Layered alkali titanates (A₂Ti_nO_2n+1): possible uses for energy/environment issues

Abstract

Uses of layered alkali titanates (A₂Ti_nO_2n+1; Na₂Ti₃O₇, K₂Ti₄O₉, and Cs₂Ti₅O₁₁) for energy and environmental issues are summarized. Layered alkali titanates of various structural types and compositions are regarded as a class of nanostructured materials based on titanium oxide frameworks. If compared with commonly known titanium dioxides (anatase and rutile), materials design based on layered alkali titanates is quite versatile due to the unique structure (nanosheet) and morphological characters (anisotropic particle shape). Recent development of various synthetic methods (solid-state reaction, flux method, and hydrothermal reaction) for controlling the particle shape and size of layered alkali titanates are discussed. The ion exchange ability of layered alkali titanate is used for the collection of metal ions from water as well as a way of their functionalization. These possible materials design made layered alkali titanates promising for energy (including catalysis, photocatalysts, and battery) and environmental (metal ion concentration from aqueous environments) applications.

Key words： layered alkali titanates; photocatalysis; hydrogen evdution; metal ions collection

Acknowledgments

This work was supported by the Research Chair Grant 2017 (Grant No. FDA-CO-2560-5655) from the National Science and Technology Development Agency (NSTDA), Thailand, the Program Management Unit for Human Resources & Institutional Development, Research and Innovation, NXPO (B05F630117), Thailand, and the MEXT Promotion of Distinctive Joint Research Center Program (Grant No. JPMXP0618217662).

References

1 Wang L, Sasaki T. Titanium oxide nanosheets: graphene analogues with versatile functionalities. Chemical Reviews, 2014, 114(19): 9455–9486

2 Ogawa M, Saito K, Sohmiya M. A controlled spatial distribution of functional units in the two dimensional nanospace of layered silicates and titanates. Dalton Transactions (Cambridge, England), 2014, 43(27): 10340–10354

3 Hong Z, Wei M. Layered titanate nanostructures and their derivatives as negative electrode materials for lithium-ion batteries. Journal of Materials Chemistry A, Materials for Energy and Sustainability, 2013, 1(14): 4403–4414

4 Chen C, Sewvandi G A, Kusunose T, Synthesis of {010}-faceted anatase TiO₂ nanoparticles from layered titanate for dye-sensitized solar cells. CrystEngComm, 2014, 16(37): 8885–8895

5 Okada T, Ide Y, Ogawa M. Organic-inorganic hybrids based on ultrathin oxide layers: designed nanostructures for molecular recognition. Chemistry, an Asian Journal, 2012, 7(9): 1980–1992

6 Kudo A, Miseki Y. Heterogeneous photocatalyst materials for water splitting. Chemical Society Reviews, 2009, 38(1): 253–278

7 Ide Y, Sadakane M, Sano T, Functionalization of layered titanates. Journal of Nanoscience and Nanotechnology, 2014, 14(3): 2135–2147

8 Kim I Y, Jo Y K, Lee J M, Unique advantages of exfoliated 2D nanosheets for tailoring the functionalities of nanocomposites. Journal of Physical Chemistry Letters, 2014, 5(23): 4149–4161

9 Sasaki T, Watanabe M, Komatsu Y, Layered hydrous titanium dioxide: potassium ion exchange and structural characterization. Inorganic Chemistry, 1985, 24(14): 2265–2271

10 Dion M, Piffard Y, Tournoux M. The tetratitanates M₂Ti₄O₉ (M= Li, Na, K, Rb, Cs, Tl, Ag). Journal of Inorganic and Nuclear Chemistry, 1978, 40(5): 917–918

11 Izawa H, Kikkawa S, Koizumi M. Formation and properties of n-alkylammonium complexes with layered tri- and tetra-titanates. Polyhedron, 1983, 2(8): 741–744

12 Miyamoto N, Kuroda K, Ogawa M. Exfoliation and film preparation of a layered titanate, Na₂Ti₃O₇, and intercalation of pseudoisocyanine dye. Journal of Materials Chemistry, 2004, 14(2): 165–170

13 Allen M R, Thibert A, Sabio E M, Evolution of physical and photocatalytic properties in the layered titanates A₂Ti₄O₉ (A= K, H) and in nanosheets derived by chemical exfoliation. Chemistry of Materials, 2010, 22(3): 1220–1228

14 Anderson M W, Klinowski J. Layered titanate pillared with alumina. Inorganic Chemistry, 1990, 29(17): 3260–3263

15 Ma R, Sasaki T. Two-dimensional oxide and hydroxide nanosheets: controllable high-quality exfoliation, molecular assembly, and exploration of functionality. Accounts of Chemical Research, 2015, 48(1): 136–143

16 Xiong Z, Zhao X S. Preparation of layered titanate with interlayer cadmium sulfide particles for visible-light-assisted dye degradation. RSC Advances, 2014, 4(106): 61960–61967

17 Sehati S, Entezari M H. Sono-intercalation of CdS nanoparticles into the layers of titanate facilitates the sunlight degradation of Congo red. Journal of Colloid and Interface Science, 2016, 462: 130–139

18 Andersson S, Wadsley A D. The crystal structure of Na₂Ti₃O₇. Acta Crystallographica, 1961, 14(12): 1245–1249

19 Andersson S, Wadsley A D, Nilsson R, The crystal structure of K₂Ti₂O₅. Acta Chemica Scandinavica, 1961, 15: 663–669

20 Grey I E, Madsen I C, Watts J A, New cesium titanate layer structures. Journal of Solid State Chemistry, 1985, 58(3): 350–356

21 Andersson S, Wadsley A D. The structures of Na₂Ti₆O₁₃ and Rb₂Ti₆O₁₃ and the alkali metal titanates. Acta Crystallographica, 1962, 15(3): 194–201

22 Berry K L, Aftandilian V D, Gilbert W W, Potassium tetra- and hexatitanates. Journal of Inorganic and Nuclear Chemistry, 1960, 14(3–4): 231–239

23 Izawa H, Kikkawa S, Koizumi M. Ion exchange and dehydration of layered [sodium and potassium] titanates, Na₂Ti₃O₇ and K₂Ti₄O₉. Journal of Physical Chemistry, 1982, 86(25): 5023–5026

24 Kwiatkowska J, Grey I E, Madsen I C, An X-ray and neutron diffraction study of cesium titanates, Cs₂Ti₅O₁₁ and Cs₂Ti₅O₁₁.X₂O, X = H, D. Acta Crystallographica. Section B, Structural Crystallography and Crystal Chemistry, 1987, 43(3): 258–265

25 Bursill L A, Smith D J, Kwiatkowska J. Identifying characteristics of the fibrous cesium titanate Cs₂Ti₅O₁₁. Journal of Solid State Chemistry, 1987, 69(2): 360–368

26 Fujiki Y. Growth of mixed fibers of potassium-tetratitanate and-dititanate by slow-cooling calcination method. Journal of the Ceramic Association, Japan, 1982, 90(1046): 624–626

27 Kajiwara M. The formation of potassium titanate fibre with flux methods. Journal of Materials Science, 1987, 22(4): 1223–1227

28 Lee J K, Lee K H, Kim H. Microstructural evolution of potassium titanate whiskers during the synthesis by the calcination and slow-cooling method. Journal of Materials Science, 1996, 31(20): 5493–5498

29 Izawa H, Kikkawa S, Koizumi M. Hydrothermal synthesis of sodium trititanate and preparation of fibrous H₂Ti₃O₇. Journal of the Japan Society of Powder and Powder Metallurgy, 1986, 33(7): 353–355

30 Masaki N, Uchida S, Yamane H, Hydrothermal synthesis of potassium titanates in Ti-KOH^-H₂O system. Journal of Materials Science, 2000, 35(13): 3307–3311

31 Kitano M, Wada E, Nakajima K, Protonated titanate nanotubes with lewis and brønsted acidity: relationship between nanotube structure and catalytic activity. Chemistry of Materials, 2013, 25(3): 385–393

32 Ma R, Fukuda K, Sasaki T, Structural features of titanate nanotubes/nanobelts revealed by Raman, X-ray absorption fine structure and electron diffraction characterizations. Journal of Physical Chemistry B, 2005, 109(13): 6210–6214

33 Lan Y, Gao X, Zhu H, Titanate nanotubes and nanorods prepared from rutile powder. Advanced Functional Materials, 2005, 15(8): 1310–1318

34 Thennarasu S, Rajasekar K, Balkis Ameen K. Hydrothermal temperature as a morphological control factor: preparation, characterization and photocatalytic activity of titanate nanotubes and nanoribbons. Journal of Molecular Structure, 2013, 1049: 446–457

35 Sakurai Y, Yoshida T. Synthesis of K₂Ti₄O₉ by the hydrolysis of KOH-Ti(iso-C₃H₇O)₄ ethanol solution. Journal of the Ceramic Society of Japan, 1991, 99(1146): 105–107

36 Yang J, Li D, Wang X, Study on the synthesis and ion-exchange properties of layered titanate Na₂Ti₃O₇ powders with different sizes. Journal of Materials Science, 2003, 38(13): 2907–2911

37 Bao N, Feng X, Shen L, Calcination syntheses of a series of potassium titanates and their morphologic evolution. Crystal Growth & Design, 2002, 2(5): 437–442

38 Bao N, Shen L, Feng X, High quality and yield in potassium titanate whiskers synthesized by calcination from hydrous titania. Journal of the American Ceramic Society, 2004, 87(3): 326–330

39 Yakubovich O V, Kireev V V. Refinement of the crystal structure of Na₂Ti₃O₇. Crystallography Reports, 2003, 48(1): 24–28

40 Fujiki Y, Ohta N. The flux growth reactions of potassium tetratitanate (K₂Ti₄O₉) fibers. Journal of the Ceramic Association, Japan, 1980, 88(1015): 111–116

41 Bavykin D V, Parmon V N, Lapkin A A, The effect of hydrothermal conditions on the mesoporous structure of TiO₂ nanotubes. Journal of Materials Chemistry, 2004, 14(22): 3370–3377

42 Gao T, Fjellvåg H, Norby P. Crystal structures of titanate nanotubes: a Raman scattering study. Inorganic Chemistry, 2009, 48(4): 1423–1432

43 Yang D, Zheng Z, Yuan Y, Sorption induced structural deformation of sodium hexa-titanate nanofibers and their ability to selectively trap radioactive Ra(ii) ions from water. Physical Chemistry Chemical Physics, 2010, 12(6): 1271–1277

44 Feng M, You W, Wu Z, Mildly alkaline preparation and methylene blue adsorption capacity of hierarchical flower-like sodium titanate. ACS Applied Materials & Interfaces, 2013, 5(23): 12654–12662

45 Magalhães Nunes L, Gouveia de Souza A, Fernandes de Farias R. Synthesis of new compounds involving layered titanates and niobates with copper(II). Journal of Alloys and Compounds, 2001, 319(1–2): 94–99

46 Yang D, Zheng Z, Liu H, Layered titanate nanofibers as efficient adsorbents for removal of toxic radioactive and heavy metal ions from water. Journal of Physical Chemistry C, 2008, 112(42): 16275–16280

47 Li G, Zhang L, Fang M. Facile fabrication of sodium titanate nanostructures using metatitanic acid (TiO₂⋅H₂O) and its adsorption property. Journal of Nanomaterials, 2012: 875295

48 Li N, Zhang L, Chen Y, Highly efficient, irreversible and selective ion exchange property of layered titanate nanostructures. Advanced Functional Materials, 2012, 22(4): 835–841

49 Wang T, Liu W, Xiong L, Influence of pH, ionic strength and humic acid on competitive adsorption of Pb(II), Cd(II) and Cr(III) onto titanate nanotubes. Chemical Engineering Journal, 2013, 215–216: 366–374

50 Liu W, Sun W, Han Y, Adsorption of Cu(II) and Cd(II) on titanate nanomaterials synthesized via hydrothermal method under different NaOH concentrations: role of sodium content. Colloids and Surfaces A, Physicochemical and Engineering Aspects, 2014, 452: 138–147

51 Vithal M, Rama Krishna S, Ravi G, Synthesis of Cu²⁺ and Ag⁺ doped Na₂Ti₃O₇ by a facile ion-exchange method as visible-light-driven photocatalysts. Ceramics International, 2013, 39(7): 8429–8439

52 Gu X, Chen F, Zhao B, Photocatalytic reactivity of Ce-intercalated layered titanate prepared with a hybrid method based on ion-exchange and thermal treatment. Superlattices and Microstructures, 2011, 50(2): 107–118

53 Ikenaga K, Kurokawa H, Ohshima M A, New development of inorganic ion exchanger: ion-exchange reaction of layered sodium titanate (Na₂Ti₃O₇) with mono, di, and trivalent ions. Journal of Ion Exchange, 2005, 16(1): 10–17

54 Liu W, Zhao X, Wang T, Selective and irreversible adsorption of mercury(ii) from aqueous solution by a flower-like titanate nanomaterial. Journal of Materials Chemistry A, Materials for Energy and Sustainability, 2015, 3(34): 17676–17684

55 Izawa H, Kikkawa S, Koizumi M. Cation exchange selectivity of layered titanates, H₂Ti₃O₇. Journal of Solid State Chemistry, 1985, 60(2): 264–267

56 Sasaki T, Komatsu Y, Fujiki Y. Protonated pentatitanate: preparation, characterizations and cation intercalation. Chemistry of Materials, 1992, 4(4): 894–899

57 Komatsu Y, Fujiki Y, Sasaki T. Ion-exchange equilibrium of alkali metal ions between crystalline hydrous titanium dioxide fibers and aqueous solutions. Bunseki Kagaku, 1982, 31(7): E225–E229

58 Komatsu Y, Fujiki Y, Sasaki T. Adsorption of alkaline earth metal ions on crystalline hydrous titanium dioxide fibers at 298 to 353K. Bunseki Kagaku, 1984, 33(5): E159–E162

59 Komatsu Y, Fujiki Y, Sasaki T. Distribution coefficients of alkaline earth metal ions and their possible applications on crystalline hydrous titanium dioxide fibers. Bunseki Kagaku, 1983, 32(2): E33–E39

60 Szirmai P, Stevens J, Horváth E, Competitive ion-exchange of manganese and gadolinium in titanate nanotubes. Catalysis Today, 2017, 284: 146–152

61 Song X, Yang E, Zheng Y. Synthesis of M_xH_yTi₃O₇ nanotubes by simple ion-exchanged process and their adsorption property. Chinese Science Bulletin, 2007, 52(18): 2491–2495

62 Torrente-Murciano L, Lapkin A A, Bavykin D V, Highly selective Pd/titanate nanotube catalysts for the double-bond migration reaction. Journal of Catalysis, 2007, 245(2): 272–278

63 Chang T H. Synthesis and characterization of europium-exchanged titanate nanoporous phosphors. Journal of the Chinese Chemical Society (Taipei), 2016, 63(2): 233–238

64 Huang J, Cao Y, Liu Z, Efficient removal of heavy metal ions from water system by titanate nanoflowers. Chemical Engineering Journal, 2012, 180: 75–80

65 Izawa H, Kikkawa S, Koizumi M. Europium³⁺ and terbium³⁺ intercalations into layered titanic acids H₂Ti₃O₇ and H₂Ti₄O₉.H₂O using ion-exchange reaction. Nippon Kagaku Kaishi, 1987, 3(3): 397–399

66 Izawa H, Kikkawa S, Koizumi M. Effect of intercalated alkylammonium on cation exchange properties of H₂Ti₃O₇. Journal of Solid State Chemistry, 1987, 69(2): 336–342

67 Komatsu Y, Fujiki Y, Sasaki T. Adsorption of cobalt(II) ions on crystalline hydrous titanium dioxide fibers at 298 to 423 K. Bulletin of the Chemical Society of Japan, 1986, 59(1): 49–52

68 Sasaki T, Komatsu Y, Fujiki Y. Distribution coefficients of lanthanide elements and some separations on layered hydrous titanium dioxide. Journal of Radioanalytical and Nuclear Chemistry, 1986, 107(2): 111–119

69 Sasaki T, Komatsu Y, Fujiki Y. Formation and characterization of layered lithium titanate hydrate. Materials Research Bulletin, 1987, 22(10): 1321–1328

70 Shannon R D, Prewitt C T. Effective ionic radii in oxides and fluorides. Acta Crystallographica. Section B, Structural Crystallography and Crystal Chemistry, 1969, 25(5): 925–946

71 Saothayanun T K, Sirinakorn T T, Ogawa M. Ion exchange of layered alkali titanates (Na₂Ti₃O₇, K₂Ti₄O₉, and Cs₂Ti₅O₁₁) with alkali halides by the solid-state reactions at room temperature. Inorganic Chemistry, 2020, 59(6): 4024–4029

72 Kim Y I, Salim S, Huq M J, Visible-light photolysis of hydrogen iodide using sensitized layered semiconductor particles. Journal of the American Chemical Society, 1991, 113(25): 9561–9563

73 Miyata H, Sugahara Y, Kuroda K, Synthesis of a viologen–tetratitanate intercalation compound and its photochemical behaviour. Journal of the Chemical Society, Faraday Transactions 1. Physical Chemistry in Condensed Phases, 1988, 84(8): 2677–2682

74 Kaito R, Miyamoto N, Kuroda K, Intercalation of cationic phthalocyanines into layered titanates and control of the microstructures. Journal of Materials Chemistry, 2002, 12(12): 3463–3468

75 Miyamoto N, Kuroda K, Ogawa M. Visible light induced electron transfer and long-lived charge separated state in cyanine dye/layered titanate intercalation compounds. Journal of Physical Chemistry B, 2004, 108(14): 4268–4274

76 Ide Y, Ogawa M. Surface modification of a layered alkali titanate with organosilanes. Chemical Communications, 2003, 11(11): 1262

77 (Baitong) Tirayaphanitchkul C, (Jaa) Imwiset K, Ogawa M. Nanoarchitectonics through organic modification of oxide based layered materials: concepts, methods and functions. Bulletin of the Chemical Society of Japan, 2021, 94(2): 678–693

78 Ogawa M, Takizawa Y. Intercalation of tris(2, 2'-bipyridine)ruthenium(II) into a layered silicate, magadiite, with the aid of a crown ether. Journal of Physical Chemistry B, 1999, 103(24): 5005–5009

79 Ogawa M, Takizawa Y. One pot synthesis of layered tetratitanate-organic intercalation compounds with the aid of macrocyclic compounds. Molecular Crystals and Liquid Crystals Science and Technology Section A, Molecular Crystals and Liquid Crystals, 2000, 341(2): 357–362

80 Hsu C Y, Chiu T C, Shih M H, Effect of electron density of Pt catalysts supported on alkali titanate nanotubes in cinnamaldehyde hydrogenation. Journal of Physical Chemistry C, 2010, 114(10): 4502–4510

81 Marques T M F, Ferreira O P, da Costa J A P, Study of the growth of CeO₂ nanoparticles onto titanate nanotubes. Journal of Physics and Chemistry of Solids, 2015, 87: 213–220

82 Machida M, Ma X, Taniguchi H, Pillaring and photocatalytic property of partially substituted layered titanates, Na₂Ti_3−xM_xO₇ and K₂Ti_4−xM_xO₉ (M=Mn, Fe, Co, Ni, Cu). Journal of Molecular Catalysis A Chemical, 2000, 155(1–2): 131–142

83 Jiang F, Zheng Z, Xu Z, Preparation and characterization of SiO₂-pillared H₂Ti₄O₉ and its photocatalytic activity for methylene blue degradation. Journal of Hazardous Materials, 2009, 164(2–3): 1250–1256

84 Uchida S, Yamamoto Y, Fujishiro Y, Intercalation of titanium oxide in layered H₂Ti₄O₉ and H₄Nb₆O₁₇ and photocatalytic water cleavage with H₂Ti₄O₉/(TiO₂, Pt) and H₄Nb₆O₁₇/(TiO₂, Pt) nanocomposites. Journal of the Chemical Society, Faraday Transactions, 1997, 93(17): 3229–3234

85 Ogura S, Kohno M, Sato K, Effects of RuO₂ on activity for water decomposition of a RuO₂/Na₂Ti₃O₇ photocatalyst with a zigzag layer structure. Journal of Materials Chemistry, 1998, 8(11): 2335–2337

86 Harsha N, Krishna K V S, Renuka N K, Facile synthesis of γ-Fe₂O₃ nanoparticles integrated H₂Ti₃O₇ nanotubes structure as a magnetically recyclable dye-removal catalyst. RSC Advances, 2015, 5(38): 30354–30362

87 Lin B, Zhou Y, He L, Mesoporous CdS-pillared H₂Ti₃O₇ nanohybrids with efficient photocatalytic activity. Journal of Physics and Chemistry of Solids, 2015, 79: 66–71

88 Feist T P, Davies P K. The soft chemical synthesis of TiO₂ (B) from layered titanates. Journal of Solid State Chemistry, 1992, 101(2): 275–295

89 Zhu H Y, Lan Y, Gao X P, Phase transition between nanostructures of titanate and titanium dioxides via simple wet-chemical reactions. Journal of the American Chemical Society, 2005, 127(18): 6730–6736

90 Zou C, Zhao X, Xu Y. One-dimensional zirconium-doped titanate nanostructures for rapid and capacitive removal of multiple heavy metal ions from water. Dalton Transactions (Cambridge, England), 2018, 47(14): 4909–4915

91 Sirinakorn T T, Bureekaew S, Ogawa M. Layered titanates (Na₂Ti₃O₇ and Cs₂Ti₅O₁₁) as very high capacity adsorbents of cadmium(II). Bulletin of the Chemical Society of Japan, 2019, 92(1): 1–6

92 Tip Sirinakorn T, Bureekaew S, Ogawa M. Highly efficient indium(III) collection from water by a reaction with a layered titanate (Na₂Ti₃O₇). European Journal of Inorganic Chemistry, 2018, 2018(34): 3835–3839

93 Shibata M, Kudo A, Tanaka A, Photocatalytic activities of layered titanium compounds and their derivatives for H₂ evolution from aqueous methanol solution. Chemistry Letters, 1987, 16(6): 1017–1018

94 Kudo A, Kondo T. Photoluminescent and photocatalytic properties of layered caesium titanates, Cs₂Ti_nO_2n+1 (n=2, 5, 6). Journal of Materials Chemistry, 1997, 7: 777–780

95 Esmat M, Farghali A A, El-Dek S I, Conversion of a 2D lepidocrocite-type layered titanate into its 1D nanowire form with enhancement of cation exchange and photocatalytic performance. Inorganic Chemistry, 2019, 58(12): 7989–7996

96 Hosogi Y, Kato H, Kudo A. Photocatalytic activities of layered titanates and niobates ion-exchanged with Sn²⁺ under visible light irradiation. Journal of Physical Chemistry C, 2008, 112(45): 17678–17682

97 Lin C H, Chao J H, Tsai W J, Effects of electron charge density and particle size of alkali metal titanate nanotube-supported Pt photocatalysts on production of H₂ from neat alcohol. Physical Chemistry Chemical Physics, 2014, 16(43): 23743–23753

98 Hong S W, Kim A, Choi J H, Intercalation of conjugated polyelectrolytes in layered titanate nanosheets for enhancement in photocatalytic activity. Journal of Solid State Chemistry, 2019, 269: 291–296

99 Ogawa M, Morita M, Igarashi S, A green synthesis of a layered titanate, potassium lithium titanate; lower temperature solid-state reaction and improved materials performance. Journal of Solid State Chemistry, 2013, 206: 9–13

100 Escobedo Bretado M A, González Lozano M A, Collins Martínez V, Synthesis, characterization and photocatalytic evaluation of potassium hexatitanate (K₂Ti₆O₁₃) fibers. International Journal of Hydrogen Energy, 2019, 44(24): 12470–12476

101 Yoshida H, Takeuchi M, Sato M, Potassium hexatitanate photocatalysts prepared by a flux method for water splitting. Catalysis Today, 2014, 232: 158–164

102 Soontornchaiyakul W, Fujimura T, Yano N, Photocatalytic hydrogen evolution over exfoliated Rh-doped titanate nanosheets. ACS Omega, 2020, 5(17): 9929–9936

103 Khan S, Ikari H, Suzuki N, One-pot synthesis of anatase, rutile-decorated hydrogen titanate nanorods by yttrium doping for solar H₂ production. ACS Omega, 2020, 5(36): 23081–23089

104 Liu G, Wang L, Sun C, Band-to-band visible-light photon excitation and photoactivity induced by homogeneous nitrogen doping in layered titanates. Chemistry of Materials, 2009, 21(7): 1266–1274

105 Esmat M, El-Hosainy H, Tahawy R, Nitrogen doping-mediated oxygen vacancies enhancing co-catalyst-free solar photocatalytic H₂ production activity in anatase TiO₂ nanosheet assembly. Applied Catalysis B: Environmental, 2021, 285: 119755

106 Li P, Cao Q, Zheng D, Synthesis of mesoporous TiO₂-B nanobelts with highly crystalized walls toward efficient H₂ evolution. Nanomaterials (Basel, Switzerland), 2019, 9(7): 919

107 Chen W, Dosado A G, Chan A, Highly reactive anatase nanorod photocatalysts synthesized by calcination of hydrogen titanate nanotubes: effect of calcination conditions on photocatalytic performance for aqueous dye degradation and H₂ production in alcohol-water mixtures. Applied Catalysis A, General, 2018, 565: 98–118

108 Wang C, Zhang X, Zhang Y, Hydrothermal growth of layered titanate nanosheet arrays on titanium foil and their topotactic transformation to heterostructured TiO₂ photocatalysts. Journal of Physical Chemistry C, 2011, 115(45): 22276–22285

109 Wang C, Zhang X, Wei Y, Correlation between band alignment and enhanced photocatalysis: a case study with anatase/TiO₂(B) nanotube heterojunction. Dalton Transactions (Cambridge, England), 2015, 44(29): 13331–13339

110 Li Y, Wang C, Song M, TiO_2–x/CoO_x photocatalyst sparkles in photothermocatalytic reduction of CO₂ with H₂O steam. Applied Catalysis B: Environmental, 2019, 243: 760–770

111 Liu H, Lin B, He L, Mesoporous cobalt-intercalated layered tetratitanate for efficient visible-light photocatalysis. Chemical Engineering Journal, 2013, 215–216: 396–403

112 Cui W, Ma S, Liu L, Photocatalytic activity of Cd_1–xZn_xS/K₂Ti₄O₉ for Rhodamine B degradation under visible light irradiation. Applied Surface Science, 2013, 271: 171–181

113 Camposeco R, Castillo S, Rodriguez-González V, Promotional effect of Rh nanoparticles on WO₃/TiO₂ titanate nanotube photocatalysts for boosted hydrogen production. Journal of Photochemistry and Photobiology A, Chemistry, 2018, 353: 114–121

114 Yousef A, Barakat N A M, Khalil K A, Photocatalytic release of hydrogen from ammonia borane-complex using Ni(0)-doped TiO₂/C electrospun nanofibers. Colloids and Surfaces A, Physicochemical and Engineering Aspects, 2012, 410: 59–65

115 Nirmala R, Kim H Y, Yi C, Barakat N A M, Electrospun nickel doped titanium dioxide nanofibers as an effective photocatalyst for the hydrolytic dehydrogenation of ammonia borane. International Journal of Hydrogen Energy, 2012, 37(13): 10036–10045

116 Simagina V I, Komova O V, Ozerova A M, TiO₂-based photocatalysts for controllable hydrogen evolution from ammonia borane. Catalysis Today, 2020, online, doi:10.1016/j.cattod.2020.04.070

117 Zaki A H, Shalan A E, El-Shafeay A, Acceleration of ammonium phosphate hydrolysis using TiO₂ microspheres as a catalyst for hydrogen production. Nanoscale Advances, 2020, 2(5): 2080–2086

118 Barakat N A M, Zaki A H, Ahmed E, Fe_xCo_1−x-doped titanium oxide nanotubes as effective photocatalysts for hydrogen extraction from ammonium phosphate. International Journal of Hydrogen Energy, 2018, 43(16): 7990–7997

119 Wu Y, Sun Y, Fu W, Graphene-based modulation on the growth of urchin-like Na₂Ti₃O₇ microspheres for photothermally enhanced H₂ generation from ammonia borane. ACS Applied Nano Materials, 2020, 3(3): 2713–2722

120 Park H, Ou H H, Colussi A J, Artificial photosynthesis of C1–C3 hydrocarbons from water and CO₂ on titanate nanotubes decorated with nanoparticle elemental copper and CdS quantum dots. Journal of Physical Chemistry A, 2015, 119(19): 4658–4666

121 Wei Z, Kowalska E, Wang K, Enhanced photocatalytic activity of octahedral anatase particles prepared by hydrothermal reaction. Catalysis Today, 2017, 280: 29–36

122 Li Q, Kako T, Ye J. Facile ion-exchanged synthesis of Sn²⁺ incorporated potassium titanate nanoribbons and their visible-light-responded photocatalytic activity. International Journal of Hydrogen Energy, 2011, 36(8): 4716–4723

123 Ide Y, Shirae W, Takei T, Merging cation exchange and photocatalytic charge separation efficiency in an anatase/K₂Ti₄O₉ nanobelt heterostructure for metal ions fixation. Inorganic Chemistry, 2018, 57(10): 6045–6050

124 Ding J, Ming J, Lu D, Study of the enhanced visible-light-sensitive photocatalytic activity of Cr₂O₃^– loaded titanate nanosheets for Cr(VI) degradation and H₂ generation. Catalysis Science & Technology, 2017, 7(11): 2283–2297

125 Xue J, Long L, Zhang L, Enhanced H₂ evolution and the interfacial electron transfer mechanism of titanate nanotube sensitized with CdS quantum dots and graphene quantum dots. International Journal of Hydrogen Energy, 2020, 45(11): 6476–6486

126 Dosado A G, Chen W, Chan A, Novel Au/TiO₂ photocatalysts for hydrogen production in alcohol-water mixtures based on hydrogen titanate nanotube precursors. Journal of Catalysis, 2015, 330: 238–254

127 Wang H, Hu X, Ma Y, Nitrate-group-grafting-induced assembly of rutile TiO₂ nanobundles for enhanced photocatalytic hydrogen evolution. Chinese Journal of Catalysis, 2020, 41(1): 95–102

128 Dostanić J, Lončarević D, Pavlović V B, Efficient photocatalytic hydrogen production over titanate/titania nanostructures modified with nickel. Ceramics International, 2019, 45(15): 19447–19455

129 Huang J, Jiang Y, Li G, Hetero-structural NiTiO₃/TiO₂ nanotubes for efficient photocatalytic hydrogen generation. Renewable Energy, 2017, 111: 410–415

130 Majeed I, Nadeem M A, Kanodarwala F K, Controlled synthesis of TiO₂ nanostructures: exceptional hydrogen production in alcohol-water mixtures over Cu(OH)₂-Ni(OH)₂/TiO₂ nanorods. ChemistrySelect, 2017, 2(25): 7497–7507

131 Crake A, Christoforidis K C, Gregg A, The effect of materials architecture in TiO₂/MOF composites on CO₂ photoreduction and charge transfer. Small, 2019, 15(11): 1805473

132 Li J, Tang Z, Zhang Z. H-titanate nanotube: a novel lithium intercalation host with large capacity and high rate capability. Electrochemistry Communications, 2005, 7(1): 62–67

133 Chiba K, Kijima N, Takahashi Y, Synthesis, structure, and electrochemical Li-ion intercalation properties of Li₂Ti₃O₇ with Na₂Ti₃O₇-type layered structure. Solid State Ionics, 2008, 178(33–34): 1725–1730

134 Senguttuvan P, Rousse G, Seznec V, Na₂Ti₃O₇: lowest voltage ever reported oxide insertion electrode for sodium ion batteries. Chemistry of Materials, 2011, 23(18): 4109–4111