Developing Functionality in Perovskites from Abatement of Pollutants to Sustainable Energy Conversion and Storage

Different functionalities can be developed and optimised in perovskites by means of different approaches: doping, nanocomposition and exsolution. In our research, these strategies are used with the aim of a sustainable development. Our objectives are in developing perovskite-based materials for catalysis and electro-catalysis. In particular, we successfully obtained catalysts for abatement of pollutants in three-way catalysts, catalysts for dry reforming of methane and electro-catalysts for solid oxide cells (solid oxide fuel cells and solid oxide electrolysers). In all cases, the corresponding device and experimental set-up was optimised. The catalysts and electro-catalysts we considered are free of noble metals and with minimum amount of critical raw materials. The preparation procedures are by wet chemistry, highly reproducible and up-scalable

Reversible, all-perovskite SOFCs based on La, Sr gallates

In this contribution, a reversible Solid Oxide Cell based on perovskites was developed. La0.6Sr0.4Ga0.3Fe0.7O3 (LSGF) was chosen as electrode and deposited onto La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte. The cell was investigated from the morphological (SEM) and compatibility (XRD) point of view. Electrochemical investigation confirmed that the cell can operate in fuel cell and in electrolyser modes. Impregnation with CGO and Pd allowed a 15 times increment of the power density (until limit is the cell architecture). The same cell with an impregnated negative electrode was then tested in steam electrolysis mode in a non-reducing environment. The overall performance is slightly lower than state-of-the-art materials and comparable with similar perovskites, and in general is fair considering the needed cell optimization (i.e an anode supported configuration is necessary). The cell (impregnated and not) activates at 0.7 V. Obtained data suggest thus LSGF/LSGM/LSGF cell, is promising as reversible SOC for intermediate temperature.PostprintPeer reviewe

Amphiphilic modified-styrene copolymer films: Antifouling/fouling release properties against the green alga Ulva linza

Surface-active copolymers of a styrene carrying a polysiloxane side chain (SSi) and a triethyleneglycol monomethyl ether-modified pentafluorostyrene (EFS) (39 and 77 mol% EFS) were prepared and incorporated (8 wt% loading) into a polydimethyl siloxane (PDMS) matrix to produce crosslinked blend films. The wettability of the surface-active copolymer films and PDMS-blend films was investigated by contact angle measurements. An angle-resolved X-ray photoelectron spectroscopy (XPS) of the surface chemical composition before and after immersion in water for 7 days enabled location of the hydrophilic oxyethylenic segments of EFS within the top 10 nm from the film surface. Laboratory bioassays on the blend films against the marine green alga Ulva linza evidenced that the films containing the copolymer with the larger EFS content showed greater resistance to settlement of zoospores of U. linza, whereas both films had superior fouling-release properties of sporelings (young plants) compared to the PDMS standard films

Effect of the pH in the growth of benzotriazole model layers at realistic environmental conditions

A. M. acknowledges financial support from the Erasmus+ for Traineeship programme of the European Union - Academic Year 2014/2015.The growth of benzotriazole (BTAH) via solution deposition onto copper monolayers prepared via underpotential deposition (UPD) on Au(111)/mica substrates has been investigated using X-ray photoelectron spectroscopy (XPS) and ambient scanning tunnelling microscopy (STM) as a function of solution pH and immersion time. Adsorbed species have been found sensitive to the solution pH with a higher benzotriazole surface concentration following deposition from an acidic environment. Although the layers prepared at different pH are chemically different, as highlighted by XPS, similar morphologies are recorded via STM. These results are critically discussed in the light of some of the adsorption models previously reported.PostprintPeer reviewe

Nb3Sn Targets Synthesis via Liquid Tin Diffusion for Thin Films Depositions

The deposition of superconducting Nb3 Sn on copper accelerating cavities is interesting for the higher thermal conductivity of copper compared to common Nb substrates. The better heat exchange would allow the use of cryocoolers reducing cryogenic costs and the risk of thermal quench [1]. The magnetron sputtering technology allows the deposition of Nb 3 Sn on substrates different than Nb, however the coating of substrates with complex geometry (such as elliptical cavities) may require target with non-planar shape, which are difficult to realize with classic powder sintering techniques. In this work, the possibility of using the Liquid Tin Diffusion (LTD) technique to produce sputtering targets is explored. The LTD technique is a wire fabrication technology, already developed in the past at LNL for superconducting radio frequency (SRF) applications [2], that allows the deposition of very thick and uniform coating on Nb substrates even with complex geometries [3]. Improvements in LTD process, proof of concept of a single use LTD target production, and characterization of the Nb 3 Sn film coated by DC magnetron sputtering with these innovative targets are reported in this work

Novel Correlations between Spectroscopic and Morphological Properties of Activated Carbons from Waste Coffee Grounds

Massive quantities of spent coffee grounds (SCGs) are generated by users around the world. Different processes have been proposed for SCG valorization, including pyrolytic processes to achieve carbonaceous materials. Here, we report the preparation of activated carbons through pyrolytic processes carried out under different experimental conditions and in the presence of various porosity activators. Textural and chemical characterization of the obtained carbons have been achieved through Brunauer–Emmett–Teller (BET), ESEM, 13C solid state NMR, XPS, XRD, thermogravimetric and spectroscopic determinations. The aim of the paper is to relate these data to the preparation method, evaluating the correlation between the spectroscopic data and the physical and textural properties, also in comparison with the corresponding data obtained for three commercial activated carbons used in industrial adsorption processes. Some correlations have been observed between the Raman and XPS data

Surface behaviour of modified-polystirene triblock copolymers with different macromolecular architectures

We synthesized novel amphiphilic triblock copolymers of the ABC, ACB, ACD and ADC types composed of polystyrene (A), hydrophilic polyethylene glycol-modified polystyrene (B), hydrophobic/lipophilic polysiloxane-modified polystyrene (C) and hydrophobic/ lipophobic perfluoroalkyl-modified polystyrene (D) blocks. Surface domain morphology, chemical composition and wettability of the polymer films were investigated by atomic force microscopy (AFM), angle-resolved X-ray photoelectron spectroscopy (XPS) and contact angle analyses, respectively. Each analysis proved that the surface (nano)structure of the polymer films was strongly affected by the chemistry of the triblock copolymer and weakly depended on the sequential position of the blocks in the copolymer. The low surface energy component (C or D) populated the surface in any case. Contact angle and XPS measurements carried out on the films after six\u2013seven days of immersion in water showed that triblock copolymers containing the lowest surface energy fluoroalkyl block (D) underwent surface reconstruction to a greater extent than those possessing the polysiloxane block (C)

The reactivity of a Fe-Ti-O mixed oxide under different atmosphere: study of the interaction with simple alcohol molecules

In this paper, the interaction between simple alcohols(methanol to 1-butanol ) and a Fe\u2013Ti mixed oxide was investigated. The reactivity of the mixed system was studied both at atmospheric pressure and in vacuum conditions and compared with that of the pure oxides (TiO2and Fe2O3). To understand the influence of the oxygen presence in the reaction mixture, the reactivity was investigated both in inert gas as well as in oxygen atmosphere. X-ray photoelectron spectroscopy(XPS.and quadrupole mass spectrometry have been used for the experiment in high vacuum, while Fourier transform infrared spectroscopy and QMS have been used for the experiment in rough vacuum and under atmospheric pressure conditions). The characterisation of the sample by means of XPS, X-ray diffraction and IR spectroscopy preceded the reactivity study. When compared with Fe2O3, the Fe\u2013Ti\u2013O mixed oxide seems to be less reactive with respect to the alcohols; the interaction between alcohol and surface is mainly molecular, as in the case of TiO2. Moreover, the oxidising power of the mixed oxide is lower than that of Fe2O3 (only traces of carbonic compounds are evident)