Thermal, Structural and Morphological Characterisation of Freeze-dried Copper(II) Acetate Monohydrate and its Solid Decomposition Products

• Autor(a) principal: Bellini,J.V.
• Data de Publicação: 2002
• Outros Autores: Machado,R., Morelli,M.R., Kiminami,R.H.G.A.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Materials research (São Carlos. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392002000400010
• topic: freeze-drying; copper(II) acetate monohydrate; thermal decomposition; Cu oxides; high-temperature X-ray diffractometry

In the present study the thermal decomposition of a freeze-dried copper(II) acetate monohydrate powder, (CH3COO)2Cu.H2O, (FDCuAcH2O), was analysed by a combination of high-temperature X-ray diffractometry; differential scanning calorimetry and thermogravimetry, up to 700 °C. The structure and morphology of the calcined freeze-dried powders were analysed by scanning electron microscopy and X-ray diffractometry. The results showed that FDAcCuH2O decomposes during heating in two stages: I) (25-225 °C) FDCuAcH2O dehydrates giving rise to copper(II) acetate, (CH3COO)2Cu, (AcCu), and II) (225-525 °C) AcCu decomposes to CuO through complex oxidation reactions of Cu and Cu2O, simultaneously. SEM showed that FDCuAcH2O powder has a scale-like morphology, which is created in the freezing stage and retained after freeze-drying. After calcination at 125 and 225 °C, clusters of elongated tubes (or filaments) compose the resulting powder (AcCu). Subsequent calcination at temperatures above 325 °C resulted in hard clusters of spheroid-like CuO particles.