Exploring the Viability of Utilizing TreatedWastewater as a Sustainable Water Resource for Green Hydrogen Generation Using Solid Oxide Electrolysis Cells (SOECs)

The European Union aims to achieve carbon neutrality by 2050, prompting substantial investments in sustainable energy research, particularly in the realm of renewable sources (RESs). Italy, anticipating an energy demand of 366 TWh by 2030, is obligated by the EU to fulfill 75% to 84% of this demand through RESs1. A promising solution to meet this requirement is the production of green hydrogen through water electrolysis, specifically employing Solid Oxide Electrolysis Cells (SOECs). SOECs offer advantages over Alkaline Electrolyzers (AEs) and Proton Exchange Membranes (PEMs) since they can utilize treated wastewaters, eliminating the necessity for pure water, which is already scarce. This study centers on exploring the potential of SOECs to operate effectively in high-temperature conditions and utilize water in its gaseous form as the inlet source, commencing with treated wastewaters derived from municipal wastewater treatment plants

Assessing the use of Treated Wastewater for Green Hydrogen via SOEC

The European Union's goal of achieving carbon neutrality by 2050 has led to significant investments in sustainable energy research, particularly from renewable sources (RESs). Italy, with a projected energy demand of 366 TWh by 2030, is mandated by the EU to satisfy 75% to 84% of this demand using RESs1. Green hydrogen production through water electrolysis, particularly using Solid Oxide Electrolysis Cells (SOECs), is seen as a promising solution. SOECs have an advantage over Alkaline Electrolyzers (AEs) and Proton Exchange Membranes (PEMs) as they can use treated wastewaters, eliminating the need for pure water, which is already in short supply. This study focuses on the potential of SOECs to operate effectively in high temperature conditions and use water in its gas form as the inlet source, starting with treated wastewaters from municipal wastewater treatment plants

Experimental approach for the study of SOFC cathodes

The suitability of impedance measurements in Solid Oxide Fuel Cells (SOFCs) is an important concern, especially in case of measuring separately the behaviour of one of the electrode when an overvoltage is applied. In this case a thin electrolyte-supported cell with the RE (Reference Electrode) coplanar with the WE (Working Electrode) is experimentally convenient, but many authors highlighted that incorrect results can be obtained if an inappropriate geometric configuration is used. In this work LSM cathodes ((La0.8Sr0.2)MnO3-x) were investigated in a Yttria-stabilised Zirconia (YSZ) electrolyte-supported cell, using an electrolyte 3 mm thick. Two types of cells were prepared: the first (Cell1) according to the geometric requirements suggested in literature: little WE (diameter 3 mm) aligned to the CE (Counter Electrode) and with equal Rpol(polarisation resistance) and time constant; RE co-planar around the WE and placed at a distance greater than three-electrolyte thicknesses from the WE; the second one (Cell2) equal to Cell1 but with a bigger WE (diameter 8 mm). Impedance measurements were carried out both in two- and three- electrode configuration, at OCV (Open Circuit Voltage) and under applied overpotentials. A preliminary comparison between the results extracted from Cell2 at two- and three- electrodes confirms that a thick electrolyte allows extracting suitable three-electrode impedance results in case of OCV and small overpotentials. On the other side, when an overpotential over 0.2 V is applied, a comparison between Cell1 and Cell2 gives quite different results. The investigation here presented considers also an experimental approach useful for the comprehension of the main phenomena governing the kinetic of the process

Utilisation of methylcellulose as a shaping agent in the fabrication of Ba_{0.95}Ca_{0.05}Ce_{0.9}Y_{0.1}O_3 proton-conducting ceramic membranes via the gelcasting method

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Inductance correction in impedance study of solid oxide fuel cells

A procedure for evaluation and elimination of errors, caused by parasitic inductance and resistance in EIS studies of two solid oxide fuel cells (SOFC) materials: yttria stabilized zirconia (YSZ) electrolyte and lanthanum strontium manganite (LSM)/YSZ composite cathode is presented in this paper. It is shown that for these low impedance systems the parasitic inductance can affect not only the high frequencies but also the middle and low ones. The parasitic errors correction procedure increases significantly the reliability of the electrochemical impedance spectroscopy (EIS) results

Graphene-based materials for wastes, biomass and CO2 valorization in catalysis: A technological perspective via molten salt synthesis

The exfoliation of graphite to graphene is one of the main methods of graphene production. In this paper, we provide an overview of the main molten salt methods for the exfoliation of graphite to graphene, including thermal and electrochemical exfoliation of graphite in molten salt. The fundamental mechanism of these methods is discussed in detail, along with the characterization techniques and instruments used to analyze the produced graphene. Additionally, the principles of eutectic salt mixtures, which play a crucial role in the exfoliation process, are discussed. The utilization of graphene-based materials in catalysis, particularly in the CO 2 and biomass valorization to produce sustainable fuels and chemicals, has been reviewed. The molten salt method is a simple and efficient way to produce graphene-based materials by using a molten salt medium to exfoliate the graphite. The purpose of this study is to provide a comprehensive overview of the current state of knowledge regarding the use of molten salt for the exfoliation of graphite to graphene, including their benefits and limitations

Electrochemical performance of Ni-based anodes for solid oxide fuel cells

The catalytic activity of Ni-based anodic materials was investigated in complete solid oxide fuel cells (SOFCs) by electrochemical analysis. Button cells, consisting of supporting yttria-stabilized zirconia (YSZ) electrolyte layer, (La1-xSrx)y MnO3 (LSM) cathode and (cermet) Ni0.5Co0.5\u2013YSZ anode were employed. Powders for anodes were obtained by wet impregnation. This pro- cedure allowed easy production of composite electrodes with homogeneous distribution of phases and controlled microstructure. Two electrodes impedance spectroscopy was carried out at different temperatures and partial pres- sures of reacting gases in order to evaluate contribution of each component to overall cell losses. Current\u2013voltage characteristic curves were also collected. Feeding with CH4 was tested and compared to H2. No deterioration of cell performance due to carbon formation at anode was observed over a test period of 100 h

Experiments on metal-Glass-metal samples simulating the fuel inlet/outlet manifolds in SOFC stacks

The investigations performed on state-of-the-art SOFC stacks operated at various electrical load for several thousand hours have underlined the importance to better understand how the sealant materials evolve during the operation period. The opportunity to operate a stack and to have access to post-experiment samples is quite unique and opened the possibility to design and operate in a suitable rig samples replicating the metalglass-metal of a stack manifold. Samples prepared with the same materials and manufacturing method as for stacks have been aged at operating conditions of the fuel inlet and outlet for 500h under a polarization of 0.8V and a temperature of 700\ub0C in dual atmosphere (i.e. air, fuel). The evolution of the glass properties has been followed in by Electrochemical Impedance Spectroscopy (EIS) with measurements performed at Open Circuit Voltage (OCV) and under polarization. EIS measurements allowed to monitor the behaviour of the investigated system during the ageing process. The bulk resistance of the glass was measured and related to the evolution of the microstructural features investigated by post experiment characterization on the cross-sections. The combination of different fuel stream composition and temperature resulted in a quite stronger evolution of the glass at the outlet