Ceria (CeO₂) and zirconia (ZrO₂) supported Pt and Co₃O₄-based nanocatalysts were synthesized and characterized by different instrumental techniques. The catalysts redox properties and active surface areas were evaluated using temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO) and H₂-pulse chemisorption, respectively. The catalysts were tested for the thermal oxidation of carbon monoxide (CO), reduction of nitrous oxide (N₂O) and conversion of N₂O/CO mixture (1:1 vol%) . In catalytic tests, Pt–Co₃O₄/CeO₂ (10:10%) oxidized CO up to 100% at 25 °C and Co₃O₄/CeO₂ (20%) reduced N₂O up to 90% at 320 °C. Moreover, Pt–Co₃O₄/CeO₂ (10:10%) converted N₂O/CO mixture to N₂/CO₂ up to 90% at about 210 °C. The low-temperature catalytic activity of Pt–Co₃O₄/CeO₂ (10:10%) for CO oxidation and N₂O/CO mixture redox conversion were attributed to uniform particle size, metals and support proper combination and electron interaction.