Synthesis and characterization of mesoporous Fe–Co mixed oxide nanocatalysts for low temperature CO oxidation

• Mesoporous Fe–Co mixed oxide nanocatalyts were prepared by co-precipitation method.
• Fe–Co mixed oxides exhibited remarkable catalytic performance toward CO oxidation.
• The catalytic activity was correlated with the amount of chemisorbed oxygen.
• The addition of Co3O4 into Fe2O3 decreases the activation energy of CO oxidation.
• No obvious deactivation observed with repetition using of Fe–Co nanocatalysts.

The catalytic oxidation of CO into CO2 on mesoporous Fe–Co mixed oxide nanocatalysts at low temperature was carried out. The catalysts with different ratios of Co3O4 (1–30 wt.%) were prepared by a simple co-precipitation method. The original and calcined catalysts were characterized by TG, DTA, XRD, TEM, VSM, N2 sorption analysis, surface chemisorbed oxygen and dc electrical conductivity measurements. The results revealed that the addition of Co3O4 to Fe2O3 monotonically increases the amount of surface chemisorbed oxygen, electrical conductivity and catalytic activity of the nanocatalysts. The role of the active redox sites established in these nanocatalysts such as, Co3+/Co2+, Fe3+/Fe2+ and Co3+/Fe2+ which are responsible for such modification was discussed. The magnetic studies indicated that the Fe–Co mixed oxide nanocatalysts exhibited ferromagnetic nature and the catalyst containing 30 wt.% Co3O4 calcined at 600 °C possessed the highest saturation magnetization (Ms = 51.5 emu g−1). In addition the kinetic data illustrated that, the activation energy values of CO oxidation gradually decreased with increasing of Co3O4 content. Moreover, the catalytic behavior under different atmospheres during calcination was also studied.