Morphology controlled NH4V3O8 microcrystals by hydrothermal synthesis

Abstract

Single crystalline ammonium trivanadate NH₄V₃O₈ with variable morphologies, including shuttles, flowers, belts, and plates, was synthesized by the hydrothermal treatment of NH₄VO₃ with acetic acid. The crystals optimally grow under gentle conditions of 140 °C for 48 h. The resulting NH₄V₃O₈ microcrystals were characterized by means of X-ray diffraction, scanning electron microscopy, infrared and Raman spectroscopy, static magnetization studies, and thermal analysis. The key factors to control the size and morphology of the crystals are the pH value and the vanadium concentration. A tentative microscopic growth mechanism is proposed and it is demonstrated how shape and morphology of the resulting microcrystalline material can be tuned by appropriate synthesis parameters.