Template-Assisted Synthesis of Metal Oxide Hollow Spheres Utilizing Glucose Derived-Carbonaceous Spheres As Sacrificial Templates

Haitham Mohammad Abdelaal and Bernd Harbrecht

A series of metal oxides hollow spheres (Cr2 O3 , α-Fe2 O3 , Co3 O4 , NiO and ZnO) have been fabricated using the glucose derived-carbonaceous spheres as sacrificial templates and the metal chlorides as precursors for the metal oxides in a sacrificial templating process. Heating of an aqueous solution of the metal chloride and glucose in an autoclave at 180 ºC affords - as indicated by transmission electron microscopy (TEM) - a nanospherical composite consisting of a metal precursor shell sheathing a carbonaceous core. Consequently, hollow crystalline oxides spheres are obtained by removal of the carbonaceous cores through calcination in air. Correlations between the particle size and the various synthesis conditions such as glucose concentration, the molar concentration ratio between glucose and metal chloride, temperature, reaction time and the addition of acetic acid as a catalyst are uncovered. The obtained metal oxides hollow spheres were characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray powder diffraction (XRD), infrared spectroscopy (IR), and nitrogen adsorption/desorption isotherms (BET).