Preparation and characterisation of cobalt?copper hydroxysalts and their oxide products of decomposition

Three cobalt-copper hydroxysalts with chemical formulae Co(CO3)0.5(OH)1.0.0.11H2O, Co0.67Cu0.33(CO3)0.4(OH)1.2 and Co0.49Cu0.51(CO3)0.43(OH)1.14 have been obtained and characterised by powder X-ray diffraction (XRD), thermal analysis (TG, DTG and DTA), diffuse reflectance spectroscopy (DRS), magnetic susceptibility and X-ray photoelectron spectroscopy (XPS). The above precursors treated at 723 K for 24 h both in N2 and in air give several cobalt and copper oxides which were characterised by magnetic susceptibility, X-ray diffraction, X-ray photoelectron spectroscopy and diffuse reflectance. Depending on the Co:Cu atomic ratios and on the treatments with various gases, the products consist of oxides such as CoO, CuxCo1-xO, CuCoO2 and CuxCo3-xO4 for the samples calcined in N2, and Co3O4, CuxCo3-xO4 and CuO for those calcined in air.