Synthesis and Characterization of Doughnuts Like Cd(OH)_2 Microstructure

Doughnuts like Cd(OH)_2 microstructures were synthesized by aqueous-phase method using carboxyl functionalized polyacrylamide(PAM-COOH)as crystal growth modifiers,which were charac- terized by X-ray powder diffraction(XRD),scanning electron microscope(SEM),transmission electron microscope(TEM)and the selected area electron diffraction(SAED).The influence of experimental conditions such as concentration of surfactant and reactants,temperature and reaction time on the structure and morphology of as-products were carried out in detail.Furthermore,possible formation mechanism of Cd(OH)_2 doughnuts in the presence of PAM-COOH was discussed.Results show that the obtained Cd(OH)_2 doughnuts with size of 1μm is composed of many single-crystal thin flakes with size of about 35nm.The temperature and concentration of reactants have effect on the morphology and size of the obtained product,but PAM-COOH plays a key role in the formation of Cd(OH)_2 doughnuts. Cubic phase CdO with doughnuts structure can be obtained by calcination of Cd(OH)_2 doughnuts at 350℃for 3h.