The increasing need for new materials capable of solar fuel generation is central in the development of a green energy economy. In this contribution, we demonstrate that black TiO(2) nanoparticles obtained through a one-step reduction/crystallization process exhibit a bandgap of only 1.85 eV, which matches well with visible light absorption. The electronic structure of black TiO(2) nanoparticles is determined by the unique crystalline and defective core/disordered shell morphology. We introduce new insights that will be useful for the design of nanostructured photocatalysts for energy applications.

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This Full Paper investigates the adsorption and desorption of the anticancer drugs cis‐diamminedichloroplatinum(II) (CDDP, cisplatin) and the new platinum(II) complex di(ethylenediamineplatinum)medronate (DPM), as well as the clinically relevant bisphosphonate alendronate, towards two biomimetic synthetic HA nanocrystalline materials with either plate‐shaped (HAps) or needle‐shaped (HAns) morphologies and different chemico‐physical properties. The adsorption and desorption kinetics are dependent on the specific properties of the drugs and the morphology of the HA nanoparticles. Adsorption of the platinum complexes occurs with retention of the nitrogen ligands but the chloride ligands of cisplatin are displaced. Despite their opposite charges, the negatively charged alendronate bisphosphonate and the positively charged aquated cisplatin are strongly adsorbed, while the neutral DPM complex shows lower affinity towards the negatively charged apatitic surface. The data suggest that adsorption of the two platinum complexes is driven by electrostatic attractions, while interaction between the alendronate and the HA surface takes place by ligand exchange in which the two phosphonate groups of the drug molecule replace two surface phosphate groups. Significantly, adsorption of positively charged hydrolysis species of cisplatin is more favored on the phosphate‐rich HAns surface while adsorption of negatively charged alendronate is more favored on the calcium‐rich HAps surface. The latter type of short‐range electrostatic interactions also appear to dominate the desorption kinetics; consequently, drug release is greater for neutral DPM than for charged alendronate and aquated cisplatin. Moreover, while the release per unit area of charged species is the same for the two types of HAs, the release of DPM is faster from HAns, which is lower in surface calcium, than for HAps. Overall, this work demonstrates that the properties of HA nanocrystals can be modulated in such a way to produce HA/biomolecule conjugates tailored for specific therapeutic applications.

Nitrogen-doped TiO 2 materials were successfully prepared following three different preparation routes (sol-gel, mechanochemistry, and oxidation of TiN) and characterized by X-ray diffraction, electron microscopy, and various spectroscopic techniques. All samples absorb visible light, and the one obtained via sol-gel, showing the anatase structure, is the most active in the decomposition of organic compounds under visible light. Various nitrogen-containing species have been observed in the materials, whose presence and abundances depends on the preparative route. Ammonium NH 4 + ions are residual of the synthesis using ammonium salts (sol-gel, mechanochemistry) and are quite easily eliminated, as shown by the parallel behavior of both NMR and XPS spectra. Cyanide CNions form at high temperature in parallel with the phase transition of the solid to rutile. Molecular nitric oxide forms in the case of materials exhibiting close porosity. The already reported bulk radical species, N b • , is the only paramagnetic center observed in all types of samples, and is responsible for the visible light sensitization of TiO 2 . A mechanism for the formation of such a species in chemically prepared N-doped TiO 2 materials is for the first time proposed based on the reduction of Nitric Oxide (NO) at oxygen vacancies

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A new method for altered enamel surface remineralization has been proposed . To this aim carbonate-hydroxyapatite nanocrystals which mimic for composition, structure, nanodimensions, and morphology dentine apatite crystals and resemble closely natural apatite chemical-physical properties have been used The results underline the differences induced by the use of fluoride ions and hydroxyapatite nanocrystals in contrasting the mechanical abrasions and acid attacks to which tooth enamel is exposed. Fluoride ions generate a surface modification of the natural enamel apatite crystals increasing their crystallinity degree and relative mechanical and acid resistance. On the other hand, the remineralization produced by carbonate-hydroxyapatite consists in a deposition of a new apatitic mineral into the eroded enamel surface scratches. A new biomimetic mineral coating, which progressively fills and shadows surface scratches, covers and safeguards the enamel structure by contrasting the acid and bacteria attacks.

The effect of preparation method (deposition-precipitation versus sol immobilisation method) and reduction method (calcination versus chemical reduction) on Au/TiO 2 catalysts for the liquid phase oxidation of glycerol has been studied. It was revealed that a different trend existed in terms of activity and distribution of products. The catalytic activity is shown to be dependent not only on the choice of the reduction method but also on the use of protective agent (PVA, THPC) for the stabilization of the gold colloids. In fact, the highest activity was found when a low temperature chemical reduction was employed on a Au/TiO 2 sample synthesised by the deposition-precipitation method. The use of a higher pre-treatment temperature or of a protective agent resulted in a lower activity but could be used to direct selectivity in oxidation reactions. The structural data (HRTEM and XPS) along with the catalytic results indicate that the combination of metallic Au 0 species with small particle size (2-5 nm) are responsible for the high activity observed in the liquid phase oxidation of glycerol. #