Formation of Copper–Manganese Oxides from CuxMn1−x(HCOO)2·2H2O Mixed Crystals

Chromatographic effect during the preparation of γ-Al2O3 supported Cu−Mn catalysts

“…Obviously, the magnetic moments have close values with the exception of sample $7, but the specific magnetic susceptibilities differ. Such differences could be expected since Cu-Mn formates form no continuous series of mixed crystals [6] as well as the crystallization in the pores proceeds with continuous change of the solution composition resulting in the formation of series of mixed crystals. Probably the chromatographic effect plays some role as also does the fact that the crystallization proceeds in pores with different diameters.…”

“…The magnetic moment values were calculated according to the formula ~t~r = 2.828 ~/z,--~-~. Table 2 also contains theoretically calculated magnetic moments in accordance with [9] as well as the experimentally determined magnetic moments of the mixed CuxMn~=x(HCOO)z.2H20 crystals synthesized by us [6] and having compositions close to those of the supported ones. Obviously, the magnetic moments have close values with the exception of sample $7, but the specific magnetic susceptibilities differ.…”

“…The metal contents in the impregnating solutions (C~p), in the solutions after impregnation (C~d) and in the supported metal formate (Cs~) were determined by chemical analysis [6] (A13 § being masked with NH~y).…”

“…Further, it might be expected that the thermal decomposition of mixed crystals as precursors would lead to the formation of supported mixed oxides with high dispersion and catalytic activity. It has been established that the isostructural Cu and Mn formate dihydrates form mixed crystals during their cocrystallization from aqueous solutions [5,6] and mixed Cu-Mn oxides have been obtained in their thermal decomposition at low temperatures (300~ [6].…”

Surface and Texture Characterization of Alumina-Supported Copper and Mixed Copper–Manganese Oxide Catalysts and Their Formate Precursors

“…The calcination of the parent formate samples at 670 K leads to the separation of water molecules (coordinated or hydrogen bonded) and hydroxyls and to the decomposition of the adsorbed formate ions, thus resulting in the formation of Al-O-Me, Al-O-Al, and Me-O-Me bonds. It is well known that at temperatures below 800 K and low metal loadings the surface "spinel-like" structures are formed in the case of the copper samples (41,42 (19).…”