Manganese oxide (Mn3O4) and metal (Cu, Co and Ni) substituted Mn3O4 catalysts have been synthesised using single step solution combustion method. Catalysts were characterized using XRD, XPS, SEM and TEM and BET. The particle sizes of the catalysts were between 21 and 27 nm. CO oxidation was carried out over these catalysts. Cu substituted Mn3O4 showed the highest activity with full conversion of CO occurring around ∼ 225 °C. DRIFTS was used to investigate the mechanism of CO oxidation. The reaction was modelled using Langmuir − Hinshelwood mechanism and the activation energy was found to be 44.4 kJ mol−1. The high activity of Cu doped Mn3O4 indicates its potential to replace noble metal based catalysts. © 2016 Elsevier B.V.