Preparation of Molybdic Acid Aggregates and Molybdenum Trioxide Powder with Controllable Size and Morphology

Abstract

Molybdic acid aggregates were prepared by the reaction of ammonium molybdate with HNO_3 and HCl in a coexisting HAc or cetyl-trimethyl ammonium bromide (CTAB) solution,respec- tively.The results indicate that the size and morphology of as-prepared molybdic acid aggregates and annealed produets-α-MoO_3 powder were affected by the concentration of ammonium molybdate,HAc and CTAB.The molybdic acid aggregates with diameter of 1-2μm and length of several decades-micron can be obtained by the reaction of higher-concentration ammonium molybdate with HNO_3 in a coex- isting HAc or CTAB solution,repectively.After the as-prepared molybdic acid aggregates are annealed at 500-600℃for 3h,the nanometer-scaled lamellate and sub-micrometer MoO_3 powder are prepared. In addition,irregular molybdic acid aggregates rods are achieved by the reaction of lower-concentration ammonium molybdate with HCl in a coexisting CTAB solution.