Materials characterization of TiO nanotubes decorated by Au nanoparticles for photoelectrochemical applications.

The structural and chemical modification of TiO nanotubes (NTs) by the deposition of a well-controlled Au deposit was investigated using a combination of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Scanning Transmission Electron Microscopy (STEM), Raman measurements, UV-Vis spectroscopy and photoelectrochemical investigations. The fabrication of the materials focused on two important factors: the deposition of Au nanoparticles (NPs) in UHV (ultra high vacuum) conditions (1-2 × 10 mbar) on TiO nanotubes (NTs) having a diameter of ∼110 nm, and modifying the electronic interaction between the TiO NTs and Au nanoparticles (NPs) with an average diameter of about 5 nm through the synergistic effects of SMSI (Strong Metal Support Interaction) and LSPR (Local Surface Plasmon Resonance). Due to the formation of unique places in the form of "hot spots", the proposed nanostructures proved to be photoactive in the UV-Vis range, where a characteristic gold plasmonic peak was observed at a wavelength of 580 nm.

TiO Nanotubes with Pt and Pd Nanoparticles as Catalysts for Electro-Oxidation of Formic Acid.

In the present work, the magnetron sputtering technique was used to prepare new catalysts of formic acid electrooxidation based on TiO nanotubes decorated with Pt (platinum), Pd (palladium) or Pd + Pt nanoparticles. TiO nanotubes (TiO NTs) with strictly defined geometry were produced by anodization of Ti foil and Ti mesh in a mixture of glycerol and water with ammonium fluoride electrolyte. The above mentioned catalytically active metal nanoparticles (NPs) were located mainly on the top of the TiO NTs, forming 'rings' and agglomerates.

Effect of Pt Deposits on TiO Electrocatalytic Activity Highlighted by Electron Tomography.

Characterizing materials at small scales presents major challenges in the engineering of nanocomposite materials having a high specific surface area. Here, we show the application of electron tomography to describe the three-dimensional structure of highly ordered TiO nanotube arrays modified with Pt nanoparticles. The titanium oxide nanotubes were prepared by the electrochemical anodization of a Ti substrate after which Pt was deposited by magnetron sputtering.

An electron microscopy three-dimensional characterization of titania nanotubes.

To characterize complex, three-dimensional nanostructures, modern microscopy techniques are needed, such as electron tomography and focused ion beam (FIB) sectioning. The aim of this study was to apply these two techniques to characterize TiO nanotubes in terms of their size, shape, volume, porosity, geometric surface area, and specific surface area (SSA). For these experiments, titania nanotubes were fabricated by means of the electrochemical oxidation of titanium at a voltage of 20 V for 2 hr followed by heat treatment at 450°C for 3 hr to change the amorphous structure into a crystalline anatase structure.

Metal TiO Nanotube Layers for the Treatment of Dental Implant Infections.

Titanium oxide nanotube layers with silver and zinc nanoparticles are attracting increasing attention in the design of bone and dental implants due to their antimicrobial potential and their ability to control host cell adhesion, growth, and differentiation. However, recent reports indicate that the etiology of dental infections is more complex than has been previously considered. Therefore, the antimicrobial potential of dental implants should be evaluated against at least several different microorganisms cooperating in human mouth colonization.

WC-β-SiC Nanocomposite Catalysts Used in Aqueous Phase Hydrogenation of Furfural.

This study investigates the effects of the addition of tungsten on the structure, phase composition, textural properties and activities of β-SiC-based catalysts in the aqueous phase hydrogenation of furfural. Carbothermal reduction of SiO₂ in the presence of WO₃ at 1550 °C in argon resulted in the formation of WC-β-SiC nanocomposite powders with significant variations in particle morphology and content of WC-tipped β-SiC nano-whiskers, as revealed by TEM and SEM-EDS. The specific surface area (SSA) of the nanocomposite strongly depended on the amount of tungsten and had a notable impact on its catalytic properties for the production of furfuryl alcohol (FA) and tetrahydrofurfuryl alcohol (THFA).

Microstructure of Haynes 282 Superalloy after Vacuum Induction Melting and Investment Casting of Thin-Walled Components.

The aim of this work was to characterize the microstructure of the as-cast Haynes 282 alloy. Observations and analyses were carried out using techniques such as X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray spectroscopy (EDS), wave length dispersive X-ray spectroscopy (WDS), auger electron spectroscopy (AES) and electron energy-loss spectrometry (EELS). The phases identified in the as-cast alloy include: γ (gamma matrix), γ' (matrix strengthening phase), (TiMoCr)C (primary carbide), TiN (primary nitride), σ (sigma-TCP phase), (TiMo)₂SC (carbosulphide) and a lamellar constituent consisting of molybdenum and chromium rich secondary carbide phase together with γ phase.

Surface characterization of Ca-P/Ag/TiO2 nanotube composite layers on Ti intended for biomedical applications.

The new generation of medical implants made by titanium is functionalized with different coatings to improve their bioactivity and reduce a risk of infection. This article describes how these goals can be achieved via deposition of silver nanoparticles and calcium phosphate coating. TiO(2) nanotubes were grown on a Ti substrate via electrochemical oxidation at constant voltage in a mixture of glycerol, deionized water, and NH(4) F.

Multiscale characterization of nanostructured Al-Si-Zr alloys obtained by rapid solidification method.

Properties of engineering metallic alloys (e.g., fracture toughness, corrosion resistance) are often limited by the presence of primary intermetallic particles which form during conventional solidification.