Investigation of the reactivity of AlCl3 and CoCl2 toward molten alkali-metal nitrates in order to synthesize CoAl2O4

Abstract

Cobalt aluminate CoAl 2 O 4 powder, constituted of nano-sized crystallites, is prepared, involving the reactivity of AlCl 3 and CoCl 2 with molten alkali-metal nitrates. The reaction at 450 °C for 2 h leads to a mixture of spinel oxide Co 3 O 4 and amorphous γ-Al 2 O 3 . It is transformed into the spinel oxide CoAl 2 O 4 by heating at 1000 °C. The powders are mainly characterized by XRD, FTIR, ICP, electron microscopy and diffraction, X-EDS and diffuse reflection. Their properties are compared to those of powders obtained by solid state reactions of a mechanical mixture of chlorides or oxides submitted to the same thermal treatment.

The Preparation of Blue CoAl2O4Powders by the Malonate Method: The Effect of the Amount of Malonic Acid Used, the Formation Pathway of CoAl2O4Crystallites and the Characteristics of the Prepared Powders

“…The FTIR spectra in Figure 6(a) and (b) show the characteristic bands due to normal CoAl2O4 at below 800 cm -1 . 6,8 The absorption band at 666 cm -1 was assigned to the Al-O stretching vibration of the AlO 6 octahedra and the bands at 511 and 556 cm -1 were attributed to the Co-O stretching vibration of the CoO4 tetrahedra. 12 However, the characteristic bands for CoAl2O4 were not observed in the FTIR spectrum of Fig 6(c).…”

“…4 A variety of techniques are used to prepare CoAl 2 O 4 . [5][6][7][8][9] Combustion is one method of producing metal oxide by burning a fuel. The nitrate anion and citric acid of the organic acids are mainly used as the oxidant and a fuel, respectively.…”

Co-doped Attapulgite Catalyzed Solvent-free Oxidation of Cyclohexane Using Molecular Oxygen

“…In comparison with AT, a slight decrease of crystallinity in the Co-AT samples is observed, indicating that Co could enter into the framework of AT or interact with Al and Fe species of AT. Durand et al [13] illuminate the differentiation between the spinel phases Co 3 O 4 and CoAl 2 O 4 . The peak of the spinel phase at 2h = 18.9°, characteristic of Co 3 O 4 [14], is present in the five diffraction diagrams.…”

Glycothermal Synthesis and Catalytic Properties of Nanosized Zn1−x Co x Al2O4 (x = 0, 0.5, 1.0) Spinels in Phenol Methylation

“…solid state reaction (ceramic, mechanochemical) method [8] or wet chemical routs such as (co)precipitation [9], sol-gel [10], solvothermal methods [11] and some other methodologies like molten salts synthesis [12], combustion in various solutions [3], polymeric precursors method [13], etc. Glycothermal method, being one type of the solvothermal process, offers some advantages over most other methods like short reaction time, the possibility of using various precursors and reaction media.…”