchin-like and yolk-shell titania microspheres (henceforth called UYTMs) with nanowires/microspheres hierarchical structures were successfully synthesized by a synthetic sol-gel and hydrothermal method without using any template. Uniform TiO2 microspheres were firstly prepared by the sol-gel method, and the great monodispersed properties was delicately regulated by using the surfactant of KCl, aniline and a proper amount of water. The urchin-like yolk-shell morphology was further achieved by a NaOH-assisted hydrothermal process, and the diameter and shell thickness of the UYTMs were highly controlled by the concentration of NaOH. The detailed morphology, chemical composition and crystallinity of the UYTMs were systematically characterized by several techniques, and the underlying formation mechanisms was attentively discussed as well. The photodegradation of methylthionine chloride experiments indicated the UYTMs showed much better photocatalytic activity than that of commercial P25. This is mainly because the UYTMs exhibited much more reactive sites, higher adsorption ability and tuned optical absorption behavior owing to their large specific surface area, hierarchical structures and the special hollow yolk-shell structure.
关键词： Titania,NaOH-assisted hydrothermal synthesis,Photocatalytic activity,Yolk-shell,Urchin-like microspheres
更新于2025-09-10 09:29:36