Various inorganic membranes have demonstrated good capability to separate hydrogen from other gases at elevated temperatures. Hydrogen-permeable, dense, mixed proton-electron conducting ceramic oxides offer superior selectivity and thermal stability, but chemically robust candidates with higher ambipolar protonic and electronic conductivity are needed. In this work, we present for the first time the results of various investigations of La 1？xSr xCrO 3？？ membranes for hydrogen production. We aim in particular to elucidate the material’s complex transport properties, involving co-ionic transport of oxide ions and protons, in addition to electron holes. This opens some new possibilities for efficient heat and mass transfer management in the production of hydrogen. Conductivity measurements as a function of pH 2 at constant pO 2 exhibit changes that reveal a significant hydration and presence of protons. The flux and production of hydrogen have been measured under different chemical gradients. In particular, the effect of water vapor in the feed and permeate gas stream sides was investigated with the aim of quantifying the ratio of hydrogen production by hydrogen flux from feed to permeate and oxygen flux the opposite way (“water splitting”). Deuterium labeling was used to unambiguously prove flux of hydrogen species.
References
[1]
Middleton, P.; Hurst, P.; Walker, G. GRACE: Pre-Combustion De-Carbonisation Hydrogen Membrane Study. Thomas, D.C., Benson, S., Eds.; Elsevier: Amsterdam, The Netherlands, 2005; Volume 1, pp. 409–425.
[2]
Beavis, R. The EU FP6 CACHET project—Final results. Energy Procedia 2011, 4, 1074–1081, doi:10.1016/j.egypro.2011.01.157.
[3]
Smith, J.B.; Aasen, K.I.; Wilhelmsen, K.; K？ka, D.; Risdal, T.; Berglund, A.; Stenersen ？stby, A.; Budd, M.; Bruun, T.; Werswick, B. Recent development in the HMR pre-combustion gas power cycle. Energy Procedia 2009, 1, 343–351, doi:10.1016/j.egypro.2009.01.047.
[4]
Fontaine, M.L.; Norby, T.; Larring, Y.; Grande, T.; Bredesen, R. Oxygen and hydrogen separation membranes based on dense ceramic conductors. Membr. Sci. Technol. 2008, 13, 401–458, doi:10.1016/S0927-5193(07)13010-2.
[5]
Norby, T.; Haugsrud, R. Dense Ceramic Membranes for Hydrogen Separation. In Nonporous Inorganic Membranes; Sammells, A.F., Mundschau, M.V., Eds.; WILEY-VCH Verlag GmbH & Co. KGaA: Weinheim, Germany, 2006; pp. 1–48.
[6]
Davies, R.; Islam, M.; Gale, J. Dopant and proton incorporation in perovskite-type zirconates. Solid State Ionics 1999, 126, 323–335, doi:10.1016/S0167-2738(99)00244-1.
[7]
Norby, T.; Wider？e, M.; Gl？ckner, R.; Larring, Y. Hydrogen in oxides. Dalton Trans. 2004, 19, 3012–3018.
[8]
Norby, T. Proton Conductivity in Perovskite Oxides. In Perovskite Oxide for Solid Oxide Fuel Cells; Ishihara, T., Ed.; Springer US: New York, NY, USA, 2009; pp. 217–241.
[9]
Bj？rheim, T.S.; Kuwabara, A.; Ahmed, I.; Haugsrud, R.; St？len, S.; Norby, T. A combined conductivity and DFT study of protons in PbZrO3 and alkaline earth zirconate perovskites. Solid State Ionics 2010, 181, 130–137, doi:10.1016/j.ssi.2009.04.013.
[10]
Gl？ckner, R. Dissolution and Transport of Protons in Some Perovskite-Related Oxides. Ph.D Thesis, University of Oslo, Oslo, Norway, 27 October 2000.
[11]
Iwahara, H. Oxide-ionic and protonic conductors based on perovskite-type oxides and their possible applications. Solid State Ionics 1992, 52, 99–104, doi:10.1016/0167-2738(92)90095-7.
[12]
Soli？s, C.; Escolastico, S.; Haugsrud, R.; Serra, J.M. La5.5WO12？δ characterization of transport properties under oxidizing conditions: A conductivity relaxation study. J. Phys. Chem. C 2011, 115, 11124–11131.
[13]
Julsrud, S.; Vigeland, B.E. A Solid Multicomponent Mixed Proton and Electron Conducting Membrane. EP Patent 1448293, 30 October 2007.
[14]
Aasen, K.; Vigeland, B.; Norby, T.; Larring, Y.; Mejdell, T. Development of a hydrogen membrane reformer based CO2 emission free gas fired power plant. Greenhouse Gas Control Technol. 7 2005, 1, 83–91.
[15]
Tezuka, K.; Hinatsu, Y.; Nakamura, A.; Inami, T.; Shimojo, Y.; Morii, Y. Magnetic and neutron diffraction study on perovskites La1？xSrxCrO3. J. Solid State Chem. 1998, 141, 404–410, doi:10.1006/jssc.1998.7961.
[16]
Schneider, S.; Roth, R.; Waring, J. Solid state reactions involving oxides of trivalent cations. J. Res. Natl. Bur. Stand. 1961, 65A, 345–374, doi:10.6028/jres.065A.037.
[17]
Peck, D.; Miller, M.; Hilpert, K. Phase diagram study in the CaO–Cr2O3–La2O3 system in air and under low oxygen pressure. Solid State Ionics 1999, 123, 47–57, doi:10.1016/S0167-2738(99)00087-9.
[18]
Peck, D.; Miller, M.; Hilpert, K. Phase diagram studies in the SrO–Cr2O3–La2O3 system in air and under low oxygen pressure. Solid State Ionics 1999, 123, 59–65, doi:10.1016/S0167-2738(99)00088-0.
[19]
Zhu, W.; Deevi, S. Development of interconnect materials for solid oxide fuel cells. Mater. Sci. Eng. A 2003, 348, 227–243, doi:10.1016/S0921-5093(02)00736-0.
[20]
Mizusaki, J.; Yamauchi, S.; Fueki, K.; Ishikawa, A. Nonstoichiometry of the perovskite-type oxide La1？xSrxCrO3-[delta]. Solid State Ionics 1984, 12, 119–124, doi:10.1016/0167-2738(84)90138-3.
[21]
Flandermeyer, B.; Nasrallah, M.; Agarwal, A.K.; Anderson, H. Defect structure of mg‐doped lacro3 model and thermogravimetric measurements. J. Amer. Ceram. Soc. 1984, 67, 195–198.
[22]
Yasuda I, H.T. Electrical Conductivity and Oxygen Chemical Diffusion Coefficients of Calcium-Doped Lanthanum Chromites, Second International Symposium on Solid Oxide Fuel Cells; Grosz F, Z.P., Singahl, S.C., Yamamoto, O., Eds.; Commision of the European Community: Athens, Greece, 1991; pp. 645–652.
[23]
Yasuda, I.; Hikita, T. Electrical conductivity and defect structure of calcium‐doped lanthanum chromites. J. Electrochem. Soc. 1993, 140, 1699–1704, doi:10.1149/1.2221626.
[24]
Fergus, J.W. Materials challenges for solid-oxide fuel cells. JOM J. Min. Metal. Mater. Soc. 2007, 59, 56–62, doi:10.1007/s11837-007-0153-x.
[25]
Koc, R.; Anderson, H.U. Liquid phase sintering of LaCrO3. J. Eur. Ceram. Soc. 1992, 9, 285–292, doi:10.1016/0955-2219(92)90063-J.
[26]
Hilpert, K.; Das, D.; Miller, M.; Peck, D.; Weiss, R. Chromium vapor species over solid oxide fuel cell interconnect materials and their potential for degradation processes. J. Electrochem. Soc. 1996, 143, 3642–3647, doi:10.1149/1.1837264.
Paulik, S.; Baskaran, S.; Armstrong, T. Mechanical properties of calcium-and strontium-substituted lanthanum chromite. J. Mater. Sci. 1998, 33, 2397–2404, doi:10.1023/A:1004359925766.
[29]
Fergus, J.W. Metallic interconnects for solid oxide fuel cells. Mater. Sci. Eng. A 2005, 397, 271–283, doi:10.1016/j.msea.2005.02.047.
[30]
Yasuda, I.; Hishinuma, M. Electrochemical properties of doped lanthanum chromites as interconnectors for solid oxide fuel cells. J. Electrochem. Soc. 1996, 143, 1583–1590, doi:10.1149/1.1836683.
[31]
Karim, D.; Aldred, A. Localized level hopping transport in La(Sr)CrO3. Phys. Rev. B 1979, 20, 2255–2263, doi:10.1103/PhysRevB.20.2255.
[32]
Yokokawa, H.; Horita, T.; Sakai, N.; Hassel, B. Oxygen Permeation and Related Phenomena of Lanthanum Calcium Chromites as SOFC Interconnects. In Proceedings of the 3rd International Symposium on Solid Oxide Fuel Cells, Honolulu, HI, USA, 1993; pp. 364–373.
[33]
Van Hassel, B.A.; Kawada, T.; Sakai, N.; Yokokawa, H.; Dokiya, M. Oxygen permeation modelling of La1？yCayCrO3？？. Solid State Ionics 1993, 66, 41–47, doi:10.1016/0167-2738(93)90026-Y.
[34]
Kawada, T.; Horita, T.; Sakai, N.; Yokokawa, H.; Dokiya, M. Experimental determination of oxygen permeation flux through bulk and grain boundary of La0.7Ca0.3CrO3. Solid State Ionics 1995, 79, 201–207, doi:10.1016/0167-2738(95)00062-B.
[35]
Weber, W.J.; Griffin, C.W.; Bates, J.L. Effects of cation substitution on electrical and thermal transport properties of YCrO3 and LaCrO3. J. Amer. Ceram. Soc. 1987, 70, 265–270, doi:10.1111/j.1151-2916.1987.tb04979.x.
