• Energy Research

Dense micrometric La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) films were deposited by spin-coating on porous LSGM scaffolds characterized by an homogeneous pore structure. Porous anodes were infiltrated with aqueous nickel nitrate solutions, dried and fired at 700 °C. Homogeneous metal coating with proper interconnections was observed by SEM, chemical stability was confirmed by XRD. Fuel cell tests and electrochemical impedance spectroscopy (EIS) were performed and discussed.

Planar sensors based on tape‐cast YSZ layers with two parallel Pt (or Au) finger electrodes, one covered with Ta (10 at.%)‐doped nanosized titania powders, were prepared and studied. The sensors were tested at various concentrations of NO2, CO, and different hydrocarbons in the 450–650°C temperature range. The sensitivity to different target gases was found to be strongly dependent on the operating temperature. The replacement of Pt electrodes with Au was effective in promoting the response to propylene. Moreover, an inversion of the polarity of the electromotive force response to NO2 gas was observed in comparison with Pt‐based sensors. The sensing mechanism is discussed.

In the current scenario of innovative energy systems, reversible solid oxide cells (r-SOCs) are widely recognized as promising devices, thanks to their high conversion efficiency in both power-to-fuel and fuel-to-power modes. A crucial aspect for their scale-up is the development of multi-functional compounds that can work as either air or fuel electrodes. The most reliable alternative to conventional materials for r-SOCs are perovskite oxides. Sr -substituted lanthanum ferrites (LSF) show large mixed ionic and electronic conductivity (MIEC) and versatile catalytic activity upon B-site doping. Nevertheless, their poor stability in highly reducing environments precludes their widespread application. In this work, 5 mol% Ru-doped lanthanum ferrite La0.6Sr0.4Fe0.95Ru0.05O3-delta (LSFR05) is investigated as a multi-functional electrode for reversible and symmetric solid oxide cells (r-SSOCs). Ru-doping promotes LSF stability, retaining a higher lattice oxygen content. Upon reduction, LSFR05 exhibits exsolution of uniformly dispersed catalytically active Fe-Ru nanoparticles. All-perovskite symmetric cells showed remarkably high power density as H2-SOFC at 850 degrees C (602 mW cm-2), while in CO2-SOEC mode a current density output of 1.39 A cm-2 at 1.5 V was obtained. With a standard 70:30 CO2:CO gas composition, the cell showed a polarization resistance as low as 165 m omega cm2. The complete SOFC-SOEC reversibility was suc-cessfully assessed for over 200 h.

In this paper, we demonstrate the high potentialities of pristine single-cation and mixed cation/anion perovskite solar cells (PSC) fabricated by sequential method deposition in p-i-n planar architecture (ITO/NiOX/Perovskite/PCBM/BCP/Ag) in ambient conditions. We applied the crystal engineering approach for perovskite deposition to control the quality and crystallinity of the light-harvesting film. The formation of a full converted and uniform perovskite absorber layer from poriferous pre-film on a planar hole transporting layer (HTL) is one of the crucial factors for the fabrication of high-performance PSCs. We show that the in-air sequential deposited MAPbI3-based PSCs on planar nickel oxide (NiOX) permitted to obtain a Power Conversion Efficiency (PCE) exceeding 14% while the (FA,MA,Cs)Pb(I,Br)3-based PSC achieved 15.6%. In this paper we also compared the influence of transporting layers on the cell performance by testing material depositions quantity and thickness (for hole transporting layer), and conditions of deposition processes (for electron transporting layer). Moreover, we optimized second step of perovskite deposition by varying the dipping time of substrates into the MA(I,Br) solution. We have shown that the layer by layer deposition of the NiOx is the key point to improve the efficiency for inverted perovskite solar cell out of glove-box using sequential deposition method, increasing the relative efficiency of +26% with respect to reference cells.

Abstract Field measurements of NO x , HCs and CO concentrations on an engine test bench were performed on YSZ-based planar sensors. Sensors with two parallel Pt finger electrodes, one coated with WO 3 thick film as sensing electrode, were fabricated. The planar sensor was positioned close to a commercial λ sensor, downstream the three-way catalytic converter of a FIAT fire 1242 cc spark ignition engine coupled to a dynamometer. The performance of the gas sensors was measured at the stoichiometric air/fuel ratio ( A / F ∼ 14.3) and in lean ( A / F ∼ 15) and rich ( A / F ∼ 13) conditions under different engine regimes (rpm and torque). The response of gas sensors was compared to the response of the commercial λ probe and related to the exhaust gas concentrations measured by spectroscopic analytical equipment at the engine exhaust end. Preliminary measurements showed promising results in terms of selectivity, sensitivity, stability, reproducibility, and response time.

This paper examines the main results of an accelerated carbonation treatment applied to different types and size fractions of stainless steel slag. The objectives of this work were essentially to assess the CO2 uptake achievable by each type of slag under mild operating conditions and to investigate the effects of carbonation on the mineralogy and leaching behaviour of the residues. The following types of materials were tested: different size fractions of commingled slag, milled electric arc furnace (EAF) slag and argon oxygen decarburization (AOD) slag. Each material was thoroughly characterized in terms of elemental composition, mineralogy and leaching behaviour. Accelerated carbonation batch experiments were performed exposing humidified (with liquid to solid ratios <0.6 l/kg) slag to 100% CO2 for operating times between 0.5 and 24 h, at controlled temperature and pressure. Maximum CO2 uptakes of 130, 180 and 300 g CO2/kg slag were achieved (at 50°C and 3 bar) for the finest fraction of the mixture, the milled EAF slag and the AOD slag, respectively. The mineralogy of each type of residue showed to be affected by the treatment, exhibiting an increase in calcite concentration and a decrease in the content of specific silicate and oxide phases. The leaching behaviour of all types of carbonated slag was also modified, exhibiting a reduction by 1–2 units of the natural pH of the materials, accompanied by a decrease of Ca release and an increase of Si leaching, as a result of modified leaching-controlling phases. In conclusion, at the tested operating conditions, AOD slag was the most reactive material with CO2. Milling, however, proved effective in increasing the carbonation yield of the EAF slag compared to that measured for the different size fractions of the commingled slag mixture.

Abstract In this work, high temperature planar sensors based on tape-cast YSZ layers with Nb2O5 n-type semiconducting oxide as sensing electrode were studied. The investigated gases were CO and different saturated and unsaturated hydrocarbons. A study on the presence of the metallic electrode under the metal oxide and on the nature of that metallic (Pt or Au) electrode was performed. Thus, different types of sensors were prepared and investigated. The sensors were tested in potentiometric devices at various concentrations of gases in the 500–700 °C temperature range. The most promising sensor in terms of selectivity, sensitivity and stability was Pt/YSZ/Nb2O5, without any metallic electrode under the Nb2O5 powder. In fact, this sensor was found totally selective to propylene with very large EMF response even at temperature as high as 700 °C (−115 mV/decade).