Influences of surfactants and chelating agent on the formation of manganese oxide nanoparticles through coprecipitation method

Abstract

Manganese oxide nanoparticles were synthesized through coprecipitation method using various surfactants including Tween 20, cetyltrimethylammonium bromide (CTAB), and sodium dodecyl sulfate (SDS). First, the phase I of manganese source with surfactant and the phase II of precipitation agent with surfactant were prepared separately. Manganese nitrate hexahydrate and ammonium hydroxide were used as a manganese salt and a precipitation agent, respectively. Secondly, the phase II was added into the phase I and Mn(OH)2 was formed. Also, ammonium oxalate monohydrate (AOM) was used as a chelating agent to control the activity of manganese cations and the precipitation of Mn(OH)2. Morphology and size of particles were controlled with the variations of concentrations of surfactant and AOM, reaction time, and chelation time. Finally, manganese oxide nanoparticles were obtained by the calcination of Mn(OH)2 at 700 C for 6 hours. The formations of particles were investigated by FE-SEM, HR-TEM, XRD, PSA, and BET.