Pierluigi Antonucci

A comparison of the ethanol sensing properties of α-iron oxide nanostructures prepared via the sol–gel and electrospinning techniques

Haematite (α-Fe2O3) nanostructures were synthesized via a Pechini sol-gel method (PSG) and an electrospinning (ES) technique. Their texture and morphology were investigated by scanning and transmission electron microscopy. α-Fe2O3 nanoparticles were obtained by the PSG method, whereas fibrous structures consisting of interconnected particles were synthesized through the ES technique. The crystallinity of the α-Fe2O3 nanostructures was also studied by means of x-ray diffraction and Raman spectroscopy. Gas-sensing devices were fabricated by printing the synthesized samples on ceramic substrates provided with interdigitated Pt electrodes. The sensors were tested towards low concentrations of ethanol in air in the temperature range (200-400 °C). The results show that the α-Fe2O3 nanostructures exhibit somewhat different gas-sensing properties and, interestingly, their sensing behaviour is strongly temperature-dependent. The availability of active sites for oxygen chemisorption and the diffusion of the analyte gas within the sensing layer structure are hypothesized to be the key factors responsible for the different sensing behaviour observed.

A Novel Anode Based on Ni-Modified Perovskite for Direct Alcohol Solid Oxide Fuel Cells

A Ni-modified La0.6Sr0.4Fe0.8Co0.2O3 / Ce0.9Gd0.1O2 catalyst was prepared by incipient wetness. The product thus obtained was calcined at 1100°C for 2 h in static air. After thermal activation, Ni was mainly present as highly dispersed La2NiO4 on the surface of perovskite surface. The thermal reduction at 800 °C caused the occurrence of metallic Ni on the surface. Surface area was determined by BET measurement. The catalyst was used as anode in IT-SOFCs fed with methanol. Studies under steam reforming, partial oxidation and autothermal reforming of methanol were carried out at 800°C. A comparison was made between the performance of SOFCs fed with syngas or methanol. The results with methanol are promising both in terms of energy density as well as suitable performance for portable power sources.

Preparation of PVA/ Sm(NO3)3-Sm2O3 Composites Nanofibers by Electrospinning Technique

. In this work PVA/Sm2O3 composite fibers and Sm2O3 fibers (PVA and Sm(NO3)3 were used as precursors) were prepared by using electrospinning technique. The fibers obtained were characterized by scanning electron microscopy, X-ray diffraction, thermogravimetric analysis and Fourier transform infrared spectroscopy.

Mixed semiconductor materials: Photoelectrochemical behavior of (TiNb)ox at the isoelectric point of the interface

Abstract The influence of the pH variation on the value of the flat-band potential (Vfb) and on the conversion efficiency in the photodecomposition of water has been investigated using (TiNb) oxide electrodes. The relationship between Vfb, and pH follows Nernsts law with the exception of a discontinuity point at the pH = zpc of the oxide system. At this particular pH value, Vfb reaches its most negative value and the conversion efficiency is maximum. The observations denote the existence of a particular situation at the semiconductor-electrolyte interface in the absence of the Helmholtz layer. On the basis of the cyclic voltammetry analysis, the resulting phenomenon is interpreted in terms of creation of particular surface states in combination with very rapid ion adsorption-desorption processes.

CO2 sensing properties of electro-spun Ca-doped ZnO fibres

The availability of low-cost, high-performing sensors for carbon dioxide detection in the environment may play a crucial role for reducing CO2 emissions and limiting global warming. In this study, calcium-doped zinc oxide nanofibres with different Ca to Zn loading ratios (1:40 or 1:20) are synthesised via electro-spinning, thoroughly characterised and, for the first time, tested as an active material for the detection of carbon dioxide. The results of their characterisation show that the highly porous fibres consist of interconnected grains of oxide with the hexagonal wurtzite structure of zincite. Depending on the Ca:Zn loading ratio, calcium fully or partly segregates to form calcite on the fibre surface. The high response of the sensor based on the fibres with the highest Ca-doping level can be attributed to the synergy between the fibre morphology and the basicity of Ca-ion sites, which favour the diffusion of the gas molecules within the sensing layer and the CO2 adsorption, respectively.