Insights into the Plasma-Assisted Fabrication and Nanoscopic Investigation of Tailored MnO Nanomaterials.

Among transition metal oxides, MnO is of considerable importance for various technological end-uses, from heterogeneous catalysis to gas sensing, owing to its structural flexibility and unique properties at the nanoscale. In this work, we demonstrate the successful fabrication of supported MnO nanomaterials by a catalyst-free, plasma-assisted process starting from a fluorinated manganese(II) molecular source in Ar/O plasmas. A thorough multitechnique characterization aimed at the systematic investigation of material structure, chemical composition, and morphology revealed the formation of F-doped, oxygen-deficient, MnO-based nanomaterials, with a fluorine content tunable as a function of growth temperature ( T).

BiOCl/(BiO)CO Nanocomposite Materials for Pollutant Adsorption and Degradation: Modulation of the Functional Properties by Composition Tailoring.

BiOCl/(BiO)CO nanocomposite materials were studied as bifunctional systems for depuration of wastewater. They are able to efficiently adsorb and decompose rhodamine B (RhB) and methyl orange (MO), used as model pollutants. BiOCl/(BiO)CO nanocomposites were synthesized at room temperature and ambient pressure by means of controlled hydrolysis of BiCl in the presence of a surfactant (Brij 76).

Correlation between Deposition Parameters and Hydrogen Production in CuO Nanostructured Thin Films.

In this article, we report a systematic investigation of the role of (i) substrate temperature, (ii) oxygen partial pressure, and (iii) radio frequency (rf) power on the crystal structure and morphology of CuO nanostructured thin films prepared by means of rf-magnetron sputtering starting from a Cu metal target. On selected films, photocatalytic tests have been carried out in order to correlate the structural and morphological properties of the thin films prepared under different conditions with the photocatalytic properties and to find out the key parameters to optimize the CuO nanostructured films. All of the synthesized films were single-phase CuO nanorods of variable diameter between 80 and 200 nm.

Supported F-doped alpha-Fe2O3 nanomaterials: synthesis, characterization and photo-assisted H2 production.

Supported fluorine-doped alpha-Fe2O3 nanomaterials were synthesized by Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) at temperatures between 300 and 500 degrees C, using a fluorinated iron(II) diketonate-diamine compound as a single-source precursor for both Fe and F. The system structure, morphology and composition were thoroughly investigated by various characterization techniques, highlighting the possibility of controlling the fluorine doping level by varying the sole growth temperature. Photocatalytic H2 production from water/ethanol solutions under simulated solar irradiation evidenced promising gas evolution rates, candidating the present PE-CVD approach as a valuable strategy to fabricate highly active supported materials.

H₂ production by renewables photoreforming on Pt-Au/TiO₂ catalysts activated by reduction.

Bimetallic Pt-Au nanoparticles supported on reduced anatase nanocrystals represent a new class of promising photocatalysts with high activity in hydrogen production by photoreforming of aqueous solution of renewable feedstock, such as ethanol and glycerol. The catalysts are easily obtained by metal impregnation of commercial TiO₂, followed by a reductive treatment. Remarkably, deeper catalyst pre-reduction results in enhanced photoactivity.

F-Doped Co3O4 photocatalysts for sustainable H2 generation from water/ethanol.

p-Type Co(3)O(4) nanostructured films are synthesized by a plasma-assisted process and tested in the photocatalytic production of H(2) from water/ethanol solutions under both near-UV and solar irradiation. It is demonstrated that the introduction of fluorine into p-type Co(3)O(4) results in a remarkable performance improvement with respect to the corresponding undoped oxide, highlighting F-doped Co(3)O(4) films as highly promising systems for hydrogen generation. Notably, the obtained yields were among the best ever reported for similar semiconductor-based photocatalytic processes.

Embedded phases: a way to active and stable catalysts.

Industrial catalysts are typically made of nanosized metal particles, carried by a solid support. The extremely small size of the particles maximizes the surface area exposed to the reactant, leading to higher reactivity. Moreover, the higher the number of metal atoms in contact with the support, the better the catalyst performance.

CuO(x)-TiO2 photocatalysts for H2 production from ethanol and glycerol solutions.

Hydrogen production by photocatalytic reforming of aqueous solutions of ethanol and glycerol was studied with the use of impregnated and embedded CuO(x)/TiO(2) photocatalysts. Embedded CuO(x)@TiO(2) was prepared by a water-in-oil microemulsion method, which consists in the formation of Cu nanoparticles in the microemulsion followed by controlled hydrolysis and condensation of tetraisopropyl orthotitanate with the aim of covering the protected metal particles with a surrounding layer of porous titanium oxyhydroxide. Mild calcination leads to the complete removal of the organic residues, the crystallization of TiO(2), and an unavoidable oxidation of copper.

Photocatalytic decolourization of dyes on NiO-ZnO nano-composites.

NiO-ZnO nanocomposite photocatalysts were synthesized by co-precipitation/co-gel formation techniques using potassium hydroxide (KOH), sodium carbonate (Na(2)CO(3)) and oxalic acid (H(2)C(2)O(4)) as precipitating agents. X-Ray diffraction (XRD) analysis was employed for the determination of crystallite size and phase purity, while BET surface areas were estimated by nitrogen physisorption analysis. The photocatalytic activities of the NiO-ZnO nanocomposites, evaluated using the photo-decolourization of two structurally different dyes, methyl orange and methylene blue, were correlated with the variation in the crystallite size of the constituents of the composites.

The potential of supported Cu2O and CuO nanosystems in photocatalytic H2 production.

Hy wire: Supported Cu(2)O nanosystems and CuO nanowires obtained by chemical vapor deposition were used in the photocatalytic splitting of methanol/water solutions to produce hydrogen. The results obtained with these systems open appealing perspectives for the clean conversion of sunlight into storable chemical energy.

Surface phases and photocatalytic activity correlation of Bi2O3/Bi2O4-x nanocomposite.

UV-visible irradiation induces surface alteration of Bi2O3 leading to Bi2O3/Bi2O4-x nanocomposites with excellent photocatalytic activity.