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Hydrogen separation by nanocrystalline titanium nitride membranes with high hydride ion conductivity


The production of pure hydrogen for use in energy applications and related industries often relies on the permeation of hydrogen through palladium-based membranes. However, the scarcity of Pd reserves necessitates the development of affordable alternatives with high hydrogen permeability. Here we report room-temperature hydrogen permeability of titanium nitrides (widely used as tough and inert coating materials) enabled by mixed hydride ion–electron conductivity. Combined spectroscopic, permeability and microgravimetric measurements reveal that nanocrystalline TiN x membranes feature enhanced grain-boundary diffusion of hydride anions associated with interfacial Ti cations on nanograins. Since the corresponding activation energies are very low (<10 kJ mol–1), these membranes yield a considerably higher room-temperature hydrogen flux than Pd membranes of equivalent thickness. Overall, the current study establishes general guidelines for developing hydride ion transport membranes based on a simple transition metal nitride for hydrogen purification, membrane reactors and other applications.

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Fig. 1: Electron microscopy images showing nanocrystalline, dense TiN x membranes formed over the porous alumina support.
Fig. 2: Hydrogen permeability of TiN x membranes at temperatures between ambient and 500 °C.
Fig. 3: Enhanced hydrogen permeability of nanocrystalline TiN x membranes with reducing grain sizes.
Fig. 4: Hydrogen solubility in TiN x films.
Fig. 5: Identification of mobile hydrogen species in TiN0.7 membranes.
Fig. 6: DFT calculations for hydrogen adsorption on the TiN surface.


  1. 1.

    Adams, B. D. & Chen, A. The role of palladium in a hydrogen economy. Mater. Today 14, 282–289 (2011).

    Article  Google Scholar 

  2. 2.

    Cornaglia, L., Munera, J. & Lombardo, E. Recent advances in catalysts, palladium alloys and high temperature WGS membrane reactors: A review. Int. J. Hydrogen Energy 40, 3423–3437 (2015).

    Article  Google Scholar 

  3. 3.

    Al-Mufachi, N. A., Rees, N. V. & Wilkens, R. S. Hydrogen selective membranes: A review of palladium-based dense metal membranes. Renew. Sust. Energ. Rev. 47, 540–551 (2015).

    Article  Google Scholar 

  4. 4.

    Rebollo, E. et al. Exceptional hydrogen permeation of all-ceramic composite robust membranes based on BaCe0.65Zr0.20Y0.15O3-δ and Y- or Gd-doped ceria. Energy Environ. Sci. 8, 3675–3686 (2015).

    Article  Google Scholar 

  5. 5.

    Escolastico, S. et al. Enhanced H2 separation through mixed proton-electron conducting membranes based on La5.5W0.8M0.2O11.25-δ. Chem. Sus. Chem 6, 1523–1532 (2013).

    Article  Google Scholar 

  6. 6.

    Yao, J. & Wang, H. Zeolitic imidazolate framework composite membranes and thin films: synthesis and applications. Chem. Soc. Rev. 43, 4470–4493 (2014).

    Article  Google Scholar 

  7. 7.

    Song, S. J., Wachsman, E. D., Rhodes, J., Dorris, S. E. & Balachandran, U. Hydrogen permeability of SrCe1−x M x O3−δ (x=0.05, M=Eu, Sm). Solid State Ionics 167, 99–105 (2004).

    Article  Google Scholar 

  8. 8.

    Zhu, Z. et al. Evaluation of hydrogen permeation properties of Ni-Ba(Zr0.7Pr0.1Y0.2)O3-δ cermet membranes. Int. J. Hydrogen Energy 39, 11683–11689 (2014).

    Article  Google Scholar 

  9. 9.

    Bouwmeester, H. J. M. & Burggraaf, A. J. in Handbook of Solid State Electrochemistry (eds Gellings, P. J. & Bouwmeester, H. J. M.) (CRC Press, Boca Raton, 1997).

    Chapter  Google Scholar 

  10. 10.

    Kreuer, K. D. Proton-conducting oxides. Annu. Rev. Mater. Res. 33, 333–359 (2003).

    Article  Google Scholar 

  11. 11.

    Yamazaki, Y. et al. Proton trapping in yttrium-doped barium zirconate. Nat. Mater. 12, 647–651 (2013).

    Article  Google Scholar 

  12. 12.

    Kim, D., Miyoshi, S., Tsuchiya, T. & Yamaguchi, S. Percolation conductivity of BaZrO3-BaFeO3 solid solutions. Solid State Ionics 262, 875–878 (2014).

    Article  Google Scholar 

  13. 13.

    Zhou, Y. et al. Strongly correlated perovskite fuel cells. Nature 534, 231–234 (2016).

    Google Scholar 

  14. 14.

    de Vos, R. M. & Verweij, H. High-selectivity, high-flux silica membranes for gas separation. Science 279, 1710–1711 (1998).

    Article  Google Scholar 

  15. 15.

    Uhlhorn, R. J. R., Zaspalis, V. T., Keizer, K. & Burggraaf, A. J. Synthesis of ceramic membranes. J. Mater. Sci. 27, 527–552 (1992).

    Article  Google Scholar 

  16. 16.

    Ramana, C. V., White, S., Esparza, N., Rangel, V. & Campbell, A. L. Crystal structure and morphology of nanocrystalline TiN thin films. J. Electron. Mater. 41, 3139–3144 (2012).

    Article  Google Scholar 

  17. 17.

    Holleck, G. L. Diffusion and solubility of hydrogen in palladium and palladium-silver alloys. J. Phys. Chem. 74, 503–511 (1970).

    Article  Google Scholar 

  18. 18.

    Bonanos, N., Huijser, A. & Poulsen, F. W. H/D isotope effects in high temperature proton conductors. Solid State Ionics 275, 9–13 (2015).

    Article  Google Scholar 

  19. 19.

    Kim, S. et al. On the conduction pathway for protons in nanocrystalline yttria-stabilized zirconia. Phys. Chem. Chem. Phys. 11, 3035–3038 (2009).

    Article  Google Scholar 

  20. 20.

    Schlom, D. G., Chen, L.-Q., Pan, X., Schmehl, A. & Zurbuchen, M. A. A thin film approach to engineering functionality into oxide. J. Am. Ceram. Soc. 91, 2429–2454 (2008).

    Article  Google Scholar 

  21. 21.

    Aoki, Y., Hashizume, M., Onoue, S. & Kunitake, T. Determination of surface area and porosity of small, nanometer-thick films by quartz crystal microbalance measurement of gas adsorption. J. Phys. Chem. B 112, 14578–14582 (2008).

    Article  Google Scholar 

  22. 22.

    Uekawa, N. & Kaneko, K. Nonstoichiometric properties of nanoporous iron oxide films. J. Phys. Chem. B 102, 8719–8724 (1998).

    Article  Google Scholar 

  23. 23.

    Pierson, H. O. Handbook of Chemical Vapor Deposition: Principle, Technology and Applications (2nd edn) (Noyes Publications, New York, 1999).

  24. 24.

    Hara, S. et al. Hydrogen diffusion coefficient and mobility in palladium as a function of equilibrium pressure evaluated by permeation measurement. J. Memb. Sci. 421, 355–360 (2015).

    Google Scholar 

  25. 25.

    Gelhausen, O. et al. Dissociation of H-related defect complexes in Mg-doped GaN. Phys. Rev. B 69, 125210 (2004).

    Article  Google Scholar 

  26. 26.

    Kleekajai, S. et al. Vibrational properties of the H-N-H complex in dilute III-N-V alloys: Infrared spectroscopy and density functional theory. Phys. Rev. B 29, 085213 (2008).

    Article  Google Scholar 

  27. 27.

    Suihkonen, S., Pimputkar, S., Speck, J. S. & Nakamura, S. Infrared absorption of hydrogen-related defects in ammonothermal GaN. Appl. Phys. Lett. 108, 202105 (2016).

    Article  Google Scholar 

  28. 28.

    Janotti, A., Zhang, S. B. & Wei, S.-H. Hydrogen vibration modes in GaP:N: the pivotal role of nitrogen in stabilizing the H* 2 complex. Phys. Rev. Lett. 88, 125506 (2002).

    Article  Google Scholar 

  29. 29.

    Janotti, A., Zhang, S. B. & Wei, S.-H. Effects of hydrogen on the electronic properties of dilute GaAsN alloys. Phys. Rev. Lett. 88, 086403 (2002).

    Article  Google Scholar 

  30. 30.

    Van de Walle, C. G. & Neugebauer, J. Universal alignment of hydrogen levels in semiconductors, insulators and solutions. Nature 423, 626–628 (2003).

    Article  Google Scholar 

  31. 31.

    Holbech, J. D., Nielsen, B. B., Jones, R., Sitch, P. & Öberg, S. H2* defect in crystalline silicon. Phys. Rev. Lett. 71, 875–878 (1993).

    Article  Google Scholar 

  32. 32.

    Sun, W. et al. Heterogeneous reduction of carbon dioxide by hydride-terminated silicon nanocrystals. Nat. Commun. 7, 125531 (2016).

    Google Scholar 

  33. 33.

    Fujii, R., Gotoh, Y., Liao, M. Y., Tsuji, H. & Ishikawa, J. Work function measurement of transition metal nitride and carbide thin films. Vacuum 80, 832–835 (2006).

    Article  Google Scholar 

  34. 34.

    Hood, D. M., Pitzer, R. & Schaefer, H. Electronic structure of homoleptic transition metal hydrides: TiH4, VH4, CrH4, MnH4, FeH4, CoH4, and NiH4. J. Chem. Phys. 71, 705–712 (1979).

    Article  Google Scholar 

  35. 35.

    Tsuchiya, B. et al. Electronic structure of the bulk of titanium hydrides fractured in ultrahigh vacuum by XPS surface analysis. J. Surf. Anal. 14, 424–427 (2008).

    Google Scholar 

  36. 36.

    Yan, Y. et al. The formation of Ti-H species at interface is lethal to the efficiency of TiO2-based dye-synthesized devices. J. Am. Chem. Soc. 139, 2083–2089 (2017).

    Article  Google Scholar 

  37. 37.

    Roesky, H. W., Bai, Y. & Noltemeyer, M. Synthesis and structure of [{(η5-C5Me5)Ti(NH)}3N], a titanium imide nitride. Angew. Chem. Int. Ed. 28, 754–755 (1989).

    Article  Google Scholar 

  38. 38.

    Abarca, A. et al. Ammonolysis of mono(pentamethylcyclopentadienyl) titanium(IV) derivatives. Inorg. Chem. 39, 642–651 (2000).

    Article  Google Scholar 

  39. 39.

    Hayashi, K., Sushko, P. V., Hashimoto, Y., Shluger, A. L. & Hosono, H. Hydrogen ion in oxide hosts hidden by hydroxide ions. Nat. Commun. 5, 35151 (2014).

    Article  Google Scholar 

  40. 40.

    Froben, F. W. & Rogge, F. Matrix infrared measurement of TiN. Chem. Phys. Lett. 78, 264–265 (1981).

    Article  Google Scholar 

  41. 41.

    Nyquis, R. A. & Kagel, R. O. Handbook of Infrared and Raman Spectra of Inorganic Compounds and Organic Salts. (Academic Press, London, 1971).

    Google Scholar 

  42. 42.

    Dementjef, A. P. et al. X-ray photoelectron spectroscopy refernce data for identification of C3N4 phase in carbon-nitogen films. Diamond Related Mater. 9, 1904–1907 (2000).

    Article  Google Scholar 

  43. 43.

    Chertihin, G. V. & Andrews, L. Reactions of laser ablated Ti atoms with hydrogen during condensation in excess argon. Infrared spectra of the TiH, TiH2, TiH3 and TiH4 molecules. J. Am. Chem. Soc. 116, 8322–8327 (1994).

    Article  Google Scholar 

  44. 44.

    Xiao, Z. L., Hauge, R. H. & Margrave, J. L. Reaction of vanadium and titanium with molecular hydrogen in Kr and Ar matrices at 12 K. J. Phys. Chem. 95, 2696–2700 (1991).

    Article  Google Scholar 

  45. 45.

    Siodmiak, M. et al. Theoretical study of hydrogen adsorption and diffusion on TiN (100) surface. Phys. Stat. Sol. B 226, 29–36 (2001).

    Article  Google Scholar 

  46. 46.

    Mario, M. & Milman, V. Density-functional study of bulk and surface properties of titanium nitride using different exchange-correlation functionals. Phys. Rev. B 62, 2899 (2000).

    Article  Google Scholar 

  47. 47.

    Conway, B. E. Two dimensional and quasi-two-dimensional isotherms for Li intercalation and upd processes at surfaces. Electrochim. Acta 38, 1249–1258 (1993).

    Article  Google Scholar 

  48. 48.

    Kobayashi, G. et al. Pure H conduction in oxyhydrides. Science. 351, 1314–1317 (2016).

    Article  Google Scholar 

  49. 49.

    Verbraeken, M. C., Cheung, C., Suard, E. & Irvine, J. T. S. High H ionic conductivity in barium hydride. Nat. Mater. 14, 95–100 (2014).

    Article  Google Scholar 

  50. 50.

    Maier, J. Nanoionics: ion transport and electrochemical storage in confined systems. Nat. Mater. 4, 805–815 (2005).

    Article  Google Scholar 

  51. 51.

    Ramanathan, S. Interface-mediated ultrafast carrier conduction in oxide thin films and superlattices for energy. J. Vac. Sci. Technol. A 27, 1126–1134 (2009).

    Article  Google Scholar 

  52. 52.

    Krukau, A. V., Vydrov, O. A., Izmaylov, A. F. & Scuseria, G. E. Influence of the exchange screening parameter on the performance of screened hybrid functionals. J. Chem. Phys. 125, 224106 (2006).

    Article  Google Scholar 

  53. 53.

    Siodmiak, M. et al. Theoretical study of hydrogen adsorption and diffusion on TiN(100) surface. Phys. Stat. Sol. 226, 29–36 (2001).

    Article  Google Scholar 

  54. 54.

    Kresse, G. & Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B 47, 558 (1993).

    Article  Google Scholar 

  55. 55.

    Kresse, G. & Hafner, J. Ab initio molecular-dynamics simulation of the liquid-metal–amorphous-semiconductor transition in germanium. Phys. Rev. B 49, 14251 (1994).

    Article  Google Scholar 

  56. 56.

    Kresse, G. & Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mat. Sci 6, 15 (1996).

    Article  Google Scholar 

  57. 57.

    Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169 (1996).

    Article  Google Scholar 

  58. 58.

    Blochl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953 (1994).

    Article  Google Scholar 

  59. 59.

    Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758 (1999).

    Article  Google Scholar 

  60. 60.

    Monkhorst, H. J. & Pack, J. D. Special points for Brillouin-zone integrations. Phys. Rev. B 13, 5188 (1976).

    MathSciNet  Article  Google Scholar 

  61. 61.

    Persson, C., Zhao, Y.-J., Lany, S. & Zunger, A. n-type doping of CuInSe2 and CuGaSe2. Phys. Rev. B 72, 035211 (2005).

    Article  Google Scholar 

  62. 62.

    Iwazaki, Y., Suzuki, T. & Tsuneyuki, S. Negatively charged hydrogen at oxygen-vacancy sites in BaTiO3: Density functional calculation. J. Appl. Phys. 108, 083705 (2010).

    Article  Google Scholar 

  63. 63.

    Climent-Font, A., Wätjen, U. & Bax, H. Quantitative RBS analysis using RUMP. On the accuracy of the He stopping in Si. Nucl. Instrum. Methods B 71, 81–86 (1992).

    Article  Google Scholar 

  64. 64.

    Itoh, N., Wu, T. H. & Haraya, K. Two- and three-dimensional analysis of diffusion through a dense membrane supported on a porous material. J. Membr. Sci. 99, 175–183 (1999).

    Article  Google Scholar 

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This work was supported by the PRESTO `Creation of Innovative Core Technology for Manufacture and Use of Energy Carriers from Renewable Energy’ project, funded by Japan Science and Technology Agency, Japan and the `Nanotechnology Platform’ programme of the MEXT Japan. C.K. was supported by the MEXT Japan through the programme for Leading Graduate Schools (Hokkaido University `Ambitious Leader’s Program’).

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Y.A. designed the present work; Y.A. and C.K. prepared the manuscript; C.K. performed the membrane fabrications, electron microscopy, FT-IR, QCM and NMR measurements and hydrogen permeation tests with supervision from Y.A., and discussed the data with Y.A., E.T., C.Z. and H.H.; SIMS measurements were performed by C.K., R.S. and M.M.; C.K. and Y.K. conducted the density functional theory calculations; Y.A. and S.N. performed Rutherford back scattering measurements.

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Correspondence to Yoshitaka Aoki.

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Kura, C., Kunisada, Y., Tsuji, E. et al. Hydrogen separation by nanocrystalline titanium nitride membranes with high hydride ion conductivity. Nat Energy 2, 786–794 (2017).

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