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

✍ Scribed by Bruno Alonso; Jacques Livage

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 119 KB
• Volume: 148
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8283

✦ Synopsis

Vanadium pentoxide gels are formed via the reaction of V 2 O 5 powder with hydrogen peroxide. 51 V NMR studies of the solution show that the dissolution of the oxide leads to the formation of solute diperoxo [VO(O 2 ) 2 ] ؊ species. These peroxo species are not stable in the solution. They progressively decompose giving monoperoxo [VO(O 2 )] ؉ and then vanadate species. Oxygen gas evolves and a solution of decavanadic acid [H n V 10 O 28 ] (6؊n) is formed after few hours. The decavanadic acid then spontaneously dissociates giving rise to the polymerization of V 2 O 5 .nH 2 O gels similar to those currently synthesized via the acidi5cation of vanadate aqueous solutions. These gels exhibit a liquid crystal behavior and give rise to strongly oriented vanadium oxide coatings when deposited onto a 6at substrate.