Review: Oxygen-deficient tungsten oxides
Source abstract
Abstract
Oxygen-deficient/non-stoichiometric tungsten oxides are a distinct class between two only stoichiometric tungsten oxides, i.e., WO3 and WO2. The WO3 could be termed as a parent structure while understanding the non-stoichiometric tungsten oxides. The oxygen vacancies (Ovacs) induced in the parent (WO3) structures cause the re-adjustment of atomic arrangement to compensate for the oxygen deficiency and follow the crystal chemistry. The degree of Ovacs determines the range of WO3-x. The W18O49 (WO2.722) is the highest oxygen-deficient stable phase. These non-stoichiometric oxides proved superior to WO3 for various applications. Thus, the composition, chemistry, crystallography, synthesis, and formation mechanisms of such materials have been elaborated. Further, the superiority of the materials in view of few applications is well discussed. Finally, the importance of non-stoichiometry/Ovacs in metal oxides for various functional applications can be understood.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Transition Metal Oxide Nanomaterials · Gas Sensing Nanomaterials and Sensors · Ga2O3 and related materials
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (100+)
Show source-provided references
1. Zheng H, Ou JZ, Strano MS et al (2011) Nanostructured tungsten oxide–properties, synthesis, and applications. Adv Funct Mater 21:2175–219610.1002/adfm.201002477 ↗
2. Bandi S, Vidyasagar D, Adil S et al (2020) Crystallite size induced bandgap tuning in WO3 derived from nanocrystalline tungsten. Scr Mater 176:47–52. https://doi.org/10.1016/j.scriptamat.2019.09.03210.1016/j.scriptamat.2019.09.032 ↗
3. Khoo E, Lee PS, Ma J (2010) Electrophoretic deposition (EPD) of WO3 nanorods for electrochromic application. J Eur Ceram Soc 30:1139–1144. https://doi.org/10.1016/j.jeurceramsoc.2009.05.01410.1016/j.jeurceramsoc.2009.05.014 ↗
4. Tilley RJD (1970) The formation of shear structures in sub-stoichiometric tungsten trioxide. Mater Res Bull 5:813–823. https://doi.org/10.1016/0025-5408(70)90032-210.1016/0025-5408(70)90032-2 ↗
5. Hu R, Wu H, Hong K (2007) Growth of uniform tungsten oxide nanowires with small diameter via a two-step heating process. J Cryst Growth 306:395–399. https://doi.org/10.1016/j.jcrysgro.2007.05.00710.1016/j.jcrysgro.2007.05.007 ↗
6. Bursill LA (1983) Structure of small defects in nonstoichiometric WO3−x. J Solid State Chem 48:256–271. https://doi.org/10.1016/0022-4596(83)90081-610.1016/0022-4596(83)90081-6 ↗
7. Migas DB, Shaposhnikov VL, Rodin VN, Borisenko VE (2010) Tungsten oxides. I. Effects of oxygen vacancies and doping on electronic and optical properties of different phases of WO3. J Appl Phys 108:093713. https://doi.org/10.1063/1.350568810.1063/1.3505688 ↗
8. Migas DB, Shaposhnikov VL, Borisenko VE (2010) Tungsten oxides. II. The metallic nature of Magnéli phases. J Appl Phys 108:093714. https://doi.org/10.1063/1.350568910.1063/1.3505689 ↗
9. Wang F, Di Valentin C, Pacchioni G (2011) Semiconductor-to-metal transition in WO3−x: nature of the oxygen vacancy. Phys Rev B 84:073103. https://doi.org/10.1103/PhysRevB.84.07310310.1103/PhysRevB.84.073103 ↗
10. Srivastav AK, Basu J, Kashyap S et al (2016) Crystallographic-shear-phase-driven W 18 O 49 nanowires growth on nanocrystalline W surfaces. Scr Mater 115:28–32. https://doi.org/10.1016/j.scriptamat.2015.12.03710.1016/j.scriptamat.2015.12.037 ↗
11. Zhang L, Wang H, Liu J et al (2020) Nonstoichiometric tungsten oxide: structure, synthesis, and applications. J Mater Sci Mater Electron 31:861–873. https://doi.org/10.1007/s10854-019-02596-z10.1007/s10854-019-02596-z ↗
12. Cora F, Stachiotti MG, Catlow CRA, Rodriguez CO (1997) Transition metal oxide chemistry: electronic structure study of WO3, ReO3, and NaWO3. J Phys Chem B 101:3945–3952. https://doi.org/10.1021/Jp963724z10.1021/Jp963724z ↗
13. Islam MA, Rondinelli JM, Spanier JE (2012) Normal mode determination of perovskite crystal structures with octahedral rotations: theory and applications. J Phys Condens Matter 25:175902. https://doi.org/10.1088/0953-8984/25/17/17590210.1088/0953-8984/25/17/175902 ↗
14. Guo T, Yao M-S, Lin Y-H, Nan C-W (2015) A comprehensive review on synthesis methods for transition-metal oxide nanostructures. CrystEngComm 17:3551–3585. https://doi.org/10.1039/C5CE00034C10.1039/C5CE00034C ↗
15. Tanisaki S (1960) On the transition of tungsten trioxide below room temperature. J Phys Soc Japan 15:566–573. https://doi.org/10.1143/JPSJ.15.56610.1143/JPSJ.15.566 ↗
16. Loopstra BO, Rietveld HM (1969) Further refinement of the structure of WO 3. Acta Crystallogr Sect B Struct Crystallogr Cryst Chem 25:1420–1421. https://doi.org/10.1107/S056774086900414610.1107/S0567740869004146 ↗
17. Woodward PM, Sleight AW, Vogt T (1997) Ferroelectric tungsten trioxide. J Solid State Chem 131:9–17. https://doi.org/10.1006/jssc.1997.726810.1006/jssc.1997.7268 ↗
18. Polaczek A, Pekala M, Obuszko Z (1994) Magnetic susceptibility and thermoelectric power of tungsten intermediary oxides. J Phys Condens Matter 6:7909–7919. https://doi.org/10.1088/0953-8984/6/39/01110.1088/0953-8984/6/39/011 ↗
19. Allpress JG, Tilley RJD, Sienko MJ (1971) Examination of substoichiometric WO3 crystals by electron microscopy. J Solid State Chem 3:440–451. https://doi.org/10.1016/0022-4596(71)90083-110.1016/0022-4596(71)90083-1 ↗
20. Iijima S (1975) High-resolution electron microscopy of crystallographic shear structures in tungsten oxides. J Solid State Chem 14:52–65. https://doi.org/10.1016/0022-4596(75)90361-810.1016/0022-4596(75)90361-8 ↗
21. Sundberg M, Tilley RJD (1974) An electron microscope study of some nonstoichiometric oxides. J Solid State Chem 11:150–160. https://doi.org/10.1016/0022-4596(74)90110-810.1016/0022-4596(74)90110-8 ↗
22. Tilley RJD (1995) The crystal chemistry of the higher tungsten oxides. Chem Non-Sag Tungsten 13:93–109. https://doi.org/10.1016/B978-0-08-042676-1.50012-910.1016/B978-0-08-042676-1.50012-9 ↗
23. Smith AM, Kast MG, Nail BA et al (2014) A planar-defect-driven growth mechanism of oxygen deficient tungsten oxide nanowires. J Mater Chem A 2:6121–6129. https://doi.org/10.1039/C3TA14163B10.1039/C3TA14163B ↗
24. Magnéli A (1964) Informal Proc. Buhl Intern. Conf. Mater. Pittsburgh. pp. 109–122
25. Sundbeg M (1976) The crystal and defect structures of W25O73, a member of the homologous series WnO3n-2. Acta Cryst B 32:2144–2149. https://doi.org/10.1107/S056774087600728010.1107/S0567740876007280 ↗
26. Van Landuyt J (1974) Shear structures and crystallographic shear propagation. Le J Phys Colloq 35:53–63. https://doi.org/10.1051/jphyscol:197470410.1051/jphyscol:1974704 ↗
27. Gadó P (1965) X-ray powder diffraction study of the WO3⇌W20O58 shear transformation. Acta Phys Acad Sci Hungaricae 18:111–117. https://doi.org/10.1007/BF0315798210.1007/BF03157982 ↗
28. Wadsley AD, Andersson S (1966) Crystallographic shear and diffusion paths in certain higher oxides of niobium, tungsten, molybdenum and titanium. Nature 211:581–583. https://doi.org/10.1038/211581a010.1038/211581a0 ↗
29. Anderson JS, Hyde BG (1967) On the possible role of dislocations in generating ordered and disordered shear structures. J Phys Chem Solids 28:1393–1408. https://doi.org/10.1016/0022-3697(67)90268-510.1016/0022-3697(67)90268-5 ↗
30. Van Landuyt J, Amelinckx S (1973) On the generation mechanism for shear planes in shear structures. J Solid State Chem 6:222–229. https://doi.org/10.1016/0022-4596(73)90185-010.1016/0022-4596(73)90185-0 ↗
31. Pickering R, Tilley RJD (1976) An electron microscope study of tungsten oxides in the composition range WO2.90–WO2.72. J Solid State Chem 16:247–255. https://doi.org/10.1016/0022-4596(76)90039-610.1016/0022-4596(76)90039-6 ↗
32. Dobson MM, Tilley RJD (1988) A new pseudo–binary tungsten oxide, W17O47. Acta Crystallogr Sect B 44:474–480. https://doi.org/10.1107/S010876818800438010.1107/S0108768188004380 ↗
33. Booth J, Ekström T, Iguchi E, Tilley RJD (1982) Notes on phases occurring in the binary tungsten-oxygen system. J Solid State Chem 41:293–307. https://doi.org/10.1016/0022-4596(82)90149-910.1016/0022-4596(82)90149-9 ↗
34. Lundberg M, Sundberg M, Magnéli A (1982) The “pentagonal column” as a building unit in crystal and defect structures of some groups of transition metal compounds. J Solid State Chem 44:32–40. https://doi.org/10.1016/0022-4596(82)90398-X10.1016/0022-4596(82)90398-X ↗
35. Su C, Lin C, Cheng C (2005) A modified plasma arc gas condensation technique to synthesize nanocrystalline tungsten oxide powders. Mater Trans 46:1016–1020. https://doi.org/10.2320/matertrans.46.101610.2320/matertrans.46.1016 ↗
36. Dellasega D, Pietralunga SM, Pezzoli A et al (2015) Tungsten oxide nanowires grown on amorphous-like tungsten films. Nanotechnology 26:365601. https://doi.org/10.1088/0957-4484/26/36/36560110.1088/0957-4484/26/36/365601 ↗
37. Seelaboyina R (2016) Tungsten oxide nanowire synthesis from amorphous-like tungsten films. Nanotechnology 27:112502. https://doi.org/10.1088/0957-4484/27/11/11250210.1088/0957-4484/27/11/112502 ↗
38. Yu HK, Lee J (2015) Growth mechanism of metal-oxide nanowires synthesized by electron beam evaporation: a self-catalytic vapor-liquid-solid process. Sci Rep 4:6589. https://doi.org/10.1038/srep0658910.1038/srep06589 ↗
39. Chen C-H, Wang S, Ko R et al (2006) The influence of oxygen content in the sputtering gas on the self-synthesis of tungsten oxide nanowires on sputter-deposited tungsten films. Nanotechnology 17:217–223. https://doi.org/10.1088/0957-4484/17/1/03610.1088/0957-4484/17/1/036 ↗
40. Jin YZ, Zhu YQ, Whitby RLD et al (2004) Simple approaches to quality large-scale tungsten oxide nanoneedles. J Phys Chem B 108:15572–15577. https://doi.org/10.1021/jp048596q10.1021/jp048596q ↗
41. Gu G, Zheng B, Han WQ et al (2002) Tungsten oxide nanowires on tungsten. Nano Lett 2:849–851. https://doi.org/10.1021/nl025618g10.1021/nl025618g ↗
42. Shen Z, Peng Z, Zhao Z, Fu X (2018) Nonlinear current-voltage characteristics of WO3-x nano-/micro-rods. Solid State Sci 78:126–132. https://doi.org/10.1016/j.solidstatesciences.2018.03.00210.1016/j.solidstatesciences.2018.03.002 ↗
43. Yu W, Shen Z, Peng F et al (2019) Improving gas sensing performance by oxygen vacancies in sub-stoichiometric WO 3–x. RSC Adv 9:7723–7728. https://doi.org/10.1039/C9RA00116F10.1039/C9RA00116F ↗
44. Qian J, Peng Z, Shen Z et al (2016) Positive impedance humidity sensors via single-component materials. Sci Rep 6:25574. https://doi.org/10.1038/srep2557410.1038/srep25574 ↗
45. Shi S, Xue X, Feng P et al (2008) Low-temperature synthesis and electrical transport properties of W18O49 nanowires. J Cryst Growth 310:462–466. https://doi.org/10.1016/j.jcrysgro.2007.10.03810.1016/j.jcrysgro.2007.10.038 ↗
46. Zhou J, Gong L, Deng SZ et al (2005) Growth and field-emission property of tungsten oxide nanotip arrays. Appl Phys Lett 87:223108. https://doi.org/10.1063/1.213600610.1063/1.2136006 ↗
47. Chi L, Xu N, Deng S et al (2006) An approach for synthesizing various types of tungsten oxide nanostructure. Nanotechnology 17:5590–5595. https://doi.org/10.1088/0957-4484/17/22/01110.1088/0957-4484/17/22/011 ↗
48. Hong K, Xie M, Wu H (2006) Tungsten oxide nanowires synthesized by a catalyst-free method at low temperature. Nanotechnology 17:4830–4833. https://doi.org/10.1088/0957-4484/17/19/00810.1088/0957-4484/17/19/008 ↗
49. Senthil K, Yong K (2007) Growth and characterization of stoichiometric tungsten oxide nanorods by thermal evaporation and subsequent annealing. Nanotechnology 18:395604. https://doi.org/10.1088/0957-4484/18/39/39560410.1088/0957-4484/18/39/395604 ↗
50. Luo JY, Chen F, Cao Z et al (2015) Complex three-dimensional tungsten oxide nanowire networks: controllable synthesis and growth mechanism. CrystEngComm 17:889–894. https://doi.org/10.1039/C4CE01715C10.1039/C4CE01715C ↗
51. Cheong FC, Varghese B, Zhu Y et al (2007) WO3–x Nanorods synthesized on a thermal hot plate. J Phys Chem C 111:17193–17199. https://doi.org/10.1021/jp074569z10.1021/jp074569z ↗
52. Kojima Y, Kasuya K, Nagato K et al (2008) Solid-phase growth mechanism of tungsten oxide nanowires synthesized on sputtered tungsten film. J Vac Sci Technol B Microelectron Nanom Struct 26:1942–1947. https://doi.org/10.1116/1.299078310.1116/1.2990783 ↗
53. Qin Y, Xie W, Liu Y, Ye Z (2016) Thermal-oxidative growth of aligned W18O49 nanowire arrays for high performance gas sensor. Sens Actuators B Chem 223:487–495. https://doi.org/10.1016/j.snb.2015.09.11310.1016/j.snb.2015.09.113 ↗
54. Spanu D, Recchia S, Schmuki P, Altomare M (2020) Thermal-oxidative growth of substoichiometric WO3–x nanowires at mild conditions. Phys status solidi Rapid Res Lett 14:2000235. https://doi.org/10.1002/pssr.20200023510.1002/pssr.202000235 ↗
55. Zhu L, Zhang Z, Ke X et al (2018) WO2 triggered nucleation and growth of ultra-long W18O49 structures, from nanobundles to single-crystalline microrod. Acta Mater 148:55–62. https://doi.org/10.1016/j.actamat.2018.01.03210.1016/j.actamat.2018.01.032 ↗
56. Pu W, Song Z, Yan J et al (2019) Preparation of oxygen-deficient 2D WO3−x nanoplates and their adsorption behaviors for organic pollutants: equilibrium and kinetics modeling. J Mater Sci 54:12463–12475. https://doi.org/10.1007/s10853-019-03780-610.1007/s10853-019-03780-6 ↗
57. Hong K, Xie M, Hu R, Wu H (2007) Synthesizing tungsten oxide nanowires by a thermal evaporation method. Appl Phys Lett 90:173121. https://doi.org/10.1063/1.273417510.1063/1.2734175 ↗
58. Hong K, Xie M, Hu R, Wu H (2008) Diameter control of tungsten oxide nanowires as grown by thermal evaporation. Nanotechnology 19:085604. https://doi.org/10.1088/0957-4484/19/8/08560410.1088/0957-4484/19/8/085604 ↗
59. Chi LF, Deng SZ, Xu NS et al (2009) The study of optimizing growth conditions for improving field emission property of W18O49 nanorod arrays. J Phys Conf Ser 188:012021. https://doi.org/10.1088/1742-6596/188/1/01202110.1088/1742-6596/188/1/012021 ↗
60. Van Hieu N, Van Vuong H, Van Duy N, Hoa ND (2012) A morphological control of tungsten oxide nanowires by thermal evaporation method for sub-ppm NO2 gas sensor application. Sens Actuators B Chem 171–172:760–768. https://doi.org/10.1016/j.snb.2012.05.06910.1016/j.snb.2012.05.069 ↗
61. Vaddiraju S, Chandrasekaran H, Sunkara MK (2003) Vapor Phase synthesis of tungsten nanowires. J Am Chem Soc 125:10792–10793. https://doi.org/10.1021/ja035868e10.1021/ja035868e ↗
62. Thangala J, Vaddiraju S, Bogale R et al (2007) Large-scale, hot-filament-assisted synthesis of tungsten oxide and related transition metal oxide nanowires. Small 3:890–896. https://doi.org/10.1002/smll.20060068910.1002/smll.200600689 ↗
63. Thangala J, Vaddiraju S, Malhotra S et al (2009) A hot-wire chemical vapor deposition (HWCVD) method for metal oxide and their alloy nanowire arrays. Thin Solid Films 517:3600–3605. https://doi.org/10.1016/j.tsf.2009.01.05110.1016/j.tsf.2009.01.051 ↗
64. Hsieh YT, Chen US, Hsueh SH et al (2011) Rapid formation of tungsten oxide nanobundles with controllable morphology. Appl Surf Sci 257:3504–3509. https://doi.org/10.1016/j.apsusc.2010.11.06310.1016/j.apsusc.2010.11.063 ↗
65. Devan RS, Patil RA, Lin J, Ma Y (2012) One-dimensional metal-oxide nanostructures: recent developments in synthesis, characterization, and applications. Adv Funct Mater 22:3326–3370. https://doi.org/10.1002/adfm.20120100810.1002/adfm.201201008 ↗
66. Bandi S, Naga Suresh N, Bhoyar T, Srivastav AK (2020) WO3.1/3H2O nanorods/nanoplates: growth mechanism and CO2 uptake. Materialia 14:100943. https://doi.org/10.1016/j.mtla.2020.10094310.1016/j.mtla.2020.100943 ↗
67. Sun S, Zhao Y, Xia Y et al (2008) Bundled tungsten oxide nanowires under thermal processing. Nanotechnology 19:305709. https://doi.org/10.1088/0957-4484/19/30/30570910.1088/0957-4484/19/30/305709 ↗
68. Choi HG, Jung YH, Kim DK (2005) Solvothermal synthesis of tungsten oxide nanorod/nanowire/nanosheet. J Am Ceram Soc 88:1684–1686. https://doi.org/10.1111/j.1551-2916.2005.00341.x10.1111/j.1551-2916.2005.00341.x ↗
69. Lee K, Seo WS, Park JT (2003) Synthesis and optical properties of colloidal tungsten oxide nanorods. J Am Chem Soc 125:3408–3409. https://doi.org/10.1021/ja034011e10.1021/ja034011e ↗
70. Xu X, Fang G, Shang J et al (2020) LSPR-excited obvious hydrogen yield enhancement for TiO2:Er3+, Yb3+@W18O49 quasi-core/shell heterostructure. J Mater Sci 55:2958–2966. https://doi.org/10.1007/s10853-019-04168-210.1007/s10853-019-04168-2 ↗
71. Rout CS, Govindaraj A, Rao CNR (2006) High-sensitivity hydrocarbon sensors based on tungsten oxide nanowires. J Mater Chem 16:3936–3941. https://doi.org/10.1039/b607012b10.1039/b607012b ↗
72. Zhao YM, Hu WB, Xia YD et al (2007) Preparation and characterization of tungsten oxynitride nanowires. J Mater Chem 17:4436–4440. https://doi.org/10.1039/b709486h10.1039/b709486h ↗
73. Zhao YM, Zhu YQ (2009) Room temperature ammonia sensing properties of W18O49 nanowires. Sens Actuators B Chem 137:27–31. https://doi.org/10.1016/j.snb.2009.01.00410.1016/j.snb.2009.01.004 ↗
74. Xi G, Ouyang S, Li P et al (2012) Ultrathin W18O49 nanowires with diameters below 1 nm: synthesis, near-infrared absorption, photoluminescence, and photochemical reduction of carbon dioxide. Angew Chemie Int Ed 51:2395–2399. https://doi.org/10.1002/anie.20110768110.1002/anie.201107681 ↗
75. Lu C-H, Hon MH, Kuan C-Y, Leu I-C (2015) Controllable synthesis of W18O49 nanowire arrays and their application in electrochromic devices. J Mater Sci 50:5739–5745. https://doi.org/10.1007/s10853-015-9119-510.1007/s10853-015-9119-5 ↗
76. Guo X, Qin X, Xue Z et al (2016) Morphology-controlled synthesis of WO2.72 nanostructures and their photocatalytic properties. RSC Adv 6:48537–48542. https://doi.org/10.1039/C6RA08551B10.1039/C6RA08551B ↗
77. Hai G, Huang J, Cao L et al (2017) Influence of oxygen deficiency on the synthesis of tungsten oxide and the photocatalytic activity for the removal of organic dye. J Alloys Compd 690:239–248. https://doi.org/10.1016/j.jallcom.2016.08.09910.1016/j.jallcom.2016.08.099 ↗
78. Zhou H, Shi Y, Dong Q et al (2014) Surface oxygen vacancy-dependent electrocatalytic activity of W18O49 nanowires. J Phys Chem C 118:20100–20106. https://doi.org/10.1021/jp504368v10.1021/jp504368v ↗
79. Li K, Shao Y, Yan H et al (2018) Lattice-contraction triggered synchronous electrochromic actuator. Nat Commun 9:4798. https://doi.org/10.1038/s41467-018-07241-710.1038/s41467-018-07241-7 ↗
80. Wang Y, Wang X, Xu Y et al (2017) Simultaneous synthesis of WO3−x quantum dots and bundle-like nanowires using a one-pot template-free solvothermal strategy and their versatile applications. Small 13:1–11. https://doi.org/10.1002/smll.20160368910.1002/smll.201603689 ↗
81. Sinha L, Shirage PM (2019) Surface oxygen vacancy formulated energy storage application: pseudocapacitor-battery trait of W18O49 nanorods. J Electrochem Soc 166:A3496–A3503. https://doi.org/10.1149/2.1251914jes10.1149/2.1251914jes ↗
82. Song K, Liu X, Tian C et al (2019) Oxygen defect-rich WO3-x nanostructures with high photocatalytic activity for dehydration of isopropyl alcohol to propylene. Surf Interfaces 14:245–250. https://doi.org/10.1016/j.surfin.2018.11.00210.1016/j.surfin.2018.11.002 ↗
83. Li J, Chen G, Yan J et al (2020) Solar-driven plasmonic tungsten oxides as catalyst enhancing ethanol dehydration for highly selective ethylene production. Appl Catal B Environ 264:118517. https://doi.org/10.1016/j.apcatb.2019.11851710.1016/j.apcatb.2019.118517 ↗
84. Cheng W, Ju Y, Payamyar P et al (2015) Large-area alignment of tungsten oxide nanowires over flat and patterned substrates for room-temperature gas sensing. Angew Chemie Int Ed 54:340–344. https://doi.org/10.1002/anie.20140861710.1002/anie.201408617 ↗
85. Gao X, Xiao F, Yang C et al (2013) Hydrothermal fabrication of W18O49 nanowire networks with superior performance for water treatment. J Mater Chem A 1:5831–5834. https://doi.org/10.1039/c3ta10724h10.1039/c3ta10724h ↗
86. Lou XW, Zeng HC (2003) An inorganic route for controlled synthesis of W18O49 nanorods and nanofibers in solution. Inorg Chem 42:6169–6171. https://doi.org/10.1021/ic034771q10.1021/ic034771q ↗
87. Bhuyan B, Paul B, Dhar SS, Vadivel S (2017) Facile hydrothermal synthesis of ultrasmall W18O49 nanoparticles and studies of their photocatalytic activity towards degradation of methylene blue. Mater Chem Phys 188:1–7. https://doi.org/10.1016/j.matchemphys.2016.12.03510.1016/j.matchemphys.2016.12.035 ↗
88. Guo C, Yin S, Huang Y et al (2011) Synthesis of W18O49 nanorod via ammonium tungsten oxide and its interesting optical properties. Langmuir 27:12172–12178. https://doi.org/10.1021/la202513q10.1021/la202513q ↗
89. Chen P, Qin M, Chen Z et al (2016) Solution combustion synthesis of nanosized WOx: characterization, mechanism and excellent photocatalytic properties. RSC Adv 6:83101–83109. https://doi.org/10.1039/C6RA12375A10.1039/C6RA12375A ↗
90. Chen P, Qin M, Zhang D et al (2015) Combustion synthesis and excellent photocatalytic degradation properties of W18O49. CrystEngComm 17:5889–5894. https://doi.org/10.1039/C5CE00995B10.1039/C5CE00995B ↗
91. Salkar AV, Fernandes RX, Bhosale SV, Morajkar PP (2019) NH- And CH-substituted ureas as self-assembly directing motifs for facile synthesis and electrocapacitive applications of advanced WO3- x one-dimensional nanorods. ACS Appl Energy Mater 2:8724–8736. https://doi.org/10.1021/acsaem.9b0170410.1021/acsaem.9b01704 ↗
92. Bao K, Zhang S, Ni P et al (2020) Convenient fabrication of carbon doped WO3−x ultrathin nanosheets for photocatalytic aerobic oxidation of amines. Catal Today 340:311–317. https://doi.org/10.1016/j.cattod.2018.11.01310.1016/j.cattod.2018.11.013 ↗
93. Zhu YQ, Hu W, Hsu WK et al (1999) Tungsten oxide tree-like structures. Chem Phys Lett 309:327–334. https://doi.org/10.1016/S0009-2614(99)00732-010.1016/S0009-2614(99)00732-0 ↗
94. Aǧıral A, Gardeniers JGE (2008) Synthesis and atmospheric pressure field emission operation of W 18 O 49 nanorods. J Phys Chem C 112:15183–15189. https://doi.org/10.1021/jp802756y10.1021/jp802756y ↗
95. Liu J, Zhao Y, Zhang Z (2003) Low-temperature synthesis of large-scale arrays of aligned tungsten oxide nanorods. J Phys Condens Matter 15:L453–L461. https://doi.org/10.1088/0953-8984/15/29/10110.1088/0953-8984/15/29/101 ↗
96. Sahle W (1982) Electron microscopy studies of W18O49. 2. Defects and disorder introduced by partial oxidation. J Solid State Chem 45:334–342. https://doi.org/10.1016/0022-4596(82)90179-710.1016/0022-4596(82)90179-7 ↗
97. Rothschild A, Sloan J, Tenne R (2000) Growth of WS2 nanotubes phases. J Am Chem Soc 122:5169–5179. https://doi.org/10.1021/ja994118v10.1021/ja994118v ↗
98. Fang Z, Jiao S, Kang Y et al (2017) Photothermal conversion of W18O49 with a tunable oxidation state. ChemistryOpen 6:261–265. https://doi.org/10.1002/open.20160014910.1002/open.201600149 ↗
99. Zhou R, Lin X, Xue D et al (2018) Enhanced H2 gas sensing properties by Pd-loaded urchin-like W18O49 hierarchical nanostructures. Sens Actuators B Chem 260:900–907. https://doi.org/10.1016/j.snb.2018.01.10410.1016/j.snb.2018.01.104 ↗
100. Shirke YM, Porel Mukherjee S (2017) Selective synthesis of WO3 and W18O49 nanostructures: ligand-free pH-dependent morphology-controlled self-assembly of hierarchical architectures from 1D nanostructure and sunlight-driven photocatalytic degradation. CrystEngComm 19:2096–2105. https://doi.org/10.1039/c6ce02518h10.1039/c6ce02518h ↗