Photocatalytic Activity of Co₃O₄ Synthesized via Sol–Gel Method in the Oxidation of Carbon Monoxide Under Visible Light Irradiation

A Co₃O₄ was obtained using the sol–gel method, and its morphology and spectral characteristics have been examined. The presence of polyhedral Co₃O₄ particles with a size of 200-500 nm has been established by means of XRD and SEM methods. It is shown that the obtained material exhibits two values of band gap (1.4 and 2.35 eV), which can be attributed to the presence of cobalt ions in different oxidation states (Co²⁺ and Co³⁺). The photocatalytic properties of the material were studied in the process of CO oxidation. The carbon monoxide conversion is found to exceed 60 % after 180 min of irradiation. A possible mechanism of the process is discussed.