Visible–ultraviolet upconversion carbon quantum dots (CQDs) are synthesized with a hydrothermal method using l -glutamic acid ( l -Glu) and m -phenylenediamine (MPD) and then combined with commercial nano-TiO 2 to prepare CQDs/TiO 2 composites. The fluorescence spectra prove that the prepared CQDs can convert approximately 600 nm visible light into 350 nm ultraviolet light. In photocatalysis experiments, CT-1, a CQDs/TiO 2 composite with 1:1 molar ratio of l -Glu to TiO 2 , has the best degradation efficiency for methyl orange (MO). Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) experiments confirm that CT-1 is composed of quasi-spherical nano-TiO 2 and CQDs with a crystal plane of graphitic carbon. CT-1 can degrade 70.56% of MO (40 ppm) within 6 h under the irradiation of a 600 nm light source, which is close to its degradation rate of 78.75% under 365 nm ultraviolet light. The apparent rate constant of CT-1 degradation equation is 12.7 times that of TiO 2 . Free radical scavenging experiments and electron spin resonance (ESR) tests show that the degradation ability should be attributed to the existence of h + and • OH under visible light. Therefore, we provide a simple and low-cost solution with heavy-metal-free products to improve the photocatalytic performance of TiO 2 .

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Eco-friendly waterborne polyurethane-acrylate with high-performance via incorporation of cationic TiO2/reduced graphene oxide.

Multifunctional theranostic systems are a recent important development of medical research. We combined the characteristics of near-infrared luminescent quantum dots and thermosensitive magnetoliposomes to develop a multifunctional nano-diagnostic material. This system is based on near-infrared magnetic thermosensitive liposomes, which encapsulate drugs and can control drug localization and release. After incubating cancer cells with the liposomes, the state of the cells was analyzed in real time by near-infrared imaging. Cell viability was significantly inhibited by heat treatment or alternating magnetic field treatment, which thus improved the anti-cancer properties of the liposomes. In the future, by combining near-infrared imaging technology and an external high-frequency alternating magnetic field, we could not only detect cancer cells noninvasively but also conduct image-guided treatments for cancer.