Zhude Xu

Carbon nanotubes coated with tubular MoS2 layers prepared by hydrothermal reaction

Carbon nanotubes (CNTs) coated with MoS2 were produced by hydrothermal reaction using Na2MoO4 as the Mo source and CS(NH2)2 as the reducing agent and S source, with CNTs present. The product was characterized by high resolution transmission electron microscopy, energy-dispersive spectroscopy, Raman and x-ray diffraction methods. The effects of CNTs on the formation of the tubular MoS2 layers were discussed. It was found that CNTs provide a topological and structural template favouring nucleation and growth of tubular MoS2 layers on the surface of CNTs. The tubular MoS2 layers had a high crystallinity. Heteronanostructural MoS2/CNTs composite nanotubes could be obtained in this facile way.

Cyclohexanol dehydrogenation over Co/carbon nanotube catalysts and the effect of promoter K on performance

Carbon nanotubes (CNT) were used as support medium to prepare Co catalysts for the selective dehydrogenation of cyclohexanol. Due to the unique structure and electronic property of CNT, Co/CNT possessed less acid sites than Co/activated carbon (AC). It seems to be easier to form multi-point complexes on Co/CNT than on Co/AC, resulting in a little higher selectivity to cyclohexanone and different distribution of by-products. The effect of K addition, attributed to electronic promotion, was also stronger on Co–K/CNT than on Co–K/AC.

A simple method for coating carbon nanotubes with Co–B amorphous alloy

A simple chemical method was employed to coat carbon nanotubes (CNTs) with a layer of Co-B amorphous alloy. This technique involved a redox reaction using KBH4 as reducing agent and Na-2[Co(OH)(4)] complex as cobalt precursor. The amorphous character of the Co-B alloy was confirmed by high-resolution transmission electron microscopy (HRTEM) and Xray diffractogram analysis (XRD). These coated carbon nanotubes may be of great interest in magnetic research and as highly active catalysts in heterogeneous catalysis

Co/carbon-nanotube monometallic system: the effects of oxidation by nitric acid

Multi-walled carbon nanotubes, produced from catalytic decomposition of C2H2, were pre-oxidized by boiling nitric acid before being used as support media in a Co/carbon-nanotube monometallic catalyst system. The microstructures of nanotubes and the cobalt particles were examined by using high-resolution transmission electron microscopy and X-ray diffractometry. Various structural modifications on the nanotubes, such as thinned tubes, tubes with holes, and stepped surface with open edges of graphitic sheets were observed. In comparison with cobalt particles on unoxidized nanotubes, the cobalt nanoparticles deposited on the oxidized nanotubes have much smaller size and higher dispersion, resulting in significantly better catalytic performance (18.4% higher in initial conversion) in dehydrogenation of cyclohexanol to cyclohexanone.

Controlled Synthesis of Carbon-Encapsulated Co Nanoparticles by CVD

Communication: Carbon-encapsulated cobalt nanoparticles are prepared over a range of temperatures and partial pressures by CVD from cyclohexane on prepared substrates consisting of ground powders Of SiO2 impregnated with Co(NO3)(2) and (NH4)(2)Mo2O7. The encapsulated cobalt nanoparticles are freed from the incorporated SiO2 and molybdenum by treating the deposition product with aqueous hydrofluoric acid. Extracted material is dispersed in ethanol and deposited on a carbon-coated and prior to investigation by high-resolution TEM.

Synthesis and superconductivity of a new type of 1212 phase cuprates (B, Cd) (Sr, Ba) 2YCu2Oy

Abstract A new type of 1212 phase cuprates (B, Cd)Sr 2 YCu 2 O y has been synthesized by solid-state reaction. In the (B 0.5 Cd 0.5 )Sr 2 − x Ba x YCu 2 O y system, Ba substituting induces superconductivity, with the optimum T c of 60 K for x = 0.6. The nonmonotonic variation of T c with Ba content is discussed.