SUPPLEMENTARY INFORMATION Articles DOI: 10.1038/s41560-017-0002-2 In the format provided by the authors and unedited. Hydrogen separation by nanocrystalline titanium nitride membranes with high hydride ion conductivity Chiharu Kura 1, Yuji Kunisada 2, Etsushi Tsuji 3, Chunyu Zhu 2, Hiroki Habazaki 2, Shinji Nagata 4, Michael P. Müller 5, Roger A. De Souza 5 and Yoshitaka Aoki 2,6 * 1 Graduate School of Chemical Sciences and Engineering, Hokkaido University, N13W8 Kita-ku, Sapporo 060-8628, Japan. 2 Faculty of Engineering, Hokkaido University, N13W8 Kita-ku, Sapporo 060-8628, Japan. 3 Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Tottori 680-8552, Japan. 4 Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan. 5 Institute of Physical Chemistry, RWTH Aachen University and JARA-FIT, 52056 Aachen, Germany. 6 JST-PRESTO, 4-1-8 Honcho, Kawaguchi 332-0012, Japan. *e-mail: y-aoki@eng.hokudai.ac.jp Nature Energy www.nature.com/natureenergy 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
Hydrogen separation by nanocrystalline titanium nitride membranes with high hydride ion conductivity Chiharu Kura, 1 Yuji Kunisada, 2 Etsushi Tsuji, 3 Chunyu Zhu, 2 Hiroki Habazaki, 2 Shinji Nagata, 4 Michael Patrick Müller, 5 Roger A. De Souza, 5 and Yoshitaka Aoki 2,6 * 1. Graduate School of Chemical Sciences and Engineering, Hokkaido University, N13W8 Kita-ku, Sapporo, 060-8628 Japan. 2. Faculty of Engineering, Hokkaido University, N13W8 Kita-ku, Sapporo, 060-8628 Japan. 3. Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Tottori 680-8552, Japan. 4. Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan. 5. Institute of Physical Chemistry, RWTH Aachen University and JARA-FIT, 52056 Aachen, Germany. 6. JST-PRESTO, 4-1-8 Honcho, Kawaguchi 332-0012, Japan.
(111) (200) (220) (311) (222) (111) (200) (220) (311) (222) Supplementary Figures a b c TiN Ti N 2 concentration 100% 2.5% TiN 0.7-500 50% 2% TiN 0.7-200 10% 1% TiN 1.0-500 5% 0.5% 3% TiN 1.0-200 Supplementary Figure 1. XRD patterns of TiN x films. a, b, TiN x films deposited on a Si wafer (100) by RF sputtering in reactive gases with various N 2 concentrations. Chamber pressure and substrate temperature were fixed at 0.9 Pa and 500 C, respectively. c, 600 nm-thick TiN x (x = 0.7 and 1.0) films deposited on a Si wafer modified by -Al 2 O 3 mesoporous layer (100 nm thickness). Sputtering was performed at 200 and 500 o C.
Supplementary Figure 2. Nitrogen stoichiometry of sputter-deposited TiN x thin films as a function of N 2 concentrations in reactive sputtering gases. x is determined by WDX.
a 10 nm (TiN 0.81 O 0.10, outer) 590 nm (TiN 0.74 O 0.035, inner) Ti C N O b 15 nm (TiN 0.96 O 0.13, outer) 585 nm (TiN 0.95 O 0.042, inner) Ti C N O Supplementary Figure 3. RBS depth profiles of TiN 0.7 and TiN 0.9 films prepared on glassy carbon substrates. The film thickness is 600 nm. Black lines are the observed and red dots the simulated. The film deposited in (a) 2.5%- and (b) 10%-N 2 gases have homogeneous matrices, and the corresponding chemical composition is (a) TiN 0.74 O 0.035 (TiN 0.7 ) and (b) TiN 0.95 O 0.042 (TiN 0.9 ), respectively. The N/Ti ratios are in agreement with the WDX analysis (see Supplementary Table 1 & Supplementary Figure 2). The surfaces of both films are oxidized by air, forming 10 nm-thick outerlayer with composition of TiN 0.81 O 0.10 for 2.5%-N 2 and TiN 0.96 O 0.13 for 10%-N 2, respectively.
a b 20 nm 20 nm Supplementary Figure 4. Cross-section TEM images showing nanogranular morphology. (a)tin 0.9 and (b) TiN 1.0.
Supplementary Figure 5. SIMS depth profiles of TiN 1.0 films (400 nm) on a Si wafer. (a) Heated in 50 vol% H 2 /Ar at 500 C for 1 h, and (b) heated in 50 vol% D 2 /Ar at 500 C for 1 h, showing the signal intensity of H (black line), D (red line), and O (blue line) impurities and the signal intensity of constituent TiN (green dashed line) and Si (yellow dashed line).
a TiN 0.7 500 o C 400 o C 300 o C 100 o C 25 o C b TiN 0.9 c TiN 1.0 Supplementary Figure 6. J H2 vs p H2 plots of TiN x membranes. a, b, c, J H2 of 2.5 m-thick TiN x membranes (x = 0.7 (a), 0.9 (b) and 1.0 (c)), plotted by the way of Sieverts solubility model.
N 1s TiN NH H 2 treat (300 o C) H 2 treat (25 o C) Supplementary Figure 7. N 1s XPS spectra of 600 nm-thick TiN 0.7 films treated in 50%-H 2 /Ar atmosphere at 25 o C and 300 o C.
a b Al 2 O 3 substrate TiN x Carbon sheet H 2 N 2 Gas chromatography Ar career gas H 2 N 2 Supplementary Figure 8. Apparatus for hydrogen permeation measurements. a, The sample holder to seal the TiN x membrane devices. b, Schematic illustration of a home-made chamber system equipped with GC.
a b p H2 Al 2 O 3 substrate J 1 J 2 P H2 TiN x p H2 Supplementary Figure 9. a, Schematic representation of hydrogen chemical potential gradients across TiN x /porous-al 2 O 3 -support membrane devices. b, φ 2 vs (p H2 +p H2 )/2 calibration curve of porous alumina support.
a (a5) Ti N H (a6) (a1) (a2) (a3) (a4) Ti-N H Ti-Ti H H Ti tet H H N TiN + 1/2H 2 b c Ti 3d N 2s N 2p Ti 32 N 24 Ti 3d H 1s N 2s N 2p Ti 32 N 24 H Supplementary Figure 10. Energy diagrams for rock salt type titanium nitride phases with various nitrogen and hydrogen point defects. a, The DFT energies calculated for 2 2 2 supercells of various hydrogen defect models. (a3) shows the total energies of the system comprising stoichiometric TiN phase (Ti 32 N 32 ) and 1/2 H 2 gas. (a1) Ti 31 N 32 (H Ti ): H defect occupying a Ti vacancy of Ti-deficient Ti 31/32 N phase. (a2) Ti 32 N 24 (H N ) : H defect occupying a N vacancy of N-deficient TiN 24/32 phase. (a4, a5, a6) Ti 32 N 32 H 1 : TiN phase with an H interstitial at (a4) tetrahedral site of fcc Ti sublattice ( tet H), (a5) center of the closest Ti-N bond ( Ti-N H) and (a6) center of the closest Ti-Ti bond ( Ti- Ti H). b, c, Partial DOS of Ti 32 N 24 and Ti 32 N 24 H. H 1s state is offset by 2.
Supplementary Tables Supplementary Table 1. Phase purity and chemical composition of TiNx films on a Si wafer. N2 concentration / % Phase Composition by WDX Composition by RBS 0.5 TiN, Ti TiN 0.15O 0.017 1 TiN, Ti TiN 0.45O 0.017 2 TiN, Ti TiN 0.63O 0.023 2.5 TiN TiN 0.71O 0.015 (TiN 0.7) TiN 0.81O 0.10 (10 nm, outer)/ TiN 0.74O 0.035 (590 nm, inner) 3 TiN TiN 0.92O 0.012 5 TiN TiN 0.94O 0.014 10 TiN TiN 0.95O 0.020 (TiN 0.9) TiN 0.96O 0.13 (15 nm, outer)/ TiN 0.95O 0.042 (585 nm, inner) 50 TiN TiN 0.98O 0.014 100 TiN TiN 1.02O 0.019 (TiN 1.0)
Supplementary Table 2. Hydrogen fluxes, hydrogen permeability, effective diffusion coefficient and the related activation energies of TiNx (x = 0.7, 0.9, 1.0) membranes. JH2 are the values for 600 nm-thick membranes. Samples JH2 at 500 o C JH2 at rt / Hydrogen Ea of permeability / Deff at 25 o C / Ea of / mol cm -2 s - mol cm -2 s - permeability at kj mol -1 cm 2 s -1 diffusivity / 1 1 500 o C / mol cm - kj mol -1 1 s -1 Pa -0.5 TiN0.7 9.0 10-7 5.3 10-7 1.3 10-12 3.1 (T 200 o C) 5.8 (T 250 o C) TiN0.9 7.6 10-7 3.3 10-7 1.1 10-12 4.5 (T 200 o C) 6.3 (T 250 o C) TiN1.0 6.5 10-7 1.1 10-7 9.1 10-13 6 (T 100 o C) 12 (T 150 o C) 2.2 10-9 3.1(T 250 o C)
Supplementary Table 3. Summary of recent reports for various hydrogen separation membranes. Materials L / µm T / o C E a / kj mol -1 J H2 / mol cm -2 s -1 Reference TiN 0.7 (this work) 0.6 500 rt TiN 0.9 (this work) 0.6 500 rt TiN 1.0 (this work) 0.6 500 rt 5.8 9.0 10-7 5.3 10-7 6.3 7.6 10-7 3.3 10-7 12 6.5 10-7 1.1 10-7 Pd 6 480 26 2.6 10-5 1 Pd 75Ag 25 25 450-3.0 10-5 2 Nb 56Ti 23Ni 21 800 400-1.4 10-6 3 V 2000 425-26 1.4 10-7 4 Ta 500 420-20 2.4 10-7 5 Nb 500 420-18 6.0 10-7 5 Ti 500 100 59 2.4 10-12 6 SrCe 0.95Eu 0.05O 3-δ 1720 650 66 7.5 10-10 7 BaCe 0.95Nd 0.05O 3-δ 700 925-1.9 10-8 8 BaCe 0.65Zr 0.20Y 0.15O 3-δ 650 755 91 2.0 10-7 9 -Ce 0.85Gd 0.15O 2-δ Ni-Ba(Ce 0.9Y 0.1)O 3-δ 230 800-5.7 10-7 10 Ni-BaCe 0.85Tb 0.05Zr 0.1O 3-δ 500 800-1.3 10-7 11
Supplementary Table 4. The concentrations of H2, N2 and Ar gases in the out gases of TiNx (x = 0.7-1.0) membranes at 25 o C, measured by GC during the permeation tests with supplying an 50%-H2/N2 gas at an entrance side. Samples Concentrations / % H 2 N 2 Ar TiN 0.7 1.80 0.0906 98.1 TiN 0.9 1.14 0.0945 98.8 TiN 1.0 0.373 0.0945 99.5
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