Encyclopedia of Membranes

2016 Edition
| Editors: Enrico Drioli, Lidietta Giorno

Free Protons in Solid Heteropoly Compounds

Reference work entry
DOI: https://doi.org/10.1007/978-3-662-44324-8_1734
The basic structure of hetropoly acid hydrates (HPAs∙nH 2O) has already been determined by Keggin ( 1934), but the water and hydrated proton entities filing the channels (secondary structure) have not been studied much until the early 1990s. As heteropoly acids are superionic proton conductors at room temperature and good catalysts, it is clear that their activities will be the function of hydration degree and dynamics of proton species. Therefore, it was necessary to focus on the studies that identify protonic entities and follow their dynamics. The studies started on WPA-6, the most stable hydrate of WPA with well-known structure. Crystallographic results for WPA-6 show that Keggin’s anions in WPA-6 are stabilized by dioxonium ion H 5O 2 +, which was defined as planar and rigid (Brown et al. 1970). On the other hand, IR and Raman spectra taken at room temperature have shown that different protonic species (H 5O 2 +, H 3O +, H 2O) exist in dynamic equilibrium (Mioč et al. 1991, 2005; Colomban...
This is a preview of subscription content, log in to check access

References

  1. Brown GN, Noe-Spirlet MR, Busing WR, Levy HA (1970) Dodecatungstophosphoric acid hexahydrate, (H5O2+)3(PW12O403–). The true structure of Keggin’s ‘pentahydrate’ from single–crystal x–ray and neutron diffraction data. Acta Cristalogr B33:1038–1045Google Scholar
  2. Chatzidimitriou-Dreismann CA, Abdul-Redah T, Streffer RMF, Mayers J (2002) Sub-femtosecond dynamics and dissociation of C-H bonds in solid polystyrene and liquid benzene. J Chem Phys 116:1511–1518CrossRefGoogle Scholar
  3. Colomban P (2013) Proton and protonic species: the hidden face of solid state chemistry. How to measure H-content in materials? Fuel Cells 13:6–18CrossRefGoogle Scholar
  4. Colomban P, Tomkinson J (1997) Novel forms of hydrogen in solids: the ‘ionic’ proton and the “quasi-free” proton. Solid State Ionics 97:123–134CrossRefGoogle Scholar
  5. Essayem N, Tong YY, Jobic H, Vedrine JC (2000) Characterization of protonic sites in H3PW12O40 and Cs1.9H1.1PW12O40: a solid-state1H,2H,31P MAS-NMR and inelastic neutron scattering study on samples prepared under standard reaction conditions. Appl Catal A Gen 194–195:109–122CrossRefGoogle Scholar
  6. Fillaux F, Ouboumour H, Tomkinson J, Yu LT (1991) An inelastic neutron scattering study of the proton dynamics in γ-MnO2. Chem Phys 149:459–469CrossRefGoogle Scholar
  7. Holclajtner-Antunović I, Mioč UB, Todorović M, Jovanović Z, Davidović M, Bajuk-Bogdanović D, Laišević Z (2010) Characterization of potassium salts of 12-tungstophosphoric acid. Mater Res Bull 45:1679–1684CrossRefGoogle Scholar
  8. Janik MJ, Davis RJ, Neurock M (2004) A first principles analysis of the location and affinity of protons in the secondary structure of phosphotungstic acid. J Phys Chem B 108:12292–12300CrossRefGoogle Scholar
  9. Jones DJ, Penfold J, Tomkinson J, Roziere J (1989) Incoherent inelastic neutron scattering studies of proton-conducting materials: Sn(HPO4)2∙H2O and HM(SO4)2∙H2O, M=Fe. In: part II. The vibrational spectrum of H3O+. J Mol Struct 197:113–121CrossRefGoogle Scholar
  10. Kearley GJ, White RP, Forano C, Slade RCT (1990) An analysis of the vibrational frequencies and amplitudes of the H5O2+ion in H4SiW12O40°6H2O (TSA∙6H2O) and H4PW12O40°6H2O (TPA∙6H2O). Spectrochim Acta 46A:419–424CrossRefGoogle Scholar
  11. Keggin JF (1934) Structure and formula of 12-phosphotungstic acid. Proc R Soc A144:75–100CrossRefGoogle Scholar
  12. Kozhevnikov IV (1998) Catalysis by heteropoly acids and multicomponent polyoxometalates in liquid-phase reactions. Chem Rev 98:171–198CrossRefGoogle Scholar
  13. Kremenović A, Spasojević–de Birè A, Bourree F, Colomban P, Davidović M, Mioč UB (2002) Structural modifications of dodecatungstophosphoric acids hexahydrate induced by temperature in the 10–358 K range. In situ high–resolution neutron powder diffraction investigation. Solid State Ionics 150:431–442CrossRefGoogle Scholar
  14. Mioč U, Davidović M, Tjapkin N, Colomban P, Novak A (1991) Equilibrium of the protonic species in hydrates of some heteropolyacids at elevated temperatures. Solid State Ionics 46:103–109CrossRefGoogle Scholar
  15. Mioč UB, Colomban P, Davidović M, Tomkinson J (1994) Inelastic neutron scattering study of protonic species during the thermal dehydration of 12-tungstophosphoric hexahydrate. J Mol Struct 326:99–107CrossRefGoogle Scholar
  16. Mioč UB, Todorović MR, Davidović M, Colomban P, Holclajtner-Antunović I (2005) Heteropoly compounds – from proton conductors to biomedical agents. Solid State Ionics 176:3005–3017CrossRefGoogle Scholar
  17. Mioč UB, Petković M, Davidović M, Perić M, Abdul-Redah T (2008) Proton and protonic entities in solid heteropoly compounds: an ab initio calculation of the environmental effect on the H5O2+ ion. J Mol Struct 885:131–138CrossRefGoogle Scholar
  18. Ratajczak HR, Barnes AJ, Bielanski A, Lutz HD, Müller A, Pope MT (2001) Polyoxometalate Chemistry from Topology via Self-Assembly to Applications. In: Pope MT, Müller A (eds) Kluwer, Dodrecht, pp 100–117Google Scholar
  19. Tjapkin N, Davidović M, Colomban P, Mioč UB (1993) Complex dielectric permittivity, bulk and surface conductivity of 12-tungstophosphoric acid hexahydrate and its dehydrated forms. Solid State Ionics 61:179–185CrossRefGoogle Scholar
  20. Tomkinson J (1992) The vibrations of hydrogen bonds. Spectrochim Acta 48A:329–348CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Faculty of Physical ChemistryUniversity of BelgradeBelgradeRepublic of Serbia