Meso-structured polycrystalline MCo2O4(4.5) (M = Mn, Ni, Fe, Cu) spinels have been successfully fabricated through one-pot pyrolytic method using homogeneous complex oxalates as precursors. In such a protocol, the pyrolysis products, nano-sized spinel crystallites, connected together to form mesoporous structure. Compared with that through nano-casting method, this strategy is much facial and efficient, and resulting material MnCo2O4.5 calcined at 250 degrees C possesses much higher specific area, excellent catalytic activity and stability for CO oxidation at ambient temperature. The full CO conversion can be achieved at as low as 30 degrees C. (C) 2014 Elsevier B.V. All rights reserved.