Cobalt microspheres constructed by the assembly of nanoplatelets have been synthesized by awet chemical reductive procedure at room temperature with the help of glycerin and citric acid and without additional surfactants. The size of the microspheres is about 2–5 mand that of the nanoplatelets assembled the microspheres is tens of nanometers in thickness. In this synthetic system, cobalt acetate was employed as Co source, sodium hydroxide was used to manipulate the pH value of the reaction system, and hydrazine hydratewas used as a reducing agent. A series of experimentswere performed with different amounts of glycerin, from 0.5mL to 4 mL, the results reveal that the formation of cobalt microspheres is assisted by glycerin. The shape, structure, and magnetic properties of the final products were invstigated by XRD, SEM and VSM. This kind of Co nanostructures shows a ferromagnetic behavior at room temperature with enhanced coercivity, and has potential uses in magnetic recording devices and other related nanodevices. A possible mechanism for the formation of microspheres is proposed.

Stabilized bismuth nanoparticles have been prepared by reducing bismuth chloride with hydrazine hydrate in the presence of sodium oleate under a facile water-based process. The obtained samples are investigated by X-ray diffraction, transmission electron microscopy (TEM) and differential thermal analysis and thermogravimetry (DTA/TG). The present results indicate that the bismuth nanoparticles are spherical, small diameter and in a high purity. In addition, measurement of water contact angle indicates that Bi samples are hydrophobic, which gives defense to samples from further oxidation, samples are steady in 6 months without obvious oxidation.

Copper nanoparticles (CuNPs) encapsulated by polymeric stabilizer of polyvinylpyrrolidone (PVP) (noted as PVPCuNPs) were simply prepared and used to construct an enzymeless glucose sensor on a solid substrate.Sensing and assay performance of the CuNPs-based sensor to glucose were evaluated in detail.Cyclic voltammetry (CV), chronoamperometry (I-t) and flow injection amperometry (FIA) revealed a high sensitivity, excellent stability, and good reproducibility in the glucose determination at ?0.45 V, which was 200 mV more negative than those in former reports.A detection limit as low as 1.0×10-8 M (signal-to-noise?3) and a linear range of 1.0×10-7 M to 5.0×10-3 M were obtained in this study.