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Synthesis of Vanadium Oxide Gels from Peroxovanadic Acid Solutions: A 51V NMR Study

1999; Elsevier BV; Volume: 148; Issue: 1 Linguagem: Inglês

10.1006/jssc.1999.8283

1095-726X

Bruno Alonso, Jacques Livage,

Transition Metal Oxide Nanomaterials

Vanadium pentoxide gels are formed via the reaction of V2O5 powder with hydrogen peroxide. 51V NMR studies of the solution show that the dissolution of the oxide leads to the formation of solute diperoxo [VO(O2)2]− species. These peroxo species are not stable in the solution. They progressively decompose giving monoperoxo [VO(O2)]+ and then vanadate species. Oxygen gas evolves and a solution of decavanadic acid [HnV10O28](6−n) is formed after few hours. The decavanadic acid then spontaneously dissociates giving rise to the polymerization of V2O5.nH2O gels similar to those currently synthesized via the acidification of vanadate aqueous solutions. These gels exhibit a liquid crystal behavior and give rise to strongly oriented vanadium oxide coatings when deposited onto a flat substrate.