Physicochemical properties of manganese-containing oxides with a spinel structure prepared with the use of ammonium nitrate and their catalytic activity in carbon monoxide oxidation

Oxide catalysts with the spinel structure with the molar ratios between components Co/Mn = 1: 2, Cu/Mn = 1: 2, and Cu/Co/Mn = 2: 2: 3 (samples I–III, respectively) have been prepared by the decomposition of metal nitrate hydrate solutions in an ammonium nitrate melt. Sample IV with the ratio Cu/Co/Mn = 2: 2: 3 containing 80% γ-Al2O3 is obtained by the addition of γ-Al2O3 powder to the initial melt. The catalysts are characterized using X-ray diffraction analysis, electron microscopy, and local X-ray analysis. Catalytic activity in the reaction of CO oxidation increased in the order I < II < III < IV. The proposed method is simple, and the synthesis is rapid. Oxides with the spinel structure homogeneous in composition and morphology without any impurities can be prepared by this method. These oxides exhibited high catalytic activity in the reaction of carbon monoxide oxidation.