MnCo2O4 preparation by microwave-assisted route synthesis (MARS) and the effect of carbon admixture

• Catalyst spinel MnCo2O4 with particle size <30 nm was prepared by a novel microwave-assisted route. To determine the optimal amount of carbon needed as a microwave susceptor, varying amounts of amorphous carbon powder (7-26 wt %) were mixed with the aqueous solutions of Mn- and Co-nitrates. After heat treatment at 200degreesC in a conventional oven, the mixtures were heat-treated in a microwave oven (2.45 GHz) at a power of 350 W. The effect of the carbon amount on the formation and properties of the catalysts was studied. In this production method, 13 wt % of carbon was found to be the minimum needed for spinel MnCo2O4 formation. Most of the carbon was oxidized during the microwave treatment. When the carbon content in the nitrate-carbon mixture was increased beyond 13 wt %, the carbon content and the specific surface area of the final catalyst started to decrease. However, the carbon amount of 18 wt % in the initial nitrate-carbon mixture was found to be the most preferable when considering the catalytic activity of the spinel toward oxygen reduction reaction in alkaline electrolyte.

Nyckelord

heterogeneous catalytic reactions

graphite air electrodes

alkaline fuel-cell

oxygen reduction

oxides

co

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