Cathodoluminescence evaluation of oxygen vacancy population in nanostructured titania thin films for photocatalytic applications.

Room-temperature results of cathodoluminescence (CL) spectroscopy investigations are presented for nanostructured titanium dioxide (anatase) thin films (500 nm thick) deposited via RF magnetron sputtering on high-purity silica substrates. The collected CL bands of the anatase thin films, as deposited and after different annealing cycles, showed a broad morphology consisting of three Voigtian bands located at 500, 550, and 610 nm that were partially overlapping. The overall CL emission increased with increasing temperature and time of the annealing cycle as a consequence of the increased crystallinity of the thin film. A clear trend was found for the oxygen-vacancy-related band (located at 610 nm), whose relative intensity decreased, as compared with the as-grown sample, after annealing in air; the higher the annealing temperature, the lower the relative intensity. We evaluated the photoactivity of the nanostructured thin film samples by measuring their photocatalytic activity in aqueous solution toward the degradation of phenol. A relationship between the decrease in oxygen vacancy concentration as a consequence of the annealing and the increase in the photoactivity was highlighted.

Histomorphometric, ultrastructural and microhardness evaluation of the osseointegration of a nanostructured titanium oxide coating by metal-organic chemical vapour deposition: an in vivo study.

Over the past decade the increase of elderly population has determined a rise in the incidence of bone fractures, and the improvement of the implant-bone interface remains an open problem. Metal-organic chemical vapour deposition (MOCVD) has recently been proposed as a technique to coat orthopaedic and dental prostheses with metal nanostructured oxide films either through the decomposition of oxygenated compounds (single-source precursors) or the reaction of oxygen-free metal compounds with oxygenating agents. The present study was performed to assess the in vivo biocompatibility of commercially pure Ti (control material: TI/MA) implants ( psi 2 mm x 5 mm length) coated with nanostructured TiO2 films by MOCVD (Ti/MOCVD) and then inserted into rabbit femoral cortical (middhiaphysis) and cancellous (distal epiphysis) bone. Histomorphometric, ultrastructural and microhardness investigations were carried out. Four and 12 weeks after surgery, significant (p<0.0005) increases in AI of Ti/MOCVD implants were observed as compared to Ti/MA implants (distal femoral epiphysis: 4 weeks=8.2%, ns; 12 weeks=52.3%, p <0.005; femoral diaphysis: 4 weeks=20.2%, p <0.0005; 12 weeks=10.7%, p <0.005). Bone microhardness results showed significant increases for the Ti/MOCVD versus Ti/MA implants at 200 microm in the femoral diaphysis (4 weeks=14.2, p <0.005) and distal femoral epiphysis (12 weeks=14.5, p <0.01) at 4 and 12 weeks, respectively. In conclusion, the current findings demonstrate that the nanostructured TiO2 coating positively affects the osseointegration rate of commercially pure Ti implants and the bone mineralization at the bone-biomaterial interface in both cortical and cancellous bone.

Secondary ion mass spectrometry and X-ray photoelectron spectroscopy investigation on chemical vapor deposited CeO(2-)ZrO(2)-TiO(2) thin films.

Mixed CeO(2)-ZrO(2) systems have attracted widespread interest for their use in three-way catalyst (TWC) technology for automotive exhaust conversion to non-toxic products. In this work, CeO(2)-ZrO(2) thin films were deposited, via chemical vapor deposition, in order to obtain nanoscale materials with a high surface-to-volume ratio, with precise control of system properties. The addition of TiO(2) as buffer layer was also investigated. Cordierite was chosen as substrate, being the usual refractory material for catalytic mufflers. The multilayers were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). In particular, the combination of SIMS and XPS allowed us to investigate both surface and in-depth chemical composition, studying also film-intermixing phenomena induced by annealing processes.