Jingxian He

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.

Synthesis of PPy/Nano-Graphite Sheets/TbCl3 Composites with High Conductivity

Nano-graphite sheets (NanoGs) were prepared by treating the expanded graphite with sonication in 95% alcohol solution. The polypyrrole (PPy)/NanoGs/TbCl3 nanocomposites were successfully prepared by in-situ polymerization. The structure, morphology, and stability of the composites are characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), and thermogravimetric analysis (TG). The PPy/NanoGs/TbCl3 nanocomposites exhibited much higher electrical conductivity and better thermal property than the pristine PPy. The electrical conductivity of these nanocomposites were adjusted by changing different wt% of the NanoGs and TbCl3, the conductivity of the composites was reached 80.0 S/cm with the 7 wt% of TbCl3 and 3 wt% of NanoGs.

Facile synthesis of highly conductive PPy/graphene nanosheet /Gd3+ composites

Highly conductive PPy/graphene nanosheet and PPy/graphene nanosheet/Gd3+ composites were prepared via in-situ polymerization with p-toluenesulfonic acid as a dopant and FeCl3 as an oxidant. The effects of graphene nanosheet obtained by two different synthetic methods and Gd3+ on the electrical conductivity of the composites were investigated. The results showed that the graphene nanosheet as a filler had an effect on the conductivity of PPy/graphene nanosheet similar to PPy/graphene nanosheet/Gd3+ composites, which played an important role in forming a conducting network in PPy matrix. Thermal gravimetric analysis demonstrated an improved thermal stability of PPy in the PPy/graphene nanosheet/Gd3+ composites. The microstructures of PPy/graphene nanosheet/Gd3+ were characterized by scanning electron microscope and transmission electron microscope examinations.

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.