The multiwalled carbon nanotubes (MWCNTs) wrapped with face-centered cubic ZnS nanospheres with a uniform and small diameter have been prepared to form MWCNT/ZnS heterostructures by microwave irradiation. Zinc acetate (Zn(Ac) 2 ) and thioacetamide (TAA) were used as the zinc and sulfur sources, respectively. The dispersion, morphology, ratio of loading, and size of the ZnS nanospheres in the range of 11.7 to 24.5 nm can be controlled easily by adjusting the microwave power, the initial concentration of Zn(Ac) 2 , and the molar ratios of Zn(Ac) 2 /TAA and Zn(Ac) 2 /MWCNTs. The heterostructures have been characterized by X-ray powder diffraction, and scanning and transmission electron microscopy. The results show that the surfaces of MWCNTs are not only randomly decorated with ZnS layers composed of uniform ZnS nanoparticles but also show that some spherelike ZnS nanoparticles are aggregated and deposited on the ZnS layers. A photoluminescence spectrum showed that the MWCNT/ZnS heterostructures feature a broad blue emission at around 432 nm (λ ex ) 376 nm). The MWCNT/ZnS heterostructures also show an excellent photocatalytic activity toward the photodegradation of methyl orange.

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A new electrochemical sensor based on copper nanoparticles (Cu NPs) and multi-walled carbon nanotubes (MWCNTs) was fabricated for the determination of hydroquinone (HQ).

A highly efficient electrochemical sensor consisted by gold nanoparticles (Au NPs)loaded on reduced graphene oxide (RGO) nanosheets for Cu 2+ and Hg 2+ was developed. The electrochemical performances of as-prepared bare glassy carbon electrode (GCE), RGO/GCE, Au NPs@RGO/GCE were characterized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), respectively. The Au NPs@RGO/GCE exhibited an excellent sensitivity toward Cu 2+ and Hg 2+ . The results revealed that the detection limit of Cu 2+ was 0.0015 μM and Hg 2+ was 0.02 μM (S/N = 3). In addition, the Au NPs@RGO nanocomposite modified electrode was optimized and applied for practical water sample analysis with a satisfactory outcome. The electrochemical sensor based on Au NPs@RGO would be expected to expand the application field of heavy metal detection.

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Fe 46 Co 35 Ni 19 /CNTs nanocomposites have been prepared by an easy two-step route including adsorption and heat treatment processes. We investigated the effect of heat treatment conditions on structure, morphology, nanoparticle sizes and magnetic properties of the Fe 46 Co 35 Ni 19 alloy nanoparticles attached on the carbon nanotubes by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-disperse X-ray spectroscopy (EDS) and vibrating sample magnetometer (VSM). When the reducing temperature changes from 300-450°С, a transition of the crystalline structure from bcc phase to fcc-bcc dual phase and an increase in particle size of Fe 46 Co 35 Ni 19 nanoparticles together with a local maximum at 350°С are observed. Meanwhile, the saturation magnetization (M s ) for Fe 46 Co 35 Ni 19 nanoparticles increases with the increase of reducing temperature and the coercivity (H c ) decreases rapidly with a local minimum at 350°С. When the reducing time (tr) changes from 2-5 h, bcc phase is predominant in the Fe 46 Co 35 Ni 19 alloy particles. Both the particle size and M s have a maximum at tr = 3 h, and the H c reaches a maximum at tr = 4 h.

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