Formation of Active Structures in Monolith Copper–Manganese Oxide Catalysts for Air-Heating Devices

Resumo

Impregnation catalysts based on CuO, MnO_x, and CuO–MnO_x with different Cu/Mn ratios supported on ceramic monoliths of alumina and silica are studied by BET, mercury porosimetry, X-ray diffraction analysis, transmission and scanning electron microscopy, temperature-programmed reduction with H₂, diffuse reflectance electron spectroscopy, and differential dissolution. It is found that, in the butane oxidation reaction, CuO–MnO_x catalysts exert a synergistic effect, which is attributed to the formation of highly defective phases of complex oxides of the nonstoichiometric spinel type with a large number of interparticle boundaries in the near-surface layers of the support.