One-dimensional arrays of Co 3 O 4 nanoparticles were obtained via the thermal treatment of cobalt oxalate nanorods, which were synthesized through a convenient solvothermal route. The optical properties of Co 3 O 4 nanoparticles were investigated. The optical absorption spectrum indicates that the direct band gaps of Co 3 O 4 nanoparticles are 1.52 and 2.01 eV. The galvanostatic experiment shows the excellent electrochemical performance between 3.0 and 0.2 V.

b-FeOOH nanorods with a tunnel-type structure were synthesized via a hydrothermal method at low temperature and characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA) and galvanostatic tests. From TEM bright-field images, a rodlike morphology with an average diameter of 30 ¡ 5 nm and an average length of 400 nm (aspect ratio # 13) is observed. Electrochemical tests show that thesew nanorods deliver a large discharge capacity of 275 mA h g 21 vs. Li metal at 0.1 mA cm 22 (voltage window 1.5-4.2 V). a-Fe 2 O 3 nanorods with a regular pore structure were obtained by calcining the as-synthesized FeOOH at 520 uC.

Anionic surfactant-AOT-microemulsions-assisted formation and evolution of PbWO4 nanostructures with bundles rodlike, ellipsoidlike, and spherelike prepared at different media conditions were studied by powder X-ray diffraction pattern, field emission scanning electron microscopy, and transmission electron microscopy. The possible mechanisms for the formation of PbWO4 samples in series of microemulsion systems were discussed. Various comparison experiments show that several experimental parameters, such as the AOT concentration, the water content, and reaction temperature play important roles in the morphological control of PbWO4 nanostructures. Room-temperature photoluminescence of PbWO4 samples with different morphologies has also been investigated and the results reveal that all these samples showed similar features with emissions at 480 ∼ 510 nm but different luminescence intensity.

Nickel oxide nanoparticles with an average diameter of about 9 nm were synthesized via thermal decomposition of NiC2O4 precursor at 450 °C. The nanoparticles were investigated using XRD, TEM, TGA, and UV–vis spectrophotometry. The optical absorption spectrum indicates that the NiO nanoparticles have a direct band gap of 3.56 eV. The electrochemical tests show that the ultrafine NiO nanoparticles, as a promising electrode material, can deliver a large reversible discharge capacity of about 610 mA h g−1.