Manganese carbonate ore/copper and cobalt oxide catalysts were prepared using co-precipitation followed by calcination at 500^oC or hydrothermal synthesis at 160^oC and then thermal treatment. The natural manganese carbonate ore is a suitable support due to its stability and low cost. The phase and chemical composition, structure, morphology, specific surface area, and textural characteristics of the obtained composites were characterized by several methods, such as as powder X-ray analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, electron dispersive spectroscopy, nitrogen adsorption–desorption isotherm, and the BET method. The average crystallite size of 10 nm for Co₃O₄ and 13-23 nm for CuO phases was determined. The prepared 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 catalytic activity of synthesized composites was tested in the ecologically important reaction of ozone decomposition. The higher ozone conversion degree was reached using hydrothermally treated MnCO₃ ore/cobalt oxide (87%) and MnCO₃ ore/copper oxide (63%) in comparison with thermally treated catalysts (86% and 54%), respectively.

Acknowledgments: This work has been carried out in the framework of the National Science Program, "Critical and strategic raw materials for a green transition and sustainable development", approved by the Resolution of the Council of Ministers № 508/18.07.2024 and funded by the Ministry of Education and Science (MES) of Bulgaria. The technical support from the project PERIMED BG05M2OP001-1.002-0005 /29.03.2018 (2018–2023) is acknowledged.