Preparation of different manganese oxide structures via controlling the concentration and the type of the alkaline media

Birnessite and manganite materials were prepared using a simple precipitation process in an alkaline medium. Potassium hydroxide and tetraethyl ammonium hydroxide (TEAH) used as the precipitating agents. Different techniques such as XRD, DSC, TGA, FTIR, TEM and N2 adsorption analyses were employed to characterize the prepared samples. The results revealed that the formed phase in the prepared sample is dependent on the concentration of the precipitating agent. In addition, the XRD results showed the formation of various phases through controlling the concentration of the precipitating agent. Pure phase of birnessite produced in the high alkaline medium, and manganite (γMnOOH) at relatively low alkalinity. The samples prepared by using TEAH were well crystalline compared with the analogue one prepared by KOH. The obtained results elaborated the role of TEAH in directing the order of the particles during the preparation step.