Oxidizing synthesis of Ni2+-Mn3+ layered double hydroxide with good crystallinity

Ni2+-Mn3+ layered double hydroxide (LDHs) with good crystallinity and uniform morphology has been hydrothermally synthesized at 180 degrees C for 2 days using urea as hydrolysis agent and ammonium peroxodisulfate as oxidant. The obtained Ni2+-Mn3+ LDHs material has been characterized by XRD, SEM, XPS, FT-IR, and TG-DTA. Ammonium peroxodisulfate as oxidant plays an important role for the formation of Ni2+-Mn3+ CO32- LDHs material, and Mn2+ ions are oxidized into Mn3+ ones during the precipitation of Mn2+ ions, giving rise to layered hydroxide with the hydrotalcite structure. Ni2+-Mn3+ LDHs material with Ni/Mn molar ratio of 4 has a layered structure with a basal spacing of 0.739 nm. The morphology, size, and uniformity of the as-prepared materials connect with the hydrothermal treatment temperatures, and uniform and regular flowerlike spheres with a mean lateral size of 3.5 mu m are observed for Ni2+-Mn3+ LDHs material with good crystallinity and uniform morphology. (C) 2011 Elsevier Ltd. All rights reserved.