Co–Mn-oxide spinel catalysts for CO and propane oxidation at mild temperature

• Controlled decomposition of mixed oxalates.
• Environmentally friendly, easy and low cost synthesis process.
• Large surface area CoxMn3−xO4 (0 ≤ x ≤ 3) spinel oxides.
• Outstanding catalytic activity propane oxidation at mild temperature.
• Active for CO oxidation at ambient temperature.

CoxMn3−xO4 oxides (0 ≤ x ≤ 3) were prepared by controlled decomposition of mixed oxalates near 200 °C, followed by a calcination at 300 °C. These oxides are amorphous for x < 0.9. For higher cobalt fraction they have a cubic spinel structure and their crystallite size grows with the cobalt fraction. These materials have a large surface area; the highest values, exceeding 250 m2/g, were obtained for x ≈ 2. The spinel oxides exhibit an outstanding catalytic activity for propane oxidation at mild temperature (20–200 °C). They are also active for CO oxidation at ambient temperature. This high activity was correlated both with the surface area and the cobalt concentration. The most efficient material is Co2,3Mn0,7O4, which has a better activity than cobalt oxide catalysts reported in the literature.

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