Zunli Mo

Preparation and Characterization of Graphene/Europium Oxide Composites

Eu2O3/graphene nanocomposites have been synthesized using graphite oxide and europium nitrate as precursor for graphene and europium oxide, respectively. Graphene coated by nanosized Eu2O3 particles has been confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. TEM analysis images illustrated that the as-formed Eu2O3 nanoparticles were densely and uniformly deposited on the graphene nanosheets. The good distribution of Eu2O3 nanoparticles on graphene nanosheets improved the thermal stability of Eu2O3/graphene namocomposites. A plausible mechanism for formation of the intriguing nanocomposite has been proposed. Moreover, Eu2O3/graphene nanocomposites exhibited both optical and electrical properties. These Eu2O3/graphene nanocomposites show potential applications in electronic and optoelectronic systems.

One-step hydrothermal synthesis of magnetic responsive TiO2 nanotubes/Fe3O4/graphene composites with desirable photocatalytic properties and reusability

Here, we report a facile approach to preparing a magnetic responsive TiO2 nanotubes/Fe3O4/graphene composite (TNTs/Fe3O4/GN), in which the reduction of graphene oxide as well as the formation of Fe3O4 nanoparticles and TNTs occurred simultaneously. The preparation time and procedure were effectively simplified and shortened. A series of techniques including XRD, TEM, BET, VSM and EDX were employed to characterize the composite. Also, the photocatalytic activity of the composite was evaluated via the removal of methylene blue. The results showed that TNTs and Fe3O4 nanoparticles were deposited on layers of GN, and a synergistic effect was observed in the composite. Owing to interfacial contact between TNTs and GN, the recombination of photogenerated electrons/holes was suppressed and the photocatalytic performance was enhanced. The composite not only displayed higher photocatalytic activity than TNTs and P25, but also exhibited desirable reusability and rapid separation performance, which make it a potential candidate for applications in wastewater treatment.

An electrochemical chiral sensor for tryptophan enantiomers based on reduced graphene oxide/1,10-phenanthroline copper(II) functional composites

An electrochemical chiral sensor based on reduced graphene oxide (RGO) non-covalently functionalized with 1,10-phenanthroline copper(II) (PhenCu) complex has been developed for electrochemical discrimination of tryptophan (Trp) enantiomers. The formation and morphology of reduced graphene oxide/1,10-phenanthroline copper(II) (RGO/PhenCu) composites were confirmed by Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Cyclic voltammetry (CV) was employed to monitor the electrochemical behavior of RGO/PhenCu immobilized on glassy carbon electrode (RGO/PhenCu/GCE). The reduction in peak current was significantly different when the chiral sensor interacted with L-Trp and D-Trp. This suggested that RGO/PhenCu/GCE could be used as an electrochemical chiral sensor for the discrimination of Trp enantiomers. Further studies showed that the peak current decreased linearly along with an increasing percentage of L-Trp in the Trp mixture. The RGO/PhenCu/GCE electrochemical chiral sensor, with rapid recognition, good sensitivity and high stability, provided an efficient method to recognize and discriminate Trp enantiomers.

Fabrication of Polyaniline/Graphene/Tb3+ Conductive Composite Material

Polyaniline/graphene/Tb3+(PANI/GN/Tb3+) composite material was successfully prepared by the method of in-situ polymerization. The morphology of this as-formed composite material has been confirmed by scanning electron microscope (SEM) analysis. SEM images illustrated that the PANI were uniformly deposited on GN nanosheets. PANI/GN/Tb3+ composite material exhibited high electrical conductivity than the pristine PANI. Whats more, results also demonstrated that the synthesized composite material has found wide promising applications in capacitors. Finally, the conductive mechanism of PANI/GN/rare earth composite is discussed in this paper, the conductivity of nanocomposites offered upgrade first than descending latter tendency with different content of Tb3+ ions. The results should be attributed to the special electronic structure and excellent magnetic of rare earth ions, which can influence the polymer chains.

Synthesis and Characterization of NanoGs-PPy/Epoxy Nanocomposites by In Situ Polymerization

NanoGs-PPy/epoxy nanocomposites were successfully prepared by in situ polymerization of pyrrole in the presence of NanoGs. The morphology and stability of the materials were characterized by scanning electron microscope and thermogravimetric analysis. Electrical conductivity and mechanical properties of the composites were also investigated. The results showed that the NanoGs-PPy/epoxy composites not only maintained its good electrical conductivity but also keep favorable mechanical properties.

The construction and application of chiral electrochemical sensors

The review is based on the construction and application of chiral electrochemical sensors in the last three years and presents recent advances in applications of chiral electrochemical sensors based on a three-point interaction and the methods for fabricating chiral surfaces for enantioselective recognition.

Superparamagnetic functional C@Fe3O4 nanoflowers: development and application in acetaminophen delivery

Fe3O4 nanoflowers (NFs) were synthesized via an aqueous solution method and coated with carbon through an in situ carbonization process. The synthesized C@Fe3O4 composites were further modified with strong oxidizing agents, forming functional C@Fe3O4 (FCF) flower-like composites with porous superstructure. Finally, the stable composites were used in the drug delivery test under ambient conditions; the amount of acetaminophen adsorption on the composite can weigh up to 25.07% in 3 h. The FCF composites show excellent porosity (165.23 m2 g-1) and magnetic properties (24.33 emu g-1). The -COOH, C[double bond, length as m-dash]O and -OH groups in the composites could be used for interaction with biomolecules that contain -OH, C[double bond, length as m-dash]O and -NH2 groups. Therefore, the composite exhibits a sustained release model, with release rates of 51% in the first 6 h and 73% in 12 h. This special character gives the composites potential to be used in magnetic bio-separation and drug/gene delivery. The findings in this study are useful for the engineering design of porous iron oxide coated with functional carbon that is used for medical delivery applications and other biomedical devices.

The construction of electrochemical chiral interfaces using hydroxypropyl chitosan

A simple chiral electrochemical sensor based on hydroxypropyl chitosan (HPCS) covalently bound to multi-walled carbon nanotubes (MWCNTs) was developed for the recognition of mandelic acid (MA) enantiomers. HPCS preferably combines with (S)-MA over (R)-MA, which was attributed to the favorable host–guest interactions between HPCS and the MA enantiomers. In addition, the recognition efficiency was significantly increased after hydroxypropyl groups were grafted onto chitosan (CS), which may be due to a stereo-hindrance effect. Moreover, the electrochemical recognition of amino acid enantiomers was investigated; the functional groups of the enantiomers play an important role in the enantioselective discrimination.

Fabrication of NanoGs/PPy/Polymethacrylate (PMMA)-Epoxy Conductive Films

Nanographite sheets (NanoGs)/polypyrrole (PPy)/polymethacrylate (PMMA)–epoxy conductive films have been successfully prepared. NanoGs were prepared by treating the expanded graphite with sonication in aqueous alcohol solution. Then nanocomposite films were fabricated by in-situ polymerization of pyrrole in the presence of NanoGs by using epoxy resin and PMMA blends as copolymer matrix. From the thermogravimetric analysis, the introduction of epoxy resin and a few PMMA blends exhibited a beneficial effect on the thermal stability of pure PPy. According to the four-point probe test, the conductivity of the final nanocomposite films was about 1.5 × 10−3 s/cm.

Preparation and characterisation of PPy/NanoGs/Fe3O4 conductive and magnetic nanocomposites

Nanocomposites composed of polypyrrole (PPy), graphite nanosheets (NanoGs), magnetite (Fe3O4) nanoparticles, have been successfully synthesised with a two-step process. First, we prepared NanoGs/Fe3O4 powder via wet chemical co-precipitation method. Next, pyrrole was polymerised in the suspension of NanoGs/Fe3O4 and then PPy/NanoGs/Fe3O4 nanocomposites were produced. The products were characterised by Fourier-transform infrared spectroscopy, Transmission electron microscopy, Thermogravimetric, conductivity and magnetisation analysis. The result showed that the conductivity of the PPy/NanoGs/Fe3O4 composites, compared with pure PPy, increased dramatically. And the saturation magnetisation of nanocomposites increased with the increase of the volume fraction of the Fe3O4 particles. In addition, according to the thermal gravimetric analysis, compared with PPy, nanocomposites exhibited enhanced thermal stability due to the introduction of NanoGs/Fe3O4. The PPy/NanoGs/Fe3O4 composites show potential applications in electric–magnetic shield materials.