Hydrogen Sensor Application of Anodic Titanium Oxide Nanostructures

Hydrogen (H2) fuel cells have been considered a promising renewable energy source. The recent growth of H2 economy has required highly sensitive, micro-sized and cost-effective H2 sensor for monitoring concentrations and alerting to leakages due to the flammability and explosiveness of H2 Titanium dioxide (TiO2) made by electrochemical anodic oxidation has shown great potential as a H2 sensing material. The aim of this thesis is to develop highly sensitive H2 sensor using anodized TiO2. The sensor enables mass production and integration with microelectronics by preparing the oxide layer on suitable substrate. Morphology, elemental composition, crystal phase, electrical properties and H2 sensing properties of TiO2 nanostructures prepared on Ti foil, Si and SiO2/Si substrates were characterized. Initially, vertically oriented TiO2 nanotubes as the sensing material were obtained by anodizing Ti foil. The morphological properties of tubes could be tailored by varying the applied voltages of the anodization. The transparent oxide layer creates an interference color phenomena with white light illumination on the oxide surface. This coloration effect can be used to predict the morphological properties of the TiO2 nanostructures. The crystal phase transition from amorphous to anatase or rutile, or the mixture of anatase and rutile was observed with varying heat treatment temperatures. However, the H2 sensing properties of TiO2 nanotubes at room temperature were insufficient. H2 sensors using TiO2 nanostructures formed on Si and SiO2/Si substrates were demonstrated. In both cases, a Ti layer deposited on the substrates by a DC magnetron sputtering method was successfully anodized. A mesoporous TiO2 layer obtained on Si by anodization in an aqueous electrolyte at 5°C showed diode behavior, which was influenced by the work function difference of Pt metal electrodes and the oxide layer. The sensor enabled the detection of H2 (20-1000 ppm) at low operating temperatures (50–140°C) in ambient air. A Pd decorated tubular TiO2 layer was prepared on metal electrodes patterned SiO2/Si wafer by anodization in an organic electrolyte at 5°C. The sensor showed significantly enhanced H2 sensing properties, and detected hydrogen in the range of a few ppm with fast response/recovery time. The metal electrodes placed under the oxide layer also enhanced the mechanical tolerance of the sensor. The concept of TiO2 nanostructures on alternative substrates could be a prospect for microelectronic applications and mass production of gas sensors. The gas sensor properties can be further improved by modifying material morphologies and decorating it with catalytic materials.Siirretty Doriast

Index to NASA Tech Briefs, 1972

Abstracts of 1972 NASA Tech Briefs are presented. Four indexes are included: subject, personal author, originating center, and Tech Brief number

Analysis of relevant technical issues and deficiencies of the existing sensors and related initiatives currently set and working in marine environment. New generation technologies for cost-effective sensors

The last decade has seen significant growth in the field of sensor networks, which are currently collecting large amounts of environmental data. This data needs to be collected, processed, stored and made available for analysis and interpretation in a manner which is meaningful and accessible to end users and stakeholders with a range of requirements, including government agencies, environmental agencies, the research community, industry users and the public. The COMMONSENSE project aims to develop and provide cost-effective, multi-functional innovative sensors to perform reliable in-situ measurements in the marine environment. The sensors will be easily usable across several platforms, and will focus on key parameters including eutrophication, heavy metal contaminants, marine litter (microplastics) and underwater noise descriptors of the MSFD. The aims of Tasks 2.1 and 2.2 which comprise the work of this deliverable are: • To obtain a comprehensive understanding and an up-to-date state of the art of existing sensors. • To provide a working basis on “new generation” technologies in order to develop cost-effective sensors suitable for large-scale production. This deliverable will consist of an analysis of state-of-the-art solutions for the different sensors and data platforms related with COMMONSENSE project. An analysis of relevant technical issues and deficiencies of existing sensors and related initiatives currently set and working in marine environment will be performed. Existing solutions will be studied to determine the main limitations to be considered during novel sensor developments in further WP’s. Objectives & Rationale The objectives of deliverable 2.1 are: • To create a solid and robust basis for finding cheaper and innovative ways of gathering data. This is preparatory for the activities in other WPs: for WP4 (Transversal Sensor development and Sensor Integration), for WP(5-8) (Novel Sensors) to develop cost-effective sensors suitable for large-scale production, reducing costs of data collection (compared to commercially available sensors), increasing data access availability for WP9 (Field testing) when the deployment of new sensors will be drawn and then realized

Diamond and sp² carbon for green energy applications

Carbon is a ubiquitous element on earth, with 6 protons, electrons, and neutrons. It is tetravalent, with a range of hybridised bonding configurations, it can form materials with superlative and varied properties. These materials range from soft and conductive sp2 bonded allotropes like graphite and carbon nanotubes, to the insulating and hardest natural material on earth, sp3 bonded diamond. The first half of this thesis presents an investigation of the properties of a promising novel carbon nanomaterial, CNS, and its application to ultracapacitor electrodes for the first time. High surface area conductive carbon nanomaterials are capable of high power and long service life energy storage in ultracapacitors, a critical green technology. The development of this technology to increase energy density to compete with chemical batteries could accelerate a transition to sustainable energy infrastructure. CNS/polymer composite electrodes were assembled using a conductive diamond collector substrate, then characterised using electrochemical techniques to measure capacitative performance. The second half of this thesis concerns the development of amperometric dissolved oxygen sensors for extreme environments. Diamonds controllable electronic properties, corrosion resistance, wide electrochemical window, and resistance to fouling make it an ideal potential material for this application. Conductive boron doped diamond electrodes were functionalised with platinum nanoparticles. Aphotolithographyprocesswasusedtoproduceanarrayofmicrodiscelectrodesusingan SU-8 photoresist mask, for the first time in this application and material system. A custom electrochemical cell was designed and built to provide a new electrochemical capability to the lab at approximately 1/10th the cost of a commercial solution; the project will be made open source. The microdisc array was tested as an oxygen sensor using the cell; calibration standards were produced by controlling the flow of oxygen and nitrogen gasses through the cell. A control measurement was provided for by a calibrated oxygen gauge incorporated into the test cell

Sustainable Devices by Design: Thermal- and Plasma-Enabled Nanofabrication of Hierarchical Carbon Nanostructures for Bioelectronics and Supercapacitors

Graphene is promising to enable diverse technological advancements. However, major technical challenges arise in its fabrication and integration as active functional materials. This body of work exemplifies a host of thermal- and plasma-enabled techniques, designed to realize sustainable and controlled methodologies for nano-assembly. Importantly, these techniques may be tailored and broadly incorporated to harness the unique functional properties of graphene, and a host of other hierarchical nanomaterials. Together, these concepts may pave the realization of next-generation nanotechnologies which hold promise for a sustainable future

Metal Oxides and Ion-Exchanging Surfaces as pH Sensors in Liquids: State-of-the-Art and Outlook

Novel applications of online pH determinations at temperatures from -35 °C to 130 °C in technical and biological media, which are all but ideal aqueous solutions, require new approaches to pH monitoring. The glass electrode, introduced nearly hundred years ago, and chemical sensors based on field effect transistors (ISFET) show specific drawbacks with respect to handling and long-time stability. Proton sensitive metal oxides seem to be a promising and alternative to the state-of-the-art measuring methods, and might overcome some problems of classical hydrogen electrodes and reference electrodes

Index to NASA Tech Briefs, 1975

This index contains abstracts and four indexes--subject, personal author, originating Center, and Tech Brief number--for 1975 Tech Briefs

Single Compartment Micro Direct Glucose Fuel Cell

Micro fuel cells have received considerable attention over the past decade due to their high efficiency, large energy density, rapid refuelling capability and their inherent non-polluting aspect. An air breathing abiotically catalyzed single compartment micro direct glucose fuel cell (SC-µDGFC) has been developed using microfabrication technologies. The single compartment of the fuel cell was shared by the anode and cathode that had an interdigitating comb electrodes configuration. The SC-µDGFC compartment was formed of polydimethylsiloxane (PDMS) which exhibits high permeability to oxygen and served as the membrane through which oxygen from ambient environment was able to permeate to the cathode. To minimize the losses associated with fuel crossover, two features were incorporated in the fuel cell: (i) silver was used as the catalyst to selectively reduce oxygen in the presence of glucose and (ii) cathodes were made 25-45µm higher than the anode to reduce access of oxygen to the anode with nickel or platinum catalyst. For 1M glucose/2M KOH solution, an initial OCV of 120-160mV was recorded, which gradually decreased with time and stabilized at 60-75mV. For a fuel cell tested without PDMS membrane, maximum OCV of 135mV and power density of 0.38µW/cm2 was obtained

In Situ Imaging of Heterogeneous Catalysts from the Micrometer to the Nanometer Scale

The function and efficiency of a catalyst is influenced by its design on several length scales. Therefore, the characterization of catalysts by complementary techniques on all length scales is required to understand the underlying processes and to improve the catalyst function. In this work, the micrometer and nanometer scale of heterogeneous catalysts are probed by spectroscopic and microscopic methods and in situ cells suitable for studying these length scales are presented

Lanthanum tungstate membranes for H-2 extraction and CO2 utilization: Fabrication strategies based on sequential tape casting and plasma-spray physical vapor deposition

[EN] In the context of energy conversion efficiency and decreasing greenhouse gas emissions from power generation and energy-intensive industries, membrane technologies for H-2 extraction and CO2 capture and utilization become pronouncedly important. Mixed protonic-electronic conducting ceramic membranes are hence attractive for the pre-combustion integrated gasification combined cycle, specifically in the water gas shift and H-2 separation process, and also for designing catalytic membrane reactors. This work presents the fabrication, microstructure and functional properties of Lanthanum tungstates (La28-xW4+xO54+delta, LaWO) asymmetric membranes supported on porous ceramic and porous metallic substrates fabricated by means of the sequential tape casting route and plasma spray-physical vapor deposition (PS-PVD). Pure LaWO and W site substituted LaWO were employed as membrane materials due to the promising combination of properties: appreciable mixed protonic-electronic conductivity at intermediate temperatures and reducing atmospheres, good sinterability and noticeable chemical stability under harsh operating conditions. As substrate materials porous LaWO (non-substituted), MgO and Crofer22APU stainless steel were used to support various LaWO membrane layers. The effect of fabrication parameters and material combinations on the assemblies' microstructure, LaWO phase formation and gas tightness of the functional layers was explored along with the related fabrication challenges for shaping LaWO layers with sufficient quality for further practical application. The two different fabrication strategies used in the present work allow for preparing all-ceramic and ceramic-metallic assemblies with LaWO membrane layers with thicknesses between 25 and 60 mu m and H-2 flux of ca. 0.4 ml/min cm(2) measured at 825 degrees C in 50 vol% H-2 in He dry feed and humid Ar sweep configuration. Such a performance is an exceptional achievement for the LaWO based H-2 separation membranes and it is well comparable with the H-2 flux reported for other newly developed dual phase cer-cer and cer-met membranes.ProtOMem Project under the BMBF grant 03SF0537 is gratefully acknowledged. Furthermore, the authors thank Ralf Laufs for his assistance in operating the PS-PVD facility. Dr. A. Schwedt from the Central Facility for Electron Microscopy (Gemeinschaftslabor fur Elektronenmikroskopie GFE), RWTH Aachen University is acknowledged for performing the EBSD analysis on the PS-PVD samples.Ivanova, ME.; Deibert, W.; Marcano, D.; Escolástico Rozalén, S.; Mauer, G.; Meulenberg, WA.; Bram, M.... (2019). Lanthanum tungstate membranes for H-2 extraction and CO2 utilization: Fabrication strategies based on sequential tape casting and plasma-spray physical vapor deposition. Separation and Purification Technology. 219:100-112. https://doi.org/10.1016/j.seppur.2019.03.015S100112219A.A. Evers, The hydrogen society, More than just a vision? ISBN 978-3-937863-31-3, Hydrogeit Verlag, 16727 Oberkraemer, Germany, 2010.Deibert, W., Ivanova, M. E., Baumann, S., Guillon, O., & Meulenberg, W. A. (2017). Ion-conducting ceramic membrane reactors for high-temperature applications. Journal of Membrane Science, 543, 79-97. doi:10.1016/j.memsci.2017.08.016Arun C. Bose, Inorganic membranes for energy and environmental applications, Edt. A. C. Bose, ISBN: 978-0-387-34524-6, Springer Science+Business Media, LLC, 2009.M. Marrony, H. Matsumoto, N. Fukatsu, M. Stoukides, Typical applications of proton ceramic cells: a way to market? in: M. Marrony (ed.), Proton-conducting ceramics. From fundamentals to applied research, by Pan Stanford Publishing Pte. Ltd., ISBN 978-981-4613-84-2, 2016.Di Giorgio, P., & Desideri, U. (2016). Potential of Reversible Solid Oxide Cells as Electricity Storage System. Energies, 9(8), 662. doi:10.3390/en9080662A.L. Dicks, D.A.J. Rand, Fuel cell systems explained, ISBN: 9781118613528, John Wiley & Sons Ltd., 2018.Zheng, Y., Wang, J., Yu, B., Zhang, W., Chen, J., Qiao, J., & Zhang, J. (2017). A review of high temperature co-electrolysis of H2O and CO2to produce sustainable fuels using solid oxide electrolysis cells (SOECs): advanced materials and technology. Chemical Society Reviews, 46(5), 1427-1463. doi:10.1039/c6cs00403bGötz, M., Lefebvre, J., Mörs, F., McDaniel Koch, A., Graf, F., Bajohr, S., … Kolb, T. (2016). Renewable Power-to-Gas: A technological and economic review. Renewable Energy, 85, 1371-1390. doi:10.1016/j.renene.2015.07.066Woodhead publishing series in energy, Nr. 76, Membrane reactors for energy applications and basic chemical production, Edt. A. Basile, L. Di Paola, F.I. Hai, V. Piemonte, by Elsevier Ltd, ISBN 978-1-78242-223-5, 2015.Morejudo, S. H., Zanón, R., Escolástico, S., Yuste-Tirados, I., Malerød-Fjeld, H., Vestre, P. K., … Kjølseth, C. (2016). Direct conversion of methane to aromatics in a catalytic co-ionic membrane reactor. Science, 353(6299), 563-566. doi:10.1126/science.aag0274Malerød-Fjeld, H., Clark, D., Yuste-Tirados, I., Zanón, R., Catalán-Martinez, D., Beeaff, D., … Kjølseth, C. (2017). Thermo-electrochemical production of compressed hydrogen from methane with near-zero energy loss. Nature Energy, 2(12), 923-931. doi:10.1038/s41560-017-0029-4J. Franz, Energetic and economic analysis of CO2 retention in coal gasification power plants by means of polymer and ceramic membranes (dissertation, German), Ruhr-University Bochum, Germany, Shaker Verlag, 2013.Franz, J., & Scherer, V. (2011). Impact of ceramic membranes for CO2 separation on IGCC power plant performance. Energy Procedia, 4, 645-652. doi:10.1016/j.egypro.2011.01.100E. Forster, dissertation, Thermal stability of ceramic membranes and catalysts for H2-separation in CO-shift reactors, Energy and Environment Band, vol. 284, ISBN 978-3-95806-084-5, RUB 2015.Escolástico, S., Stournari, V., Malzbender, J., Haas-Santo, K., Dittmeyer, R., & Serra, J. M. (2018). Chemical stability in H2S and creep characterization of the mixed protonic conductor Nd5.5WO11.25-δ. International Journal of Hydrogen Energy, 43(17), 8342-8354. doi:10.1016/j.ijhydene.2018.03.060Mortalò, C., Rebollo, E., Escolástico, S., Deambrosis, S., Haas-Santo, K., Rancan, M., … Fabrizio, M. (2018). Enhanced sulfur tolerance of BaCe0.65Zr0.20Y0.15O3-δ-Ce0.85Gd0.15O2-δ composite for hydrogen separation membranes. Journal of Membrane Science, 564, 123-132. doi:10.1016/j.memsci.2018.07.015Matsumoto, H., Shimura, T., Higuchi, T., Tanaka, H., Katahira, K., Otake, T., … Mizusaki, J. (2005). Protonic-Electronic Mixed Conduction and Hydrogen Permeation in BaCe[sub 0.9−x]Y[sub 0.1]Ru[sub x]O[sub 3−α]. Journal of The Electrochemical Society, 152(3), A488. doi:10.1149/1.1852442Cai, M., Liu, S., Efimov, K., Caro, J., Feldhoff, A., & Wang, H. (2009). Preparation and hydrogen permeation of BaCe0.95Nd0.05O3−δ membranes. Journal of Membrane Science, 343(1-2), 90-96. doi:10.1016/j.memsci.2009.07.011U. Balachandran, J. Guan, S.E. Dorris, A.C. Bose, G.J. Stiegel, in: Proceedings of the 5th ICIM, A-410, Nagoya, Japan, 1998.Qi, X. (2000). Electrical conduction and hydrogen permeation through mixed proton–electron conducting strontium cerate membranes. Solid State Ionics, 130(1-2), 149-156. doi:10.1016/s0167-2738(00)00281-2Zhan, S., Zhu, X., Ji, B., Wang, W., Zhang, X., Wang, J., … Lin, L. (2009). Preparation and hydrogen permeation of SrCe0.95Y0.05O3−δ asymmetrical membranes. Journal of Membrane Science, 340(1-2), 241-248. doi:10.1016/j.memsci.2009.05.037Song, S. (2004). Hydrogen permeability of SrCe1−xMxO3−δ (x=0.05, M=Eu, Sm). Solid State Ionics, 167(1-2), 99-105. doi:10.1016/j.ssi.2003.12.010Wei, X., Kniep, J., & Lin, Y. S. (2009). Hydrogen permeation through terbium doped strontium cerate membranes enabled by presence of reducing gas in the downstream. Journal of Membrane Science, 345(1-2), 201-206. doi:10.1016/j.memsci.2009.08.041CHENG, S., GUPTA, V., & LIN, J. (2005). Synthesis and hydrogen permeation properties of asymmetric proton-conducting ceramic membranes. Solid State Ionics, 176(35-36), 2653-2662. doi:10.1016/j.ssi.2005.07.005Kniep, J., & Lin, Y. S. (2010). Effect of Zirconium Doping on Hydrogen Permeation through Strontium Cerate Membranes. Industrial & Engineering Chemistry Research, 49(6), 2768-2774. doi:10.1021/ie9015182LIANG, J., MAO, L., LI, L., & YUAN, W. (2010). Protonic and Electronic Conductivities and Hydrogen Permeation of SrCe0.95-xZrxTm0.05O3-δ(0≤x≤0.40) Membrane. Chinese Journal of Chemical Engineering, 18(3), 506-510. doi:10.1016/s1004-9541(10)60250-9Xing, W., Inge Dahl, P., Valland Roaas, L., Fontaine, M.-L., Larring, Y., Henriksen, P. P., & Bredesen, R. (2015). Hydrogen permeability of SrCe0.7Zr0.25Ln0.05O3− membranes (Ln=Tm and Yb). Journal of Membrane Science, 473, 327-332. doi:10.1016/j.memsci.2014.09.027Oh, T., Yoon, H., Li, J., & Wachsman, E. D. (2009). Hydrogen permeation through thin supported SrZr0.2Ce0.8−xEuxO3−δ membranes. Journal of Membrane Science, 345(1-2), 1-4. doi:10.1016/j.memsci.2009.08.031Hamakawa, S. (2002). Synthesis and hydrogen permeation properties of membranes based on dense SrCe0.95Yb0.05O3−α thin films. Solid State Ionics, 148(1-2), 71-81. doi:10.1016/s0167-2738(02)00047-4Escolástico, S., Ivanova, M., Solís, C., Roitsch, S., Meulenberg, W. A., & Serra, J. M. (2012). Improvement of transport properties and hydrogen permeation of chemically-stable proton-conducting oxides based on the system BaZr1-x-yYxMyO3-δ. RSC Advances, 2(11), 4932. doi:10.1039/c2ra20214jH. Matsumoto, T. Shimura, T. Higuchi, T. Otake, Y. Sasaki, K. Yashiro, A. Kaimai, T. Kawada, J. Mizusaki, Mixed protonic-electronic conduction properties of SrZr0.9−xY0.1RuxO3−δ, Electrochemistry, 72(12), 861–864.M.E. Ivanova, S. Escolático, M. Balaguer, J. Palisaitis, Y.J. Sohn, W.A. Meulenberg, O. Guillon, J. Mayer, J.M. Serra, Hydrogen separation through tailored dual phase membranes with nominal composition BaCe0.8Eu0.2O3−δ:Ce0.8Y0.2O2−δ at intermediate temperatures, Sci. Rep. 6 (2016) 34773–34787.S. Elangovan, B.G. Nair, T.A. Small, Ceramic mixed protonic-electronic conducting membranes for hydrogen separation (2007), US 7,258,820 B2, 1997.Rosensteel, W. A., Ricote, S., & Sullivan, N. P. (2016). Hydrogen permeation through dense BaCe 0.8 Y 0.2 O 3−δ – Ce 0.8 Y 0.2 O 2−δ composite-ceramic hydrogen separation membranes. International Journal of Hydrogen Energy, 41(4), 2598-2606. doi:10.1016/j.ijhydene.2015.11.053Rebollo, E., Mortalò, C., Escolástico, S., Boldrini, S., Barison, S., Serra, J. M., & Fabrizio, M. (2015). Exceptional hydrogen permeation of all-ceramic composite robust membranes based on BaCe0.65Zr0.20Y0.15O3−δ and Y- or Gd-doped ceria. Energy & Environmental Science, 8(12), 3675-3686. doi:10.1039/c5ee01793aMontaleone, D., Mercadelli, E., Escolástico, S., Gondolini, A., Serra, J. M., & Sanson, A. (2018). All-ceramic asymmetric membranes with superior hydrogen permeation. Journal of Materials Chemistry A, 6(32), 15718-15727. doi:10.1039/c8ta04764bKim, H., Kim, B., Lee, J., Ahn, K., Kim, H.-R., Yoon, K. J., … Lee, J.-H. (2014). Microstructural adjustment of Ni–BaCe0.9Y0.1O3−δ cermet membrane for improved hydrogen permeation. Ceramics International, 40(3), 4117-4126. doi:10.1016/j.ceramint.2013.08.066(Balu) Balachandran, U., Lee, T. H., Park, C. Y., Emerson, J. E., Picciolo, J. J., & Dorris, S. E. (2014). Dense cermet membranes for hydrogen separation. Separation and Purification Technology, 121, 54-59. doi:10.1016/j.seppur.2013.10.001Shimura, T. (2001). Proton conduction in non-perovskite-type oxides at elevated temperatures. Solid State Ionics, 143(1), 117-123. doi:10.1016/s0167-2738(01)00839-6HAUGSRUD, R. (2007). Defects and transport properties in Ln6WO12 (Ln=La, Nd, Gd, Er). Solid State Ionics, 178(7-10), 555-560. doi:10.1016/j.ssi.2007.01.004Haugsrud, R., & Kjølseth, C. (2008). Effects of protons and acceptor substitution on the electrical conductivity of La6WO12. Journal of Physics and Chemistry of Solids, 69(7), 1758-1765. doi:10.1016/j.jpcs.2008.01.002Magrasó, A., Polfus, J. M., Frontera, C., Canales-Vázquez, J., Kalland, L.-E., Hervoches, C. H., … Haugsrud, R. (2012). Complete structural model for lanthanum tungstate: a chemically stable high temperature proton conductor by means of intrinsic defects. J. Mater. Chem., 22(5), 1762-1764. doi:10.1039/c2jm14981hSeeger, J., Ivanova, M. E., Meulenberg, W. A., Sebold, D., Stöver, D., Scherb, T., … Serra, J. M. (2013). Synthesis and Characterization of Nonsubstituted and Substituted Proton-Conducting La6–xWO12–y. Inorganic Chemistry, 52(18), 10375-10386. doi:10.1021/ic401104mScherb, T., Kimber, S. A. J., Stephan, C., Henry, P. F., Schumacher, G., Escolástico, S., … Banhart, J. (2016). Nanoscale order in the frustrated mixed conductor La5.6WO12−δ. Journal of Applied Crystallography, 49(3), 997-1008. doi:10.1107/s1600576716006415Van Holt, D., Forster, E., Ivanova, M. E., Meulenberg, W. A., Müller, M., Baumann, S., & Vaßen, R. (2014). Ceramic materials for H2 transport membranes applicable for gas separation under coal-gasification-related conditions. Journal of the European Ceramic Society, 34(10), 2381-2389. doi:10.1016/j.jeurceramsoc.2014.03.001Forster, E., van Holt, D., Ivanova, M. E., Baumann, S., Meulenberg, W. A., & Müller, M. (2016). Stability of ceramic materials for H2 transport membranes in gasification environment under the influence of gas contaminants. Journal of the European Ceramic Society, 36(14), 3457-3464. doi:10.1016/j.jeurceramsoc.2016.05.021Medvedev, D., Lyagaeva, J., Plaksin, S., Demin, A., & Tsiakaras, P. (2015). Sulfur and carbon tolerance of BaCeO3–BaZrO3 proton-conducting materials. Journal of Power Sources, 273, 716-723. doi:10.1016/j.jpowsour.2014.09.116Yang, L., Wang, S., Blinn, K., Liu, M., Liu, Z., Cheng, Z., & Liu, M. (2009). Enhanced Sulfur and Coking Tolerance of a Mixed Ion Conductor for SOFCs: BaZr 0.1 Ce 0.7 Y 0.2– x Yb x O 3–δ. Science, 326(5949), 126-129. doi:10.1126/science.1174811Duan, C., Kee, R. J., Zhu, H., Karakaya, C., Chen, Y., Ricote, S., … O’Hayre, R. (2018). Highly durable, coking and sulfur tolerant, fuel-flexible protonic ceramic fuel cells. Nature, 557(7704), 217-222. doi:10.1038/s41586-018-0082-6Kreuer, K. D. (2003). Proton-Conducting Oxides. Annual Review of Materials Research, 33(1), 333-359. doi:10.1146/annurev.matsci.33.022802.091825Fantin, A., Scherb, T., Seeger, J., Schumacher, G., Gerhards, U., Ivanova, M. E., … Banhart, J. (2016). Crystal structure of Re-substituted lanthanum tungstate La5.4W1−y Re y O12–δ (0 ≤ y ≤ 0.2) studied by neutron diffraction. Journal of Applied Crystallography, 49(5), 1544-1560. doi:10.1107/s1600576716011523Fantin, A., Scherb, T., Seeger, J., Schumacher, G., Gerhards, U., Ivanova, M. E., … Banhart, J. (2017). Relation between composition and vacant oxygen sites in the mixed ionic-electronic conductors La5.4W1−MO12− (M= Mo, Re; 0 ≤y≤ 0.2) and their mother compound La6−WO12− (0.4 ≤x≤ 0.8). Solid State Ionics, 306, 104-111. doi:10.1016/j.ssi.2017.04.005J.M. Serra, S. Escolástico, M.E. Ivanova, W.A. Meulenberg, H.-P. Buchkremer, D. Stöver, US2013-0216938-A1, 2013.Escolastico, S., Seeger, J., Roitsch, S., Ivanova, M., Meulenberg, W. A., & Serra, J. M. (2013). Enhanced H2Separation through Mixed Proton-Electron Conducting Membranes Based on La5.5W0.8M0.2O11.25−δ. ChemSusChem, 6(8), 1523-1532. doi:10.1002/cssc.201300091Gil, V., Gurauskis, J., Kjølseth, C., Wiik, K., & Einarsrud, M.-A. (2013). Hydrogen permeation in asymmetric La28 − xW4 + xO54 + 3x/2 membranes. International Journal of Hydrogen Energy, 38(7), 3087-3091. doi:10.1016/j.ijhydene.2012.12.105Palmqvist, L., Lindqvist, K., & Shaw, C. (2007). Porous Multilayer PZT Materials Made by Aqueous Tape Casting. Key Engineering Materials, 333, 215-218. doi:10.4028/www.scientific.net/kem.333.215Menzler, N. H., Malzbender, J., Schoderböck, P., Kauert, R., & Buchkremer, H. P. (2013). Sequential Tape Casting of Anode-Supported Solid Oxide Fuel Cells. Fuel Cells, 14(1), 96-106. doi:10.1002/fuce.201300153Schulze-Küppers, F., Baumann, S., Tietz, F., Bouwmeester, H. J. M., & Meulenberg, W. A. (2014). Towards the fabrication of La0.98−xSrxCo0.2Fe0.8O3−δ perovskite-type oxygen transport membranes. Journal of the European Ceramic Society, 34(15), 3741-3748. doi:10.1016/j.jeurceramsoc.2014.06.012Weirich, M., Gurauskis, J., Gil, V., Wiik, K., & Einarsrud, M.-A. (2012). Preparation of lanthanum tungstate membranes by tape casting technique. International Journal of Hydrogen Energy, 37(9), 8056-8061. doi:10.1016/j.ijhydene.2011.09.083Deibert, W., Schulze-Küppers, F., Forster, E., Ivanova, M. E., Müller, M., & Meulenberg, W. A. (2017). Stability and sintering of MgO as a substrate material for Lanthanum Tungstate membranes. Journal of the European Ceramic Society, 37(2), 671-677. doi:10.1016/j.jeurceramsoc.2016.09.033Escolástico, S., Vert, V. B., & Serra, J. M. (2009). Preparation and Characterization of Nanocrystalline Mixed Proton−Electronic Conducting Materials Based on the System Ln6WO12. Chemistry of Materials, 21(14), 3079-3089. doi:10.1021/cm900067kGil, V., Strøm, R. A., Groven, L. J., & Einarsrud, M.-A. (2012). La28−xW4+xO54+3x/2Powders Prepared by Spray Pyrolysis. Journal of the American Ceramic Society, 95(11), 3403-3407. doi:10.1111/j.1551-2916.2012.05377.xIvanova, M. E., Meulenberg, W. A., Palisaitis, J., Sebold, D., Solís, C., Ziegner, M., … Guillon, O. (2015). Functional properties of La0.99X0.01Nb0.99Al0.01O4−δ and La0.99X0.01Nb0.99Ti0.01O4−δ proton conductors where X is an alkaline earth cation. Journal of the European Ceramic Society, 35(4), 1239-1253. doi:10.1016/j.jeurceramsoc.2014.11.009Dittmeyer, R., Boeltken, T., Piermartini, P., Selinsek, M., Loewert, M., Dallmann, F., … Pfeifer, P. (2017). Micro and micro membrane reactors for advanced applications in chemical energy conversion. Current Opinion in Chemical Engineering, 17, 108-125. doi:10.1016/j.coche.2017.08.001Mauer, G., Vaßen, R., & Stöver, D. (2009). Thin and Dense Ceramic Coatings by Plasma Spraying at Very Low Pressure. Journal of Thermal Spray Technology, 19(1-2), 495-501. doi:10.1007/s11666-009-9416-0Bakan, E., & Vaßen, R. (2017). Ceramic Top Coats of Plasma-Sprayed Thermal Barrier Coatings: Materials, Processes, and Properties. Journal of Thermal Spray Technology, 26(6), 992-1010. doi:10.1007/s11666-017-0597-7Jarligo, M. O., Mauer, G., Bram, M., Baumann, S., & Vaßen, R. (2013). Plasma Spray Physical Vapor Deposition of La1−x Sr x Co y Fe1−y O3−δ Thin-Film Oxygen Transport Membrane on Porous Metallic Supports. Journal of Thermal Spray Technology, 23(1-2), 213-219. doi:10.1007/s11666-013-0004-yMarcano, D., Mauer, G., Sohn, Y. J., Vaßen, R., Garcia-Fayos, J., & Serra, J. M. (2016). Controlling the stress state of La1−Sr Co Fe1−O3− oxygen transport membranes on porous metallic supports deposited by plasma spray–physical vapor process. Journal of Membrane Science, 503, 1-7. doi:10.1016/j.memsci.2015.12.029Marcano, D., Mauer, G., Vaßen, R., & Weber, A. (2017). Manufacturing of high performance solid oxide fuel cells (SOFCs) with atmospheric plasma spraying (APS) and plasma spray-physical vapor deposition (PS-PVD). Surface and Coatings Technology, 318, 170-177. doi:10.1016/j.surfcoat.2016.10.088D. Marcano, G. Mauer, Y.J. Sohn, A. Schwedt, M. Bram, M.E. Ivanova, R. Vaßen, Plasma spray-physical vapor deposition of single phase lanthanum tungstate for hydrogen gas separation membranes, t.b. submitted (2018).Brunauer, S., Emmett, P. H., & Teller, E. (1938). Adsorption of Gases in Multimolecular Layers. Journal of the American Chemical Society, 60(2), 309-319. doi:10.1021/ja01269a023Ried, P., Lorenz, C., Brönstrup, A., Graule, T., Menzler, N. H., Sitte, W., & Holtappels, P. (2008). Processing of YSZ screen printing pastes and the characterization of the electrolyte layers for anode supported SOFC. Journal of the European Ceramic Society, 28(9), 1801-1808. doi:10.1016/j.jeurceramsoc.2007.11.018R. Mücke, Sintering of ZrO2-electrolytes in multilayered assemblies of SOFC, PhD Thesis, Ruhr-University, Bochum, 2007.Amsif, M., Magrasó, A., Marrero-López, D., Ruiz-Morales, J. C., Canales-Vázquez, J., & Núñez, P. (2012). Mo-Substituted Lanthanum Tungstate La28–yW4+yO54+δ: A Competitive Mixed Electron–Proton Conductor for Gas Separation Membrane Applications. Chemistry of Materials, 24(20), 3868-3877. doi:10.1021/cm301723aDANIELS, A. U., LOWRIE, R. C., GIBBY, R. L., & CUTLER, I. B. (1962). Observations on Normal Grain Growth of Magnesia and Calcia. Journal of the American Ceramic Society, 45(6), 282-285. doi:10.1111/j.1151-2916.1962.tb11145.