Voltammetric and X-ray diffraction analysis of the early stages of the thermal crystallization of mixed Cu,Mn oxides

0100763 - UACH-T 20043010 RIV US eng J - Journal Article
Grygar, Tomáš - Rojka, T. - Bezdička, Petr - Večerníková, Eva - Kovanda, F.
Voltammetric and X-ray diffraction analysis of the early stages of the thermal crystallization of mixed Cu,Mn oxides.
[Voltametrická a rtg difrakční analýza raných stadií tepelné krystalizace smíšených oxidů Cu a Mn.]
Journal of Solid State Electrochemistry. Roč. 8, č. 4 (2004), s. 252-259. ISSN 1432-8488. E-ISSN 1433-0768
R&D Projects: GA MŠMT LN00A028
Institutional research plan: CEZ:AV0Z4032918
Keywords : amorphous phases * Cu,Mn oxides * hydrotalcite
Subject RIV: CA - Inorganic Chemistry
Impact factor: 0.984, year: 2004

Mixed Cu,Mn, Cu,Mn,Al, Cu,Mg,Mn, and Cu,Mg,Mn,Al oxides were obtained by calcination of amorphous basic carbonate (Cu,Mn oxides) or hydrotalcite-like precursors at 300-800 degreesC. The product composition was characterized by chemical analysis, XRD, and voltammetry of the microparticles. The XRD amorphous portion was detected indirectly by XRD and directly by voltammetry. Tenorite (CuO) and spinels were the main crystalline components of the oxide mixtures. The presence of Al shifted the onset of the crystallization of XRD-detectable tenorite and spinel to temperatures higher by 100-200 degreesC, and the presence of Mg shifted tenorite crystallization by 100 degreesC, but voltammetry was able to detect these phases even in XRD-amorphous or nanocrystalline calcines. Voltammetry is hence suitable for analysis of poorly crystalline oxides that can be used in heterogeneous catalysis.

Smíšené oxidy Cu-Mn a Cu-Mn s Mg případně Al byly připraveny žíháním amorfních sloučenin nebo sloučenin se strukturou hydrotalcitu. Byla sledována teplotní závislost ubývání amorfních meziproduktů a tvorby CuO a spinelových oxidů.
Permanent Link: http://hdl.handle.net/11104/0008253