Preparation and Catalytic Ability of Novel Manganese Carbonate Ore/Copper and Cobalt Oxide-based Composites for Ozone Decomposition and Discolouration of Malachite Green Dye

Abstract

In the present study the new manganese carbonate ore/copper and cobalt oxide-based catalysts were prepared using co-precipitation followed by calcination at 500^◦C or by hydrothermal synthesis at 160^◦C and then thermal treatment. The phase composition, structure, morphology, specific surface area and textural characteristics of the obtained composites were characterized by several methods as PXRD analysis, FTIR spectroscopy, SEM, nitrogen adsorption-desorption isotherms, and measurement of specific surface area. The PXRD analysis determined the average crystallite size of 10nm for Co₃O₄ and MnCo₂O₄ and 13–23nm for CuO phases. The synthesized composites exhibit mesoporous structure. The highest specific surface area (135m2/g) was established for thermally treated MnCO₃ ore/cobalt oxide in comparison with the other investigated samples. The prepared materials were tested in two reactions – ozone decomposition and photocatalytic discolouration of Malachite Green (MG) dye as model pollutant under UV light. The results reveal that the hydrothermally treated MnCO3 ore/cobalt and copper oxide demonstrate higher catalytic ability about removal of ozone (87% and 63%) in comparison with the composites prepared by co-precipitation and calcination – 86% and 54%, respectively. Best results for discolouration of MG dye were achieved with MnCO3 ore/cobalt oxide-based photocatalyst (76%).