Yanli Chang

A Facile One‐step Method to Produce Graphene–CdS Quantum Dot Nanocomposites as Promising Optoelectronic Materials

[*] Prof. A. Cao, Z. Liu, Prof. M. Wu, Z. Ye, Z. Cai, Y. Chang, Prof. Y. Liu Institute of Nanochemistry and Nanobiology Shanghai University, Shanghai, 200444 (P. R. China) E-mail: ancao@shu.edu.cn Prof. S. Wang, S. Chu, Prof. Q. Gong State Key Laboratory for Mesoscopic Physics, School of Physics Peking University, Beijing, 100871 (P. R. China) E-mail: wangsf@pku.edu.cn Prof. Y. Liu Beijing National Laboratory of Molecular Science College of Chemistry and Molecular Engineering Peking University, Beijing, 100871 (P. R. China) E-mail: yliu@pku.edu.cn

Removal of methylene blue from aqueous solution by graphene oxide.

Graphene oxide (GO) is a highly effective absorbent of methylene blue (MB) and can be used to remove MB from aqueous solution. A huge absorption capacity of 714 mg/g is observed. At initial MB concentrations lower than 250 mg/L, the removal efficiency is higher than 99% and the solution can be decolorized to nearly colorless. The removal process is fast and more efficient at lower temperatures and higher pH values. The increase of ionic strength and the presence of dissolved organic matter would further enhance the removal process when MB concentration is high. The results indicate that GO can be applied in treating industrial effluent and contaminated natural water. The implications to graphene-based environmental technologies are discussed.

Folding/aggregation of graphene oxide and its application in Cu2+ removal.

Graphene oxide (GO) can be aggregated by Cu(2+) in aqueous solution with a huge Cu(2+) absorption capacity. The Cu(2+) causes GO sheets to be folded and also to form large aggregates that were characterized by confocal microscopy and atomic force microscopy. The folding/aggregation is most likely triggered by the coordination between GO and Cu(2+). The equilibrium Cu(2+) concentrations and equilibrium absorption capacity of GO were measured to estimate the maximum absorption capacity of GO for Cu(2+) and the absorption model. GO has a huge absorption capacity for Cu(2+), which is around 10 times of that of active carbon. Representative results are presented and the implication to Cu(2+) removal is discussed.

Effect of size and dose on the biodistribution of graphene oxide in mice

AIM Graphene oxide (GO) has promising applications in bioimaging, diagnostics and therapeutics. This work studied the effects of size and injection dose on the biodistribution of GO to accelerate the development of a GO-based drug. METHODS GO samples were intravenously injected into mice. The content of GO in organs/tissues at different time points was measured using an (125)I-labeling technique. GO in the liver and lungs was further confirmed by both Raman spectroscopic and TEM observations. The dispersion state of GO in serum was evaluated by flow cytometry. RESULTS Regardless of size, GO was cleared from the blood quickly and accumulated mainly in the liver and lungs. The uptake of GO in lungs increased with increasing injection dose and size. The dispersion state (i.e., size of the GO-protein complex in blood) dominated the biodistribution. CONCLUSION The size and dose of GO affected its fate in vivo. For medical applications, small-sized GO with suitable funtionalization is recommended.

Synthesis of single-layer graphene-quantum dots nanocomposite directly from graphene oxide

Graphene is currently one of the hottest materials, its excellent electrical conductivity and its thin flexible two-dimensional feature make it a superior component for nanocomposite materials, for example being a transparent window electrode for dye-sensitized solar cells. However, one of the biggest obstacles to graphene research is to obtain single-layer graphene in large quantity. We reported here a simple strategy to fabricate graphene-quantum dots nanocomposite via a facile one step reaction from the soluble graphene oxide, this approach avoids the above obstacle by skipping the graphene production step, and may be used to fabricate other graphene nanocompistes.