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3D porous framework composed of exfoliated ultrathin nanosheets is a hot topic in the field of energy storage and conversion. A facile method to prepare 3D mesoporous C3N4 with few-layered nanosheets interconnected in large quantity via H2SO4 intercalation and subsequent thermal treatment was described herein. The obtained thermally-exfoliated C3N4 (TE-C3N4) was thoroughly characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), UV-Vis diffuse reflectance spectroscopy (DRS) and Brunauer-Emmett-Teller (BET) measurements. The detailed analysis indicated that TE-C3N4 possessed enlarged inter-layer space, enhanced UV-light adsorption and high specific surface area with 3D interconnected structure composed of ultrathin 2D nanosheets. Compared to bulk C3N4, TE-C3N4 showed an enhanced photocatalytic activity for photodegradation of Rhodamine B under UV-light irradiation and exhibited no significant loss of photocatalytic activity after 11 recycled runs. The pseudo-first reaction rate constant for TE-C3N4 was about four times higher than that for pure bulk-C3N4. The better photocatalytic performance could be attributed to more active catalytic sites, prolonged photo-excited carrier lifetime and shorted pathway of the carriers to the reaction sites.

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Graphitic-C3N4 nanosheets (CN)/ZnO photocatalysts (CN/ZnO) with different CN loadings were successfully prepared via a simple precipitation-calcination in the presence of exfoliated C3N4 nanosheets. Their morphology and structure were thoroughly characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS) and photoluminescence spectra (PL). The results showed that hexagonal wurzite-phase ZnO nanoparticles were randomly distributed onto the CN nanosheets with a well-bonded interface between the two components in the CN/ZnO composites. The performance of the photocatalytic Cr(VI) reduction indicated that CN/ZnO exhibited better photocatalytic activity than pure ZnO under visible-light irradiation and the photocatalyst composite with a lower loading of CN sheets eventually displayed higher activity. The enhanced performance of CN/ZnO photocatalysts could be ascribed to the increased absorption of the visible light and the effective transfer and separation of the photogenerated charge carriers.

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Magnetic targeted drugs delivery system (MTDDS) is a new targeted drug system, which can greatly reduce the dosage and improve the therapeutic efficiency of medicine. Currently superparamagnetic ferric oxide plays important function as targeted drug in the treatment of tumors, but cytotoxicity was still regarded as side effect in the process of drug. In this paper, we take advantage of drug carrier (ferric oxide) toxicity controlling cancer cell growth in cancer treatment, increasing targeted drug efficiency. We applied the modified chemical precipitation method to prepare polylactic acid (PLA) coated high-purity superparamagnetic Fe 3 O 4 nanoparticles for targeted drug, characterized PLA/Fe 3 O 4 microspheres physical and chemical properties, and then investigated cytotoxicity influence of PLA/Fe 3 O 4 nanomagnetic microspheres as carrier for normal liver cells (7701) and liver cancer cells (HePG2) in different concentration; results of MTT and hemolysis and micronucleus test showed that carrier restrained the growth of HePG2 in special concentration, meanwhile the proliferation rate of liver cells was not affected. The study demonstrates that compared with liver cell, liver cancer cells (HepG2) are easy to be disturbed by PLA/Fe 3 O 4 nanomagnetic microsphere, which have higher sensitivity and absorption ability. We hope to take advantage of the susceptible property of cancer cells for carriers to improve targeted drug function.

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