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We report a spontaneous phase transformation of titania nanotubes induced by water at room temperature, which enables the as-anodized amorphous nanotubes to be crystallized into anatase mesoporous nanowires without any other post-treatments. These mesoporous TiO(2) nanomaterials have a markedly improved surface area, about 5.5 times than that of the as-anodized TiO(2) nanotubes, resulting in a pronounced enhanced photocatalytic activity. The present approach not only allows a flexible control over the morphology of TiO(2) nanostructures but can fundamentally eliminate the need for high temperature operations for crystallizing amorphous TiO(2).

This work reports an unexpected oxidation behavior of Cu nanoparticles embedded in porous Al(2)O(3) confinements that are produced by annealing alucone (an organic-inorganic hybrid material) deposited by molecular layer deposition. An oxidation of such encapsulated Cu nanoparticles by annealing in air produces Cu oxide nanoparticles attached to the outer surface of the hollow Al(2)O(3) nanostructures, which is in strong contrast to bare or compact, nonporous Al(2)O(3)-coated Cu nanoparticles, which result in hollow oxide nanospheres or do not undergo oxidation, respectively. The conversion from encapsulated Cu to supported oxide nanoparticles is explained by a concerted pore-assisted diffusion and oxidation mechanism. The micropores in the films, having diameters of several angstroms, permit a selective out-diffusion of Cu atoms and prevent the inward diffusion of oxygen. The subsequent oxidation occurs at the pore entrances, which work as multiple nucleation sites for the formation of oxide nanoparticles with a small size and good dispersion.

The great potential for medical applications of inorganic nanoparticles in living organisms is severely restricted by the concern that nanoparticles can harmfully interact with biological systems, such as lipid membranes or cell proteins. To enable an uptake of such nanoparticles by cells without harming their membranes, platinum nanoparticles were synthesized within cavities of hollow protein nanospheres (apoferritin). In vitro, the protein-platinum nanoparticles show good catalytic efficiency and long-term stability. Subsequently the particles were tested after ferritin-receptor-mediated incorporation in human intestinal Caco-2 cells. Upon externally induced stress, for example, with hydrogen peroxide, the oxygen species in the cells decreased and the viability of the cells increased.

Nanoporous Pt-Co alloy nanowires were synthesized by electrodeposition of Co-rich Pt(1)Co(99) alloy into anodic aluminum oxide (AAO) membranes, followed by a dealloying treatment in a mild acidic medium. These nanowires consist of porous skeletons with tiny pores of 1-5 nm and crystalline ligaments of 2-8 nm. Morphological and compositional evolutions of the porous Pt-Co nanowires upon dealloying were investigated, and their formation mechanism is discussed. The nanoporous Pt-Co alloy nanowires are found to exhibit distinctly enhanced electrocatalytic activities toward methanol oxidation as compared to the current state-of-the-art Pt/C and PtCo/C catalysts, thus showing substantial promise as efficient anode electrocatalysts in direct methanol fuel cells.