Effect of calcination temperature on the porous structure of cobalt oxide micro-flowers

Mesoporous cobalt oxide micro-flowers have been synthesized by a simple, surfactant-free method without employing any templates. In this method, cobalt hydroxide micro-flowers were initially prepared in a solution medium. Subsequently, they were applied as a precursor of cobalt oxide by heat treatment, to transform into porous micro-flowers. The morphology of cobalt oxide retained that of its precursor. Experimental analysis confirmed that calcination temperature had great influence on the pore structure and crystal size. The average size of cobalt oxide crystals increased with increasing calcination temperature. Nitrogen adsorption/desorption data showed that the pore size increased and the BET surface area decreased with the gradual increase of calcination temperature. The electrochemical properties of the cobalt oxide were investigated by cyclic voltammetry measurements.