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Papers by Alessandra Sanson

Applied Surface Science, 2015

ABSTRACT The direct in-situ stabilization of an anatase-based nanocrystalline photocatalyst (Degu... more ABSTRACT The direct in-situ stabilization of an anatase-based nanocrystalline photocatalyst (Degussa P25) was obtained by sintering the catalyst powder in presence of Zr4+ organic salts. This approach allows the doping of an already-formed nanocrystalline photocatalyst instead of introducing the dopant in the crystal lattice during the catalyst synthesis. The procedure was demonstrated by the production of thick ceramic layers using the screen printing technique. This new method allows to easily stabilize the anatase phase 200 °C higher than the undoped P25 maintaining the same photocatalytic activity. The process was studied using specifically formulated screen-printing inks added with Zr4+ organic salt at 1% and 2% Zr/Ti molar ratio. The anatase phase stability was investigated in the 500-900 °C temperature range analysing the resulting catalysts with XRD, TEM and (S)TEM-EDS. The catalytic activity of the screen-printed layers was assessed by measuring the degradation of toluene in air at ambient concentration (500 nmol m−3) and low UV-A irradiance (180 μW cm−2). The described in-situ stabilization method could be potentially applied to any deposition process involving already formed anatase photocatalyst, allowing higher sintering temperature and then an improved mechanical stability of the active layers without photocatalytic activity degradation.

ECS Transactions, 2013

ABSTRACT The production of planar, anode-supported half-cell with suitable morphological characte... more ABSTRACT The production of planar, anode-supported half-cell with suitable morphological characteristics needs a careful control of the thermal treatments involved. Although the thermal profiles are generally well analyzed in literature, the role played by the setter plates on the half-cell manufacturing is generally neglected although they can strongly affect the final results. In this study, the influence of the nature of setter plates in the production of large area NiO- YSZ/YSZ half cells was deeply investigated. In particular, the performance and the possible interaction of the SiC, alumina and zirconia setter plates with the half-cell during the sintering stage were thoroughly evaluated in order to assess the best thermal setup

Conference code: 67292, Export Date: 25 March 2013, Source: Scopus, Language of Original Document... more Conference code: 67292, Export Date: 25 March 2013, Source: Scopus, Language of Original Document: English, Correspondence Address: Fabrizio, M.; CNR, IENIItaly, Sponsors: ENEA; Condiglio Nazionale Delle Ricerche; University of Perugia; Rolls-Royce; Ansaldo Fuel Cells

Diffusion and Defect Data Pt.B: Solid State Phenomena, 2011

International Journal of Hydrogen Energy, 2012

ABSTRACT Tape casting is a widely used ceramic process that generally makes use of pore former ag... more ABSTRACT Tape casting is a widely used ceramic process that generally makes use of pore former agents to produce elements with engineered porosity for SOFC applications. In this work, porous La0.8Sr0.2MnO3−δ-Ce0.8Gd0.2O2−δ (LSM-GDC) supporting cathode of suitable porosity was produced using the reactive sintering approach without using of pore forming agent. The reactive sintering approach was considered in order to exploit the porosity induced by the precursor decomposition during a single thermal treatment of calcining-debonding-sintering. A stable tape casting slurry of lanthanum, strontium and manganite precursors and GDC powder was used in order to obtain large-area, crack-free green tapes. This process allowed to obtain 10 × 10 cm2 LSM-GDC sintered tapes of thickness 600 μm with values of porosity and mechanical strength suitable for fuel cells applications, starting from the precursor mixture without the addition of pore former and avoiding any calcination step. Preliminary results show that the same conditions can be used to produce a LSM-GDC/GDC half-cell by co-firing this tape with on the top a screen-printed GDC layer. To the author knowledge this is the first time that the reactive sintering approach has been used to produce a large-area supporting cathode suitable for SOFC applications.

Journal of the European Ceramic Society, 2013

International Journal of Applied Ceramic Technology, 2012

ABSTRACT Nanostructured films of TiO2 are becoming more and more attractive as a consequence of t... more ABSTRACT Nanostructured films of TiO2 are becoming more and more attractive as a consequence of their improved sensing properties. Screen printing represents an important low-cost alternative for the production of high-performance devices for the automotive industry. However, to obtain films with superior properties, the composition and each step of the ink production must be carefully controlled. Milling strongly influences the rheological properties of the ink and, as a consequence, the quality of the deposited film. The as-prepared ink was homogenized in a four steps-process with a three-roll mill, and the rheological properties at each intermediate stage were measured. The results showed the dramatic effect of the milling on the flow properties of the nanoink and suggested the importance of a careful control of this step. The rheological behavior of the inks was explained using the basic idea of the transient network theory (TNT) for physically cross-linked networks of polymer solutions. Only an optimized cycle of milling can assure the necessary reproducibility of the ink properties as well as their time stability.

Metal-supported solid oxide fuel cell (MS-SOFC) provides significant advantages over conventional... more Metal-supported solid oxide fuel cell (MS-SOFC) provides significant advantages over conventional ceramic including reduction in cost, ruggedness, and tolerance to rapid thermal and redox cycling. Many materials have been recently investigated as metal supports for SOFC and are typically either nickel or iron based. In particular, ferritic stainless steels have received significant interest due to their low cost and the thermal compatibility with YSZ and CGO electrolyte materials. In order to improve the mechanical strength and the creep resistance of the stainless steel trace levels of Mo, Ti and Y2O3 are generally added to the metal composition. Particularly the addition of Al can improve the oxidation resistance by forming an Al2O3 scale at the surface of the metal that dramatically increases the lifetime of the cell at temperatures below 650°C. Despite the recent progresses in the MS-SOFC production however, the power density of these cells remained mediocre compared to the anod...

Ceramics International, 2015

ABSTRACT In this study, a novel procedure for the production of Zr-doped TiO2 ceramic layers, dep... more ABSTRACT In this study, a novel procedure for the production of Zr-doped TiO2 ceramic layers, deposited by screen-printing technique, is presented. A suitable Zr precursor (Zr(IV) 2,4-pentanedionate) was added to the formulation of a standard TiO2 ink, in order to promote the diffusion of Zr ions directly during the sintering of the deposited layers. In order to evaluate the impact of this process on the properties of the ink, thermal and rheological analysis were done; a significant effect on the flow behavior was found, related to a relevant dispersing action of the precursor. The efficacy of the method was proved by XRD analyses, that showed the stabilization of anatase phase and crystal size at high temperature (700 °C), due to Zr doping. The properties of the films were then analyzed in order to evaluate their application as photoanodes for Dye-Sensitized Solar Cells (DSCs). The use of the Zr precursor resulted to improve the film morphology, whereas it did not affect the dye adsorption capability of the TiO2. Electrochemical characterization pointed out increased flat band potential and density of states (DOS), the latter being potentially beneficial even for photocatalytic applications. Doped photoanodes resulted to induce a slight deterioration of the performance, pointing out the need of a more accurate optimization of the process for this application. Finally, the proposed doping method resulted effective and potentially adaptable to other dopant-semiconductor systems.

Sensors and Microsystems - Proceedings of the 13th Italian Conference, 2009