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Broom-like and flower-like heterostructures of silver molybdate through pH controlled self assembly

Abstract

Silver molybdate microrods are self-assembled into micron sized, broom-like and flower-like structures. Our investigations indicate that through a simple hydrothermal process, large scale production of such structure is possible. Using ammonium molybdate and silver nitrate solutions as precursors, we were able to show that the self assembled architectures were dependent on the pH of the starting precursor material. To understand the formation and destructions of the flower-like morphology, a systematic broad range (from acidic to basic) of pH-controlled experiments were performed and its influence on the structure/microstructure of synthesized materials was investigated. Scanning electron microscopy studies revealed that the morphology and microstructure of the products varied significantly by changing pH values from 3 to 8 during mixing of the reactants. pH = 3 and 4 resulted in the self assembly of monoclinic Ag2(Mo2O7) microrods into broom-like structures, whereas pH = 5 resulted into the flower-like morphology of mixed phase of monoclinic and triclinic Ag2Mo2O7. We also found that increasing the pH after a certain threshold value (for example pH > 6) resulted in total collapse of the flower-like morphology. Further increase of the pH to 7 and 8 resulted, the formation of microparticles of Ag2MoO4. A tentative scheme based on the pH-driven evolution of the self-assembly has been given to explain the formation of the observed heterostructures. Preliminary electrical characterization of thin films of the flower-like structures rendered non-linear current–voltage (I–V) responses. We also observed a strong hysteresis in the I–V responses of the flower-like structures developed under high bias conditions.

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References

  1. Appell D (2002) Nanotechnology: wired for success. Nature 419:553–555

  2. Bazarov BG, Grossman VG, Klevtsova RF, Anshits G, Vereshchagina TA, Glinskaya LA, Tushinova YL, Fedorov KN, Bazarova ZG (2009) Crystal structure of binary molybdate Pr2Hf3(MoO4)9. J Struct Chem 50:566–569

  3. Bertoni MI, Kidner NJ, Mason TO, Albrecht TA, Sorensen EM, Poeppelmeier KR (2007) Electrical and optical characterization of Ag2V4O11 and Ag4V2O6F2. J Electroceram 18:189–195

  4. Bhattacharya S, Ghosh A (2005) Transport properties of AgI doped silver molybdate superionic glass-nanocomposites. J Phys Condens Matter 17:5655–5662

  5. Cheng L, Shao Q, Shao M, Wei X, Wu Z (2009) Photoswitches of one-dimensional Ag2MO4 (M = Cr, Mo, and W). J Phys Chem C 113:1764–1768

  6. Cui X, Yu SH, Li L, Biao L, Li H, Mo M, Liu XM (2004) Selective synthesis and characterization of single-crystal silver molybdate/tungstate nanowires by a hydrothermal process. Chem Eur J 10:218–223

  7. Dong F, Huang Y, Zou S, Liu J, Lee SC (2011) Ultrasonic spray pyrolysis fabrication of solid and hollow PbWO4 spheres with structure-directed photocatalytic activity. J Phys Chem C 115:241–247

  8. Driscoll S, Ozkan US (1994) Isotopic labeling studies on oxidative coupling of methane over alkali promoted molybdate catalysts. Stud Surf Sci Catal 82:367–375

  9. Ehrenberg E, Weitzely H, Heidy C, Fuessy H, Wltschekz G, Kroenerx T, van Tol J, Bonnet M (1997a) Magnetic phase diagrams of MnWO4. J Phys Condens Matter 9:3189–3203

  10. Ehrenberg H, Weitzel H, Paulus H, Wiesmann M, Wltschek G, Geselle M, Fuess H (1997b) Crystal structure and magnetic properties of CuMoO4 at low temperature (γ-phase). J Phys Chem Solids 58:153–160

  11. Feilchenfeld H, Siiman O (1986) Adsorption and aggregation kinetics and its fractal description for chromate, molybdate, and tungstate ions on colloidal silver from surface Raman spectra. J Phys Chem 90:4590–4599

  12. Goldberger J, He R, Zhang Y, Lee S, Yan H, Choi HJ, Yang P (2003) Single-crystal gallium nitride nanotubes. Nature 422:599–602

  13. Gulbinski W, Suszko T (2006) Thin films of MoO3–Ag2O binary oxides the high temperature lubricants. Wear 261:867–873

  14. Gulbinski W, Suszko T, Sienicki W, Warcholinski B (2003) Tribological properties of silver- and copper-doped transition metal oxide coatings. Wear 254:129–135

  15. Guo J, Zavalij P, Stanley WM (1995) Metastable hexagonal molybdates: hydrothermal preparation, structure, and reactivity. J Solid State Chem 117:323–332

  16. Holtz RD, Filho AGS, Brocchi M, Martins D, Durán N, Alves OL (2010) Development of nanostructured silver vanadates decorated with silver nanoparticles as a novel antibacterial agent. Nanotechnology 21:185102–185110

  17. Hu B, Mai L, Chen W, Yang F (2009) From MoO3 nanobelts to MoO2 nanorods: structure transformation and electrical transport. ACS Nano 3:478–482

  18. Ito T, Takagi H, Asano T (2009) Drastic and sharp change in color, shape, and magnetism in transition of CuMoO4 single crystals. Chem Mater 21:3376–3379

  19. Kozma P, Bajgar R, Kozma JP (2002) Radiation damage of PbWO4 crystals due to radiation by 60Co gamma-rays. Radiat Phys Chem 65:127–130

  20. Krol R, Liang Y, Schoonman J (2008) Solar hydrogen production with nanostructured metal oxides. J Mater Chem 18:2311–2320

  21. Li X, Zang J (2009) Facile hydrothermal synthesis of sodium tantalate (NaTaO3) nanocubes and high photocatalytic properties. J Phys Chem C 113:19411–19418

  22. Li Y, Qian F, Xiang J, Lieber CM (2006) Nanowire electronic and optoelectronic devices. Mater Today 9:18–27

  23. Liao HW, Wang YF, Liu XM, Li YD, Qian YT (2000) Hydrothermal preparation and characterization of luminescent CdWO4 nanorods. Chem Mater 12:2819–2821

  24. Lu J, Li Y, Shen E, Yuan M, Wang E, Hu C, Xu L (2004) Hydrothermal synthesis and crystal structure of a novel two-dimensional organic–inorganic hybrid copper molybdate with mixed organodiamine and dicarboxyl ligands. J Solid State Chem 177:1771–1775

  25. Machida N, Eckert H (1998) FT-IR, FT-Raman and 95MoMAS–NMR studies on the structure of ionically conducting glasses in the system AgI–Ag2O–MoO3. Solid State Ion 107:255–268

  26. Mai L, Xu L, Gao Q, Han C, Hu B, Pi Y (2010) Single-AgVO3 nanowire H2S sensor. Nano Lett 10:2604–2612

  27. Mougin O, Dubois JL, Mathieu F, Rousset A (2000) Metastable hexagonal vanadium molybdate study. J Solid State Chem 152:353–360

  28. Nagaraju G, Tharamani CN, Chandrappa GT, Livage J (2007) Hydrothermal synthesis of amorphous MoS2 nanofiber bundles via acidification of ammonium heptamolybdate tetrahydrate. Nanoscale Res Lett 2:461–468

  29. Newton MC, Leake SJ, Harder R, Robinson IK (2009) Three-dimensional imaging of strain in a single ZnO nanorod. Nat Mater 9:120–124

  30. Nyman M, Rodriguez MA, Rohwer LES, Martin JE, Waller M, Osterloh FE (2009) Unique LaTaO4 polymorph for multiple energy applications. Chem Mater 21:4731–4737

  31. Pan H, Feng YP (2008) Semiconductor nanowires and nanotubes: effects of size and surface-to-volume ratio. ACS Nano 2:2410–2414

  32. Pan GT, Lai MH, Juang RC, Chung TW, Yang TCK (2011) Preparation of visible-light-driven silver vanadates by a microwave- assisted hydrothermal method for the photodegradation of volatile organic vapors. Ind Eng Chem Res 50:2807–2814

  33. Panchal V, Garg N, Sharma SM (2006) Raman and X-ray diffraction investigations on BaMoO4 under high pressures. J Phys Condens Matter 18:3917–3929

  34. Qu W, Wlodarski W, Meyer JU (2000) Comparative study on micromorphology and humidity sensitive properties of thin-film and thick-film humidity sensors based on semiconducting MnWO4. Sens Actuators B64:76–82

  35. Readman JE, Lister SE, Peters L, Wright J, Evans JSO (2009) Direct synthesis of cubic ZrMo2O8 followed by ultrafast in situ powder diffraction. J Am Chem Soc 131:17560–17562

  36. Singh DP (2010) Synthesis and growth of ZnO nanowires. Sci Adv Mater 2:245–272

  37. Singh DP, Ali N (2010) Synthesis of TiO2 and CuO nanotubes and nanowires. Sci Adv Mater 2:295–335

  38. Singh DP, Polychronopoulou K, Rebholz C, Aouadi SM (2010) Room temperature synthesis and high temperature frictional study of silver vanadate nanorods. Nanotechnol 21:325601–325608

  39. Song RQ, Xu AW, Deng B, Fang YP (2005) Novel multilamellar mesostructured molybdenum oxide nanofibers and nanobelts: synthesis and characterization. J Phys Chem B 109:22758–22766

  40. Tian ZR, Voigt JA, Liu J, Mckenzie B, Mcdermott MJ, Rodriguez MA, Konishi H, Xu H (2003) Complex and oriented ZnO nanostructures. Nat Mater 2:821–826

  41. Tian H, Wachs IE, Briand LE (2005) Comparison of UV and visible Raman spectroscopy of bulk metal molybdate and metal vanadate catalysts. J Phys Chem B 109:23491–23499

  42. Van Uitert LG, Preziosi S (1962) Zinc tungstates for microwave maser applications. J Appl Phys 33:2908–2910

  43. Vijayaraghavan A, Kanzaki K, Suzuki S, Kobayashi Y, Inokawa H, Ono Y, Kar S, Ajayan PM (2005) Metal-semiconductor transition in single-walled carbon nanotubes induced by low-energy electron irradiation. Nano Lett 5:1575–1579

  44. Wang H, Medina FD, Zhou YD, Zhang QN (1992) Temperature dependence of the polarized Raman spectra of ZnWO4 single crystals. Phys Rev B 45:10356–10362

  45. Wang H, Medina FD, Liu D, Zhou YD (1994) The line shape and zero-phonon line of the luminescence spectrum from zinc tungstate single crystals. J Phys Condens Matter 6:5373–5386

  46. White CT, Todorov TN (2001) Quantum electronics: nanotubes go ballistic. Nature 411:649–651

  47. Wu J, Duan F, Zheng Y, Xie Y (2007) Synthesis of Bi2WO6 nanoplate-built hierarchical nest-like structures with visible-light-induced photocatalytic activity. J Phys Chem C 111:12866–12871

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Acknowledgements

This research is supported by the National Science Foundation (Award # CMMI-0653986), the U.S. Department of the ARMY (Award # W911NF-08-1-0460), an award from the Air Force Summer Fellowship Program and author D P Singh acknowledge the financial support from the CONICYT CHILE (FONDECYT REGULAR) Project award no 1120644. The authors also wish to thank Professor Naushad Ali and Dr. Igor Dubenko of the Southern Illinois University Laboratory for their assistance with X-ray measurements.

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Correspondence to D. P. Singh.

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Singh, D.P., Sirota, B., Talpatra, S. et al. Broom-like and flower-like heterostructures of silver molybdate through pH controlled self assembly. J Nanopart Res 14, 781 (2012). https://doi.org/10.1007/s11051-012-0781-0

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Keywords

  • Silver molybdate
  • Broom-like
  • Flower-like
  • Hydrothermal method
  • Microrods
  • Synthesis method