Characterization of solid–solid interactions and physico-chemical properties of copper–cobalt mixed oxides and Cu xCo 3−xO 4 spinels

Abstract

A series of pure and mixed copper and cobalt oxides was prepared by calcination of copper and cobalt nitrate hexahydrate at 500–1000°C. Another series of Cu xCo 3−xO 4 spinel (0.0 ≤ x ≤ 1.0) was synthesized by the decomposition of nitrate precursors at 350°C. The effect of K 2O-doping on the physicochemical properties of the spinel form was investigated. The thermal behavior of the pure and binary solids has been studied using TG, DTG, and DSC analyses. The thermal products were characterized using XRD analysis. The results revealed that, solid–solid interactions take place between anhydrous nitrate precursors and/or oxides to form different forms of copper oxocobaltate. The produced oxocobaltate dissolves the excess of Co 3O 4 forming solid solution of the formula Cu 1−xCo xCo 2O 4. Both copper and cobalt oxides have mutual thermal effects on each other. The catalytic activities of various prepared mixed solids were tested using the catalytic decomposition of H 2O 2 in aqueous solution at 30–50°C.