Controllable synthesis of triangle taper-like cobalt hydroxide and cobalt oxide

Abstract

Triangle taper-like β-Co(OH)₂ and mesoporous Co₃O₄ microcrystals are synthesized by a simple solid-state crystal reconstruction approach. Ostwald ripening and successive dissolve-reconstruction processes were used to explain the formation mechanism. The electrochemical properties of the β-Co(OH)₂ and mesoporous Co₃O₄ electrodes were investigated by cyclic voltammetry measurements. The specific capacitances are 137.6, 124.8, 108.8 and 98.0 F g⁻¹ at scan rates of 5, 10, 20 and 50 mV s⁻¹ for β-Co(OH)₂; 91.5, 97.4, 90.7 and 70.9 F g⁻¹ for Co₃O₄ sample at scan rates of 5, 10, 20 and 50 mV s⁻¹. The magnetic properties also have been investigated at room temperature.