Transition metal-based amorphous alloys have attracted increasing attention as precious-metal-free electrocatalysts for oxygen evolution reaction (OER) of water splitting due to their high macro-conductivity and abundant surface active sites. However,...

In this study, AB-type carbonated hydroxyapatite (CHAp) nanosheet-assembled hollow microstructures were rapidly synthesized via a hydrothermal process without sintering. Urea was employed as both a pH adjusting agent and a CO 3 2− source during hydrothermal reaction. The influence of hydrothermal time on the final morphologies of the products was systematically investigated. The as-prepared CHAp hollow microstructures with a diameter of about 3-4 μm consist of numerous radially oriented CHAp nanosheets as building units with an average thickness of about 10 nm. The morphology of the product can vary from a hollow microstructure to a solid dandelion-like structure with increasing hydrothermal time. Possible mechanisms for the formation of a nanosheet-assembled CHAp hollow microstructure and a solid dandelion-like microstructure in the presence of both urea and ethylenediaminetetraacetic acid (EDTA) are illustrated. Moreover, the as-prepared CHAp hollow microstructures exhibit a high drug loading capacity and sustained drug release properties.

Highly ordered hierarchical TiO2 nanostructures involving primary honeycomb and secondary nanoparticles and nanowires are prepared by a two-step facile process. The TiO2 nanotube arrays grow first on Ti foil through anodization. After the wet-chemical reaction of the TiO2 nanotube arrays with alkaline and acid solution in turn, the hierarchical nanostructures wire-in-honeycomb and porous honeycomb are obtained by a dissolution-coagulation and dissolution-adsorption mechanism, respectively. The power conversion efficiency of the hierarchical TiO2 honeycomb nanostructures for the dye-sensitized solar cells (DSCs) shows a significant improvement, as high as 5.73%, increased by 1.42 times compared with that of TiO2 nanotube arrays. The performance improvement of DSCs based on the hierarchical nanostructures is attributed to the increase in the specific surface area.

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