NH4V3O7: Synthesis, morphology, and optical properties

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) A, b = 3.4233(1) A, c = 13.899(4) A, β = 89.72(3)°, and V = 582.3(4) A3 (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.