Lihong Dong

Controllable Synthesis of Nickel Hydroxide and Porous Nickel Oxide Nanostructures with Different Morphologies

Alpha-Ni(OH)(2) nanobelts, nanowires, short nanowires, and beta-Ni(OH)(2) nanoplates have been successfully prepared in high yields and purities by a convenient hydrothermal method under mild conditions from very simple systems composed only of NaOH, NiSO(4), and water. It has been found that the ratio of NaOH to NiSO(4) not only affects the morphology of the Ni(OH)(2) nanostructures, but also determines whether the product is of the alpha- or beta-crystal phase. A notable finding is that porous NiO nanobelts were produced after exposure of the Ni(OH)(2) products to an electron beam for several minutes during transmission electron microscopy (TEM) observations. Another unusual feature is that rectangular nanoplates with many gaps were obtained. Furthermore, porous NiO nanobelts, nanowires, and nanoplates could also be obtained by annealing the as-prepared Ni(OH)(2) products. A sequence of dissolution, recrystallization, and oriented attachment-assisted self-assembly of nanowires into nanobelts is proposed as a plausible mechanistic interpretation for the formation of the observed structures. The method presented here possesses several advantages, including high yields, high purities, low cost, and environmental benignity. It might feasibly be scaled-up for industrial mass production.

In situ synthesis and assembly of copper oxide nanocrystals on copper foil via a mild hydrothermal process

Different dimensional cupric oxide (CuO) nanocrystals and their architectures have been prepared on copper foil via a mild hydrothermal process with the introduction of different types of surfactants. The X-ray powder diffraction (XRD) and energy dispersive X-ray (EDX) patterns indicate that the products are pure CuO and of monoclinic symmetry. Furthermore, the selected area electron diffraction (SAED) pattern and high-resolution transmission electron microscope (HRTEM) reveal that the products are single-crystalline in nature. Series of experiments confirm that the type of surfactant, the concentration of the surfactant, the concentration of the reactants and the reaction temperature play important roles in the morphology and nanoarchitecture of the products.

One-step synthesis and properties of urchin-like PS/α-Fe2O3 composite hollow microspheres

A new progressive hard template method has been developed to synthesize uniform polystyrene (PS)/α-Fe2O3 composite hollow microspheres under hydrothermal conditions. Sulfonated polystyrene (PS) microspheres were used as templates as well as the endothecia of the composite microspheres; Fe2O3 shell was obtained through the reaction of FeSO4 and KClO3 under hydrothermal conditions. Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) studies showed that the as-obtained products consist of large scale monodisperse urchin-like hollow microspheres. In comparison with the Fe2O3 of other structures, the composite hollow microspheres have good photocatalytic activity, large surface area and a high remanent magnetization. A possible mechanism for the formation of composite hollow microspheres is also proposed in the paper.

Two-minute synthesis of PbS nanocubes with high yield and good dispersibility at room temperature

A novel water/glycerol/polyvinylpyrrolidone (PVP) ternary system is developed to realize the successful growth of PbS nanocubes with a narrow size distribution and sharp facets and edges using a one-step synthesis at room temperature for the first time. The synthesis is very fast, high yield, environment-friendly, and low cost. The product possesses uniform dimensionality, high crystallinity and better dispersibility. After dispersing the nanocubes in water or ethanol, the as-formed colloidal suspensions can maintain excellent stability for more than one year under ambient conditions. Uniform silica layers were successfully coated onto the nanocubes via a modified Stöber method to enhance their performance for promising applications. Moreover, by soaking the as-prepared PbS/SiO(2) core-shell nanocubes in hydrochloric acid aqueous solution, well-resolved cubic SiO(2) nanoboxes were obtained. The formation mechanism and the reason for the better dispersibility and excellent stability of the as-obtained nanocubes are also discussed rationally.