NH4V3O7: Synthesis, morphology, and optical properties

Resumo

The effect of the method used for the synthesis of NH₄V₃O₇ on its morphology, textural parameters, and optical properties was studied. Ammonium vanadate NH₄V₃O₇ was prepared by treating NH₄VO₃ in the presence of citric acid under hydrothermal (4.0 ≤ pH ≤ 5.5, T = 180–200°C, 48 h) and microwave–hydrothermal (3.5 ≤ pH ≤ 5.0, T = 180–220°C, 20 min) conditions. Self-assembled NH₄V₃O₇ microcrystals crystallizing in monoclinic system with unit cell parameters a = 12.247(5) Å, b = 3.4233(1) Å, c = 13.899(4) Å, β = 89.72(3)°, and V = 582.3(4) ų (space group P2₁) were shown to be formed independently of the method used to treat the reaction mixture. The morphology of NH₄V₃O₇ particles was shown to depend on рН of the reaction mass and the method of synthesis. The structural features of NH₄V₃O₇ were studied by IR, UV, and Vis spectroscopy, and the optical bandgap was determined.