In Situ Raman Characterization of SOFC Materials in Operational Conditions: A Doped Ceria Study

[EN] The particular operational conditions of electrochemical cells make the simultaneous characterization of both structural and transport properties challenging. The rapidity and flexibility of the acquisition of Raman spectra places this technique as a good candidate to measure operating properties and changes. Raman spectroscopy has been applied to well-known lanthanide ceria materials and the structural dependence on the dopant has been extracted. The evolution of Pr-doped ceria with temperature has been recorded by means of a commercial cell showing a clear increment in oxygen vacancies concentration. To elucidate the changes undergone by the electrolyte or membrane material in cell operation, the detailed construction of a homemade Raman cell is reported. The cell can be electrified, sealed and different gases can be fed into the cell chambers, so that the material behavior in the reaction surface and species evolved can be tracked. The results show that the Raman technique is a feasible and rather simple experimental option for operating characterization of solid-state electrochemical cell materials, although the treatment of the extracted data is not straightforward.This research was funded by the Spanish Government (IJCI-2017-34110, RTI2018-102161 and SEV-2016-0683 grants).Solís, C.; Balaguer Ramirez, M.; Serra Alfaro, JM. (2020). In Situ Raman Characterization of SOFC Materials in Operational Conditions: A Doped Ceria Study. Membranes. 10(7):1-16. https://doi.org/10.3390/membranes10070148S116107Maher, R. C., Duboviks, V., Offer, G. J., Kishimoto, M., Brandon, N. P., & Cohen, L. F. (2013). Raman Spectroscopy of Solid Oxide Fuel Cells: Technique Overview and Application to Carbon Deposition Analysis. Fuel Cells, 13(4), 455-469. doi:10.1002/fuce.201200173Cheng, Z., Wang, J.-H., Choi, Y., Yang, L., Lin, M. C., & Liu, M. (2011). From Ni-YSZ to sulfur-tolerant anode materials for SOFCs: electrochemical behavior, in situ characterization, modeling, and future perspectives. Energy & Environmental Science, 4(11), 4380. doi:10.1039/c1ee01758fLiu, M., Lynch, M. E., Blinn, K., Alamgir, F. M., & Choi, Y. (2011). Rational SOFC material design: new advances and tools. Materials Today, 14(11), 534-546. doi:10.1016/s1369-7021(11)70279-6Maher, R. C., Shearing, P. R., Brightman, E., Brett, D. J. L., Brandon, N. P., & Cohen, L. F. (2015). Reduction Dynamics of Doped Ceria, Nickel Oxide, and Cermet Composites Probed Using In Situ Raman Spectroscopy. Advanced Science, 3(1), 1500146. doi:10.1002/advs.201500146Laguna-Bercero, M. A., & Orera, V. M. (2011). Micro-spectroscopic study of the degradation of scandia and ceria stabilized zirconia electrolytes in solid oxide electrolysis cells. International Journal of Hydrogen Energy, 36(20), 13051-13058. doi:10.1016/j.ijhydene.2011.07.082Brett, D. J. L., Kucernak, A. R., Aguiar, P., Atkins, S. C., Brandon, N. P., Clague, R., … Vesovic, V. (2010). What Happens Inside a Fuel Cell? Developing an Experimental Functional Map of Fuel Cell Performance. ChemPhysChem, 11(13), 2714-2731. doi:10.1002/cphc.201000487Sheppard, N. (1982). Recent developments in the vibrational spectroscopies (infrared, Raman, electron energy loss etc.) as applied to the structural analysis of species chemisorbed on metal surfaces. Journal of Molecular Structure, 80, 163-174. doi:10.1016/0022-2860(82)87225-6Balaguer, M., Solís, C., & Serra, J. M. (2012). Structural–Transport Properties Relationships on Ce1–xLnxO2−δ System (Ln = Gd, La, Tb, Pr, Eu, Er, Yb, Nd) and Effect of Cobalt Addition. The Journal of Physical Chemistry C, 116(14), 7975-7982. doi:10.1021/jp211594dMogensen, M. (2000). Physical, chemical and electrochemical properties of pure and doped ceria. Solid State Ionics, 129(1-4), 63-94. doi:10.1016/s0167-2738(99)00318-5Balaguer, M., García-Fayos, J., Solís, C., & Serra, J. M. (2013). Fast Oxygen Separation Through SO2- and CO2-Stable Dual-Phase Membrane Based on NiFe2O4–Ce0.8Tb0.2O2-δ. Chemistry of Materials, 25(24), 4986-4993. doi:10.1021/cm4034963Degen, T., Sadki, M., Bron, E., König, U., & Nénert, G. (2014). The HighScore suite. Powder Diffraction, 29(S2), S13-S18. doi:10.1017/s0885715614000840Rietveld, H. M. (1969). A profile refinement method for nuclear and magnetic structures. Journal of Applied Crystallography, 2(2), 65-71. doi:10.1107/s0021889869006558Rodríguez-Carvajal, J. (1993). Recent advances in magnetic structure determination by neutron powder diffraction. Physica B: Condensed Matter, 192(1-2), 55-69. doi:10.1016/0921-4526(93)90108-iShannon, R. D. (1976). Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallographica Section A, 32(5), 751-767. doi:10.1107/s0567739476001551Taniguchi, T., Watanabe, T., Sugiyama, N., Subramani, A. K., Wagata, H., Matsushita, N., & Yoshimura, M. (2009). Identifying Defects in Ceria-Based Nanocrystals by UV Resonance Raman Spectroscopy. The Journal of Physical Chemistry C, 113(46), 19789-19793. doi:10.1021/jp9049457Weber, W. H., Hass, K. C., & McBride, J. R. (1993). Raman study ofCeO2: Second-order scattering, lattice dynamics, and particle-size effects. Physical Review B, 48(1), 178-185. doi:10.1103/physrevb.48.178Parayanthal, P., & Pollak, F. H. (1984). Raman Scattering in Alloy Semiconductors: «Spatial Correlation» Model. Physical Review Letters, 52(20), 1822-1825. doi:10.1103/physrevlett.52.1822Kosacki, I., Suzuki, T., Anderson, H. U., & Colomban, P. (2002). Raman scattering and lattice defects in nanocrystalline CeO2 thin films. Solid State Ionics, 149(1-2), 99-105. doi:10.1016/s0167-2738(02)00104-2McBride, J. R., Hass, K. C., Poindexter, B. D., & Weber, W. H. (1994). Raman and x‐ray studies of Ce1−xRExO2−y, where RE=La, Pr, Nd, Eu, Gd, and Tb. Journal of Applied Physics, 76(4), 2435-2441. doi:10.1063/1.357593Esther Jeyanthi, C., Siddheswaran, R., Kumar, P., Siva Shankar, V., & Rajarajan, K. (2014). Structural and spectroscopic studies of rare earths doped ceria (RELa,Sc,Yb:CeO2) nanopowders. Ceramics International, 40(6), 8599-8605. doi:10.1016/j.ceramint.2014.01.076Shirbhate, S., Nayyar, R. N., Ojha, P. K., Yadav, A. K., & Acharya, S. (2019). Exploration of Atomic Scale Changes during Oxygen Vacancy Dissociation Mechanism in Nanostructure Co-Doped Ceria: As Electrolytes for IT-SOFC. Journal of The Electrochemical Society, 166(8), F544-F554. doi:10.1149/2.1191908jesArtini, C. (2018). Rare-Earth-Doped Ceria Systems and Their Performance as Solid Electrolytes: A Puzzling Tangle of Structural Issues at the Average and Local Scale. Inorganic Chemistry, 57(21), 13047-13062. doi:10.1021/acs.inorgchem.8b02131Spanier, J. E., Robinson, R. D., Zhang, F., Chan, S.-W., & Herman, I. P. (2001). Size-dependent properties ofCeO2−ynanoparticles as studied by Raman scattering. Physical Review B, 64(24). doi:10.1103/physrevb.64.245407Zhang, F., Chan, S.-W., Spanier, J. E., Apak, E., Jin, Q., Robinson, R. D., & Herman, I. P. (2002). Cerium oxide nanoparticles: Size-selective formation and structure analysis. Applied Physics Letters, 80(1), 127-129. doi:10.1063/1.1430502Suzuki, T., Kosacki, I., Anderson, H. U., & Colomban, P. (2004). Electrical Conductivity and Lattice Defects in Nanocrystalline Cerium Oxide Thin Films. Journal of the American Ceramic Society, 84(9), 2007-2014. doi:10.1111/j.1151-2916.2001.tb00950.xDohčević-Mitrović, Z. D., Šćepanović, M. J., Grujić-Brojčin, M. U., Popović, Z. V., Bošković, S. B., Matović, B. M., … Aldinger, F. (2006). The size and strain effects on the Raman spectra of Ce1−xNdxO2−δ (0≤x≤0.25) nanopowders. Solid State Communications, 137(7), 387-390. doi:10.1016/j.ssc.2005.12.006Balaguer, M., Solís, C., & Serra, J. M. (2011). Study of the Transport Properties of the Mixed Ionic Electronic Conductor Ce1−xTbxO2−δ + Co (x = 0.1, 0.2) and Evaluation As Oxygen-Transport Membrane. Chemistry of Materials, 23(9), 2333-2343. doi:10.1021/cm103581wBalaguer, M., Solís, C., Roitsch, S., & Serra, J. M. (2014). Engineering microstructure and redox properties in the mixed conductor Ce0.9Pr0.1O2−δ+ Co 2 mol%. Dalton Trans., 43(11), 4305-4312. doi:10.1039/c3dt52167bAcharya, S. A., Gaikwad, V. M., Sathe, V., & Kulkarni, S. K. (2014). Influence of gadolinium doping on the structure and defects of ceria under fuel cell operating temperature. Applied Physics Letters, 104(11), 113508. doi:10.1063/1.4869116Zallen, R., & Conwell, E. M. (1979). The effect of temperature on libron frequencies in molecular crystals: Implications for TTF-TCNQ. Solid State Communications, 31(8), 557-561. doi:10.1016/0038-1098(79)90252-7Hart, T. R., Aggarwal, R. L., & Lax, B. (1970). Temperature Dependence of Raman Scattering in Silicon. Physical Review B, 1(2), 638-642. doi:10.1103/physrevb.1.638Lughi, V., & Clarke, D. R. (2007). Temperature dependence of the yttria-stabilized zirconia Raman spectrum. Journal of Applied Physics, 101(5), 053524. doi:10.1063/1.2697347Long, R. Q., Huang, Y. P., & Wan, H. L. (1997). Surface Oxygen Species Over Cerium Oxide and Their Reactivities with Methane and Ethane by Means ofin situConfocal Microprobe Raman Spectroscopy. Journal of Raman Spectroscopy, 28(1), 29-32. doi:10.1002/(sici)1097-4555(199701)28:13.0.co;2-gPushkarev, V. V., Kovalchuk, V. I., & d’ Itri, J. L. (2004). Probing Defect Sites on the CeO2 Surface with Dioxygen. The Journal of Physical Chemistry B, 108(17), 5341-5348. doi:10.1021/jp0311254Weber, A., & McGinnis, E. A. (1960). The Raman spectrum of gaseous oxygen. Journal of Molecular Spectroscopy, 4(1-6), 195-200. doi:10.1016/0022-2852(60)90081-3Hornés, A., Bera, P., Fernández-García, M., Guerrero-Ruiz, A., & Martínez-Arias, A. (2012). Catalytic and redox properties of bimetallic Cu–Ni systems combined with CeO2 or Gd-doped CeO2 for methane oxidation and decomposition. Applied Catalysis B: Environmental, 111-112, 96-105. doi:10.1016/j.apcatb.2011.09.022Duboviks, V., Maher, R. C., Offer, G., Cohen, L. F., & Brandon, N. P. (2013). In-Operando Raman Spectroscopy Study of Passivation Effects on Ni-CGO Electrodes in CO2 Electrolysis Conditions. ECS Transactions, 57(1), 3111-3117. doi:10.1149/05701.3111ecstDuboviks, V., Maher, R. C., Kishimoto, M., Cohen, L. F., Brandon, N. P., & Offer, G. J. (2014). A Raman spectroscopic study of the carbon deposition mechanism on Ni/CGO electrodes during CO/CO2 electrolysis. Phys. Chem. Chem. Phys., 16(26), 13063-13068. doi:10.1039/c4cp01503

Catalytic surface promotion of highly active La0.85Sr0.15Cr0.8Ni0.2O3-delta anodes for La5.6WO11.4-delta based proton conducting fuel cells

[EN] La0.85Sr0.15CrO3-delta (LSC), La0.85Sr0.15Cr0.8Ni0.2O3-delta (LSCN) and LSCN infiltrated with Ni nanoparticles were tested as anodes for symmetrical cells based on La5.6WO11.4-delta (LWO) protonic electrolyte. These chromite-based electrode materials are compatible with LWO material, in contrast to the widely used NiO. Under typical anode reducing conditions, Ni is segregated from the LSCN lattice on the grain surface as metallic Ni nanoparticles, which are proved to be compatible with LWO in reducing conditions. These Ni nanoparticles become the catalytic active sites for the H-2 oxidation reaction in proton conducing anodes and the electrode performance is substantially improved regarding to pure LSC. Ni nanoparticle infiltration further improves the catalytic promotion of the anode, reducing the polarization resistance (R-p) previously limited by low frequency surface related processes. Indeed, the R-p, values achieved for LSCN infiltrated with Ni, e.g. 0.47 Omega cm(2) at 700 degrees C, suggest the practical application of this kind of anodes in proton conducting solid oxide fuel cells (PC-SOFC). (C) 2013 Elsevier B.V. All rights reserved.Funding from European Union (FP7 Project EFFIPRO - Grant Agreement 227560), the Spanish Government (ENE2011-24761, SEV-2012-0267 and CSIC Intramural 2008801093 grants) is kindly acknowledged. The authors thank M. Fabuel for sample preparation.Solis Díaz, C.; Balaguer Ramirez, M.; Bozza, F.; Bonanos, N.; Serra Alfaro, JM. (2014). Catalytic surface promotion of highly active La0.85Sr0.15Cr0.8Ni0.2O3-delta anodes for La5.6WO11.4-delta based proton conducting fuel cells. Applied Catalysis B Environmental. 147:203-207. https://doi.org/10.1016/j.apcatb.2013.08.04420320714

Progress in Ce(0.8)Gd(0.2)O(2-delta)protective layers for improving the CO(2)stability of Ba0.5Sr0.5Co0.8Fe0.2O3-delta O2-transport membranes

[EN] Ce0.8Gd0.2O2-delta(CGO) thin films were deposited by radio frequency (RF) magnetron sputtering and deposition temperature was changed in order to optimize the microstructure and transport properties of the obtained films. Afterwards, the films were deposited on Ba0.5Sr0.5Co0.8Fe0.2O3-delta(BSCF) oxygen separation membranes as CO(2)protective layers. Oxygen permeation was finally measured by sweeping both Ar and CO2, and the obtained results were compared with the bare BSCF membrane. It was found that the oxygen permeation of the BSCF is improved by this CGO layer, with a 4-fold improvement in the oxygen permeation flux when using pure CO(2)as the sweep gas at 900 degrees C. Therefore, these CGO protective layers are a promising way for overcoming the limitations of BSCF membranes in CO2-containing environments, associated with surface competitive O-2-CO(2)adsorption and carbonation of Ba at low temperatures.Funding from the Spanish Government (RTI2018-102161, SEV-2016-0683 and IJCI-2017-34110 grants) and Generalitat Valenciana (PROMETEO/2018/006 grant) is kindly acknowledged. The support of the Servicio de Microscopia Electronica of the Universitat Politecnica de Valencia is also acknowledged.Solis Díaz, C.; Balaguer Ramirez, M.; García-Fayos, J.; Palafox, E.; Serra Alfaro, JM. (2020). Progress in Ce(0.8)Gd(0.2)O(2-delta)protective layers for improving the CO(2)stability of Ba0.5Sr0.5Co0.8Fe0.2O3-delta O2-transport membranes. Sustainable Energy & Fuels. 4(7):3747-3752. https://doi.org/10.1039/d0se00324g374737524

Boosting methane partial oxidation on ceria through exsolution of robust Ru nanoparticles

[EN] Finding sustainable routes for the transformation of CO2 into fuels and added-value chemicals is key for mitigating greenhouse gas emission. In this respect, chemical-looping reforming coupled with CO2 splitting emerges as a promising technology to produce syngas, using waste or solar heat as an energy source. It relies on metal oxides that act as redox intermediates and, thus, the stability and catalytic activity of the oxides are crucial. For that purpose, ceria has been widely used due to its superior multicyclic stability and fast CO2 splitting kinetics. However, it also presents low capacity for oxygen exchange or supply compared with other oxides and slow methane partial oxidation kinetics, which is normally improved by cationic doping or catalytic surface activation via metal impregnation. The high temperatures (900 degrees C) required for these reactions lead to catalyst deactivation over time due to sintering of metallic clusters. In order to circumvent this issue, in this work we have utilized the exsolution method to create uniformly dispersed Ru nanoparticles (ca. 5 nm) that remain anchored to the cerium oxide backbone, guaranteeing its microstructural stability and catalytic activity over prolonged cycling. We provide evidence for metallic Ru exsolution and further demonstrate the outstanding benefits of exsolved nanoparticles in the partial oxidation of methane following a chemical-loop reforming scheme, especially in the temperature range in which industrial waste heat could be used as an energy source to drive the reaction. Remarkably, at 700 degrees C surface functionalization with exsolved Ru nanoparticles enables high CO selectivity (99% versus 62% for CeO2) and about 2 orders of magnitude faster H-2 production rates. The dispersion and size of the exsolved Ru nanoparticles were maintained after a durability test of 20 chemical loops at 900 degrees C, indicating their robustness. Overall, the results presented here point towards the unique characteristics of nanoparticle exsolution for preventing agglomeration, which could find application in other catalytic or electrochemical processes for target hydrocarbon production.AJC and MB would like to acknowledge the support of Juan de la Cierva fellowships by the Spanish Ministry of Science (grant numbers FJCI-2017-33967 and IJCI-2017-34110). We acknowledge the support of the Electronic Microscopy Service of the Universitat Politecnica de Valencia.Carrillo-Del Teso, AJ.; Navarrete Algaba, L.; Laqdiem-Marin, M.; Balaguer Ramirez, M.; Serra Alfaro, JM. (2021). Boosting methane partial oxidation on ceria through exsolution of robust Ru nanoparticles. Materials Advances. 2(9):2924-2934. https://doi.org/10.1039/d1ma00044f292429342

Hydrogen production via microwave-induced water splitting at low temperature

[EN] Hydrogen is a promising vector in the decarbonization of energy systems, but more efficient and scalable synthesis is required to enable its widespread deployment. Towards that aim, Serra et al. present a microwave-based approach that allows contactless water electrolysis that can be integrated with hydrocarbon production. Supplying global energy demand with CO2-free technologies is becoming feasible thanks to the rising affordability of renewable resources. Hydrogen is a promising vector in the decarbonization of energy systems, but more efficient and scalable synthesis is required to enable its widespread deployment. Here we report contactless H-2 production via water electrolysis mediated by the microwave-triggered redox activation of solid-state ionic materials at low temperatures (<250 degrees C). Water was reduced via reaction with non-equilibrium gadolinium-doped CeO2 that was previously in situ electrochemically deoxygenated by the sole application of microwaves. The microwave-driven reduction was identified by an instantaneous electrical conductivity rise and O-2 release. This process was cyclable, whereas H-2 yield and energy efficiency were material- and power-dependent. Deoxygenation of low-energy molecules (H2O or CO2) led to the formation of energy carriers and enabled CH4 production when integrated with a Sabatier reactor. This method could be extended to other reactions such as intensified hydrocarbons synthesis or oxidation.This work was supported by the Spanish Government (RTI2018-102161, SEV-2016-0683 and Juan de la Cierva grant IJCI-2017-34110). We thank the support of the Electronic Microscopy Service of the Universitat Politecnica de Valencia.Serra Alfaro, JM.; Borras-Morell, JF.; García-Baños, B.; Balaguer Ramirez, M.; Plaza González, PJ.; Santos-Blasco, J.; Catalán-Martínez, D.... (2020). Hydrogen production via microwave-induced water splitting at low temperature. Nature Energy. 5(11):910-919. https://doi.org/10.1038/s41560-020-00720-6910919511Serra, J. M. Electrifying chemistry with protonic cells. Nat. Energy 4, 178–179 (2019).Wei, M., McMillan, C. A. & de la Rue du Can, S. Electrification of industry: potential, challenges and outlook. Curr. Sustain. Energy Rep. 6, 140–148 (2019).Malerød-Fjeld, H. et al. Thermo-electrochemical production of compressed hydrogen from methane with near-zero energy loss. Nat. Energy 2, 923–931 (2017).Schiffer, Z. J. & Manthiram, K. Electrification and decarbonization of the chemical industry. Joule 1, 10–14 (2017).Ran, J., Zhang, J., Yu, J., Jaroniec, M. & Qiao, S. Z. Earth-abundant cocatalysts for semiconductor-based photocatalytic water splitting. Chem. Soc. Rev. 43, 7787–7812 (2014).Kudo, A. & Miseki, Y. Heterogeneous photocatalyst materials for water splitting. Chem. Soc. Rev. 38, 253–278 (2009).Vøllestad, E. et al. Mixed proton and electron conducting double perovskite anodes for stable and efficient tubular proton ceramic electrolysers. Nat. Mater. 18, 752–759 (2019).Duan, C. et al. Highly efficient reversible protonic ceramic electrochemical cells for power generation and fuel production. Nat. Energy 4, 230–240 (2019).Service, R. F. New electrolyzer splits water on the cheap. Science 367, 1181 (2020).Hamzehlouia, S., Jaffer, S. A. & Chaouki, J. Microwave heating-assisted catalytic dry reforming of methane to syngas. Sci. Rep. 8, 8940 (2018).Tsukahara, Y. et al. In situ observation of nonequilibrium local heating as an origin of special effect of microwave on chemistry. J. Phys. Chem. C 114, 8965–8970 (2010).Sholl, D. S. & Lively, R. P. Seven chemical separations to change the world. Nature 532, 435–437 (2016).Eigen, J. & Schroeder, M. Redox cycling stability of Fe2NiO4/YSZ composite storage materials for rechargeable oxide batteries. Energy Storage Mater. 28, 112–121 (2020).Catalá-Civera, J. M. et al. Dynamic measurement of dielectric properties of materials at high temperature during microwave heating in a dual mode cylindrical cavity. IEEE Trans. Microw. Theory Tech. 63, 2905–2914 (2012).García-Baños, B., Reinosa, J. J., Peñaranda-Foix, F. L., Fernández, J. F. & Catalá-Civera, J. M. Temperature assessment of microwave-enhanced heating processes. Sci. Rep. 9, 10809 (2019).Campbell, C. T. & Peden, C. H. F. Oxygen vacancies and catalysis on ceria surfaces. Science 309, 713–714 (2005).Naghavi, S. S. et al. Giant onsite electronic entropy enhances the performance of ceria for water splitting. Nat. Commun. 8, 1–6 (2017).Chueh, W. C. et al. High-flux solar-driven thermochemical dissociation of CO2 and H2O using nonstoichiometric ceria. Sci. 330, 1797–1801 (2010).Bulfin, B. et al. Analytical model of CeO2 oxidation and reduction. J. Phys. Chem. C 117, 24129–24137 (2013).Geller, A. et al. Operando tracking of electrochemical activity in solid oxide electrochemical cells by using near-infrared imaging. ChemElectroChem 2, 1527–1534 (2015).Balaguer, M., Solís, C. & Serra, J. M. Structural-transport properties relationships on Ce1–xLnxO2–δ system (Ln = Gd, La, Tb, Pr, Eu, Er, Yb, Nd) and effect of cobalt addition. J. Phys. Chem. C 116, 7975–7982 (2012).Holstein, T. Studies of polaron motion. Part II. The ‘small’ polaron. Ann. Phys. (N. Y). 8, 343–389 (1959).Seki, K. & Tachiya, M. Electric field dependence of charge mobility in energetically disordered materials: polaron aspects. Phys. Rev. B 65, 1–13 (2002).Emin, D. Generalized adiabatic polaron hopping: Meyer–Neldel compensation and Poole–Frenkel behavior. Phys. Rev. Lett. 100, 166602 (2008).Bishop, S. R., Duncan, K. L. & Wachsman, E. D. Surface and bulk oxygen non-stoichiometry and bulk chemical expansion in gadolinium-doped cerium oxide. Acta Mater. 57, 3596–3605 (2009).Suzuki, T., Kosacki, I. & Anderson, H. U. Defect and mixed conductivity in nanocrystalline doped cerium oxide. J. Am. Ceram. Soc. 85, 1492–1498 (2002).Zeng, L., Cheng, Z., Fan, J. A., Fan, L. S. & Gong, J. Metal oxide redox chemistry for chemical looping processes. Nat. Rev. Chem. 2, 349–364 (2018).Liu, W., Song, M.-S., Kong, B. & Cui, Y. Flexible and stretchable energy storage: recent advances and future perspectives. Adv. Mater. 29, 1603436 (2017).Berger, C. M. et al. Development of storage materials for high-temperature rechargeable oxide batteries. J. Energy Storage 1, 54–64 (2015).Posdziech, O., Schwarze, K. & Brabandt, J. Efficient hydrogen production for industry and electricity storage via high-temperature electrolysis. Int. J. Hydrog. Energy 44, 19089–19101 (2019).Maric, R. & Yu, H. In Nanostructures in Energy Generation, Transmission and Storage (IntechOpen, 2018).Dincer, I. & Acar, C. Review and evaluation of hydrogen production methods for better sustainability. Int. J. Hydrog. Energy 40, 11094–11111 (2015).Gielen, D. Hydrogen from Renewable Power Technology Outlook for the Energy Transition (2018).Kuckshinrichs, W., Ketelaer, T. & Koj, J. C. Economic analysis of improved alkaline water electrolysis. Front. Energy Res. 5, 1 (2017).Holladay, J. D., Hu, J., King, D. L. & Wang, Y. An overview of hydrogen production technologies. Catal. Today 139, 244–260 (2009).Glenk, G. & Reichelstein, S. Economics of converting renewable power to hydrogen. Nat. Energy 4, 216–222 (2019).Marxer, D., Furler, P., Takacs, M. & Steinfeld, A. Solar thermochemical splitting of CO2 into separate streams of CO and O2 with high selectivity, stability, conversion, and efficiency. Energy Environ. Sci. 10, 1142–1149 (2017).Vogt, C., Monai, M., Kramer, G. J. & Weckhuysen, B. M. The renaissance of the Sabatier reaction and its applications on Earth and in space. Nat. Catal. 2, 188–197 (2019).Eckle, S., Anfang, H. G. & Behm, R. J. Reaction intermediates and side products in the methanation of CO and CO2 over supported Ru catalysts in H2-rich reformate gases. J. Phys. Chem. C 115, 1361–1367 (2011).Wei, Y. et al. Three-dimensionally ordered macroporous Ce0.8Zr0.2O2-supported gold nanoparticles: synthesis with controllable size and super-catalytic performance for soot oxidation. Energy Environ. Sci. 4, 2959–2970 (2011).Santos, V. P., Pereira, M. F. R., Órfão, J. J. M. & Figueiredo, J. L. The role of lattice oxygen on the activity of manganese oxides towards the oxidation of volatile organic compounds. Appl. Catal. B 99, 353–363 (2010).Hickman, D. A. & Schmidt, L. D. Production of syngas by direct catalytic oxidation of methane. Science 259, 343–346 (1993).Feng, Z. A. et al. Fast vacancy-mediated oxygen ion incorporation across the ceria-gas electrochemical interface. Nat. Commun. 5, 1–9 (2014).Flytzani-Stephanopoulos, M., Sakbodin, M. & Wang, Z. Regenerative adsorption and removal of H2S from hot fuel gas streams by rare earth oxides. Science 312, 1508–1510 (2006).Paunović, V. et al. Europium oxybromide catalysts for efficient bromine looping in natural gas valorization. Angew. Chem. Int. Ed. 56, 9791–9795 (2017).Krupka, J. Contactless methods of conductivity and sheet resistance measurement for semiconductors, conductors and superconductors. Meas. Sci. Technol. 24, 62001 (2013).Altschuler, H. M. Handbook of Microwave Measurements Vol. 2 (Polytechnic Institute Brooklyn Press, 1963).Arai, M., Binner, J. G. P. & Cross, T. E. Comparison of techniques for measuring high-temperature microwave complex permittivity: measurements on an alumina/zircona system. J. Microw. Power Electromagn. Energy 31, 12–18 (1996).López, R. & Gómez, R. Band-gap energy estimation from diffuse reflectance measurements on sol–gel and commercial TiO2: a comparative study. J. Sol.-Gel Sci. Technol. 61, 1–7 (2012).Murphy, A. B. Band-gap determination from diffuse reflectance measurements of semiconductor films, and application to photoelectrochemical water-splitting. Sol. Energy Mater. Sol. Cells 91, 1326–1337 (2007).Skorodumova, N. V. et al. Electronic, bonding, and optical properties of CeO2 and Ce2O3 from first principles. Phys. Rev. B 64, 1151081–1151089 (2001)

Global Retinoblastoma Presentation and Analysis by National Income Level.

Importance: Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child's life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. Objectives: To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. Design, Setting, and Participants: A total of 278 retinoblastoma treatment centers were recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. Main Outcomes and Measures: Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. Results: The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4%) were female. Most patients (n = 3685 [84.7%]) were from low- and middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (n = 2638 [62.8%]), followed by strabismus (n = 429 [10.2%]) and proptosis (n = 309 [7.4%]). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis was more common in LMICs even after adjusting for age (odds ratio for low-income countries vs upper-middle-income countries and HICs, 17.92 [95% CI, 12.94-24.80], and for lower-middle-income countries vs upper-middle-income countries and HICs, 5.74 [95% CI, 4.30-7.68]). Conclusions and Relevance: This study is estimated to have included more than half of all new retinoblastoma cases worldwide in 2017. Children from LMICs, where the main global retinoblastoma burden lies, presented at an older age with more advanced disease and demonstrated a smaller proportion of familial history of retinoblastoma, likely because many do not reach a childbearing age. Given that retinoblastoma is curable, these data are concerning and mandate intervention at national and international levels. Further studies are needed to investigate factors, other than age at presentation, that may be associated with advanced disease in LMICs

The global retinoblastoma outcome study : a prospective, cluster-based analysis of 4064 patients from 149 countries

DATA SHARING : The study data will become available online once all analyses are complete.BACKGROUND : Retinoblastoma is the most common intraocular cancer worldwide. There is some evidence to suggest that major differences exist in treatment outcomes for children with retinoblastoma from different regions, but these differences have not been assessed on a global scale. We aimed to report 3-year outcomes for children with retinoblastoma globally and to investigate factors associated with survival. METHODS : We did a prospective cluster-based analysis of treatment-naive patients with retinoblastoma who were diagnosed between Jan 1, 2017, and Dec 31, 2017, then treated and followed up for 3 years. Patients were recruited from 260 specialised treatment centres worldwide. Data were obtained from participating centres on primary and additional treatments, duration of follow-up, metastasis, eye globe salvage, and survival outcome. We analysed time to death and time to enucleation with Cox regression models. FINDINGS : The cohort included 4064 children from 149 countries. The median age at diagnosis was 23·2 months (IQR 11·0–36·5). Extraocular tumour spread (cT4 of the cTNMH classification) at diagnosis was reported in five (0·8%) of 636 children from high-income countries, 55 (5·4%) of 1027 children from upper-middle-income countries, 342 (19·7%) of 1738 children from lower-middle-income countries, and 196 (42·9%) of 457 children from low-income countries. Enucleation surgery was available for all children and intravenous chemotherapy was available for 4014 (98·8%) of 4064 children. The 3-year survival rate was 99·5% (95% CI 98·8–100·0) for children from high-income countries, 91·2% (89·5–93·0) for children from upper-middle-income countries, 80·3% (78·3–82·3) for children from lower-middle-income countries, and 57·3% (52·1-63·0) for children from low-income countries. On analysis, independent factors for worse survival were residence in low-income countries compared to high-income countries (hazard ratio 16·67; 95% CI 4·76–50·00), cT4 advanced tumour compared to cT1 (8·98; 4·44–18·18), and older age at diagnosis in children up to 3 years (1·38 per year; 1·23–1·56). For children aged 3–7 years, the mortality risk decreased slightly (p=0·0104 for the change in slope). INTERPRETATION : This study, estimated to include approximately half of all new retinoblastoma cases worldwide in 2017, shows profound inequity in survival of children depending on the national income level of their country of residence. In high-income countries, death from retinoblastoma is rare, whereas in low-income countries estimated 3-year survival is just over 50%. Although essential treatments are available in nearly all countries, early diagnosis and treatment in low-income countries are key to improving survival outcomes.The Queen Elizabeth Diamond Jubilee Trust and the Wellcome Trust.https://www.thelancet.com/journals/langlo/homeam2023Paediatrics and Child Healt

Dual-phase membrane based on LaCo0.2Ni0.4Fe0.4O3-x-Ce0.8Gd0.2O2-x composition for oxygen permeation under CO2/SO2-rich gas environments

[EN] A dual-phase material with high ambipolar conductivity composed by the perovskite LaCo0.2Ni0.4Fe0.4O3-delta (LCNF) as the electronic phase and the fluorite Ce0.8Gd0.2O2-delta (CGO20) as oxide-ion conductor is proposed for use as oxygen transport membrane. The chemical compatibility between both materials depends on the synthesis method, i.e. one-pot sol-gel synthesis leads to the formation of the fluorite and the perovskite phases, as well as a third NiO-based phase. The formation of this last phase can be avoided by previously stabilizing the phases separately. The composite material shows high electrical conductivity, i.e., 7.25 S cm(-1) at 800 degrees C for LCNF-CGO20 with NiO impurity, and 2.6 S cm(-1) at 800 degrees C for LCNF-CGO20. A maximum oxygen flux, J(O-2), of 0.74 ml min(-1) cm(-2) is obtained at 1000 degrees C for a surface-activated membrane in Air/Ar gradient at ambient pressure. The membranes were tested under i) 30% CO2 in Ar, and ii) 250 ppm of SO2 in 30% CO2 in Ar, reproducing oxyfuel-like conditions. Oxygen flux decreases in these atmospheres, especially at temperatures below 900 degrees C, due to competitive adsorption of these gases with the O-2. After CO2 and SO2 exposure, initial oxygen fluxes are recovered when switching back to Ar sweeping at temperatures above 900 degrees C. Nevertheless, at temperatures < 900 degrees C the original J(O-2) before SO2 exposure is not fully recovered and postmortem FESEM images reveal the membrane surface degradation in SO2.Financial support by the Spanish Government (ENE2014-57651 and SEV-2016-0683 grants), by the EU through FP7 GREEN-CC Project (GA 608524), and by the Helmholtz Association of German Research Centers through the Helmholtz Portfolio MEM-BRAIN is gratefully acknowledged.García-Fayos, J.; Balaguer Ramirez, M.; Baunmann, S.; Serra Alfaro, JM. (2018). Dual-phase membrane based on LaCo0.2Ni0.4Fe0.4O3-x-Ce0.8Gd0.2O2-x composition for oxygen permeation under CO2/SO2-rich gas environments. Journal of Membrane Science. 548:117-124. https://doi.org/10.1016/j.memsci.2017.11.006S11712454

Co2MnO4/Ce0.8Tb0.2O2-δ Dual-Phase Membrane Material with High CO2 Stability and Enhanced Oxygen Transport for Oxycombustion Processes

[EN] Oxygen transport membranes (OTMs) are a promising oxygen production technology with high energy efficiency due to the potential for thermal integration. However, conventional perovskite materials of OTMs are unstable in CO2 atmospheres, which limits their applicability in oxycombustion processes. On the other hand, some dual-phase membranes are stable in CO2 and SO2 without permanent degradation. However, oxygen permeation is still insufficient; therefore, intensive research focuses on boosting oxygen permeation. Here, we present a novel dual-phase membrane composed of an ion-conducting fluorite phase (Ce0.8Tb0.2O2-delta, CTO) and an electronic-conducting spinel phase (Co2MnO4, CMO). CMO spinel exhibits high electronic conductivity (60 Scm(-1) at 800 degrees C) compared to other spinels used in dual-phase membranes, i.e., 230 times higher than that of NiFe2O4 (NFO). This higher conductivity ameliorates gas-solid surface exchange and bulk diffusion mechanisms. By activating the bulk membrane with a CMO/CTO porous catalytic layer, it was possible to achieve an oxygen flux of 0.25 mLmin(-1)cm(-2) for the 40CMO/60CTO (%(vol)), 680 mu m-thick membrane at 850 degrees C even under CO2-rich environments. This dual-phase membrane shows excellent potential as an oxygen transport membrane or oxygen electrode under high CO2 and oxycombustion operation.Financial support by the Spanish Ministry of Science and (PID2022-139663OB-I00 and CEX2021-001230-S grant funded by MCIN/AEI/10.13039/501100011033) by MCIN with funding from NextGenerationEU (PRTR-C17.I1) within the Planes Complementarios con CCAA (Area of Green Hydrogen and Energy) and it has been carried out in the CSIC Interdisciplinary Thematic Platform (PTI+) Transicion Energetica Sostenible+ (PTI-TRANSENER+). Also, the Universitat Politecnica de Valencia (UPV) is gratefully acknowledged. The authors would like to thank Dr. J. L. Jorda for the help with XRD. In addition, the support of the Servicio de Microscopia Electronica of the UPV is acknowledged.Laqdiem-Marin, M.; García-Fayos, J.; Carrillo-Del Teso, AJ.; Almar-Liante, L.; Balaguer Ramirez, M.; Fabuel Robledo, M.; Serra Alfaro, JM. (2023). Co2MnO4/Ce0.8Tb0.2O2-δ Dual-Phase Membrane Material with High CO2 Stability and Enhanced Oxygen Transport for Oxycombustion Processes. ACS Applied Energy Materials. 7(1):302-311. https://doi.org/10.1021/acsaem.3c026063023117

Mixed Ionic-Electronic Conduction in NiFe2O4-Ce0.8Gd0.2O2-delta Nanocomposite Thin Films for Oxygen Separation

This is the peer reviewed version of the following article: Solis Díaz, Cecilia, Toldrá-Reig, Fidel, Balaguer Ramirez, Maria, Somacescu, Simona, García-Fayos, Julio, Palafox, Elena , Serra Alfaro, José Manuel. (2018). Mixed Ionic-Electronic Conduction in NiFe2O4-Ce0.8Gd0.2O2-delta Nanocomposite Thin Films for Oxygen Separation.ChemSusChem, 11, 16, 2818-2827. DOI: 10.1002/cssc.201800420, which has been published in final form at http://doi.org/10.1002/cssc.201800420. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] NiFe2O4-Ce0.8Gd0.2O2-delta (NFO/CGO) nanocomposite thin films were prepared by simultaneously radio-frequency (RF) magnetron sputtering of both NFO and CGO targets. The aim is the growth of a CO2-stable composite layer that combines the electronic and ionic conduction of the separate NFO and the CGO phases for oxygen separation. The effect of the deposition temperature on the microstructure of the film was studied to obtain high-quality composite thin films. The ratio of both phases was changed by applying different power to each ceramic target. The amount of each deposited phase as well as the different oxidation states of the nanocomposite constituents were analyzed by means of X-ray photoelectron spectroscopy (XPS). The transport properties were studied by conductivity measurements as a function of temperature and pO(2). These analyses enabled (1)selection of the best deposition temperature (400 degrees C), (2)correlation of the p-type electronic behavior of the NFO phase with the hole hopping between Ni3+-Ni2+, and (3)following the conductivity behavior of the grown composite layer (prevailing ionic or electronic character) attained by varying the amount of each phase. The sputtered layer exhibited high ambipolar conduction and surface-exchange activity. A 150 nm-thick nanograined thin film was deposited on a 20 mu m-thick Ba0.5Sr0.5Co0.8Fe0.2O3-delta asymmetric membrane, resulting in up to 3.8 mLmin(-1)cm(-2) O-2 permeation at 1000 degrees C under CO2 atmosphere.Funding from European Union (FP7 Project Green-CC- Grant Agreement 608524), the Spanish Government (ENE2014-57651 and SEV-2016-0683) is kindly acknowledged. The authors also want to acknowledge the Electron Microscopy Service from the Universitat Politecnica de Valencia for their support in the SEM analysis performed in this work.Solis Díaz, C.; Toldrá-Reig, F.; Balaguer Ramirez, M.; Somacescu, S.; García-Fayos, J.; Palafox, E.; Serra Alfaro, JM. (2018). Mixed Ionic-Electronic Conduction in NiFe2O4-Ce0.8Gd0.2O2-delta Nanocomposite Thin Films for Oxygen Separation. ChemSusChem. 11(16):2818-2827. https://doi.org/10.1002/cssc.201800420S28182827111