Driven by global urbanization, people spend up to 90% of their daily lives within enclosed spaces, where pollutant concentrations are 5 to 10 times higher than outdoors, making indoor air degradation a critical environmental and public health challenge. This thesis addresses this issue by developing cost-effective, active, selective and stable catalysts with reproducible performance at low-to-medium temperatures, using carbon monoxide (CO) and ethylene (C2H4, a VOC) as probe target molecules. Manganese oxides were selected as the catalytic matrix due to low cost and high availability. Two distinct ambient-temperature synthesis pathways—redox and carbonate precipitation—were evaluated using different precursors. All synthesized samples underwent comprehensive physicochemical characterization (N2-physisorption at -196 °C, H2-TPR, XPS, XRD) to establish structure-property-performance correlations.