Details

Autor(en) / Beteiligte

• Tirsoaga, Alina
• Visinescu, Diana
• Jurca, Bogdan
• Ianculescu, Adelina
• Carp, Oana

Titel

Eco-friendly combustion-based synthesis of metal aluminates MAl2O4 (M = Ni, Co)

Ist Teil von

• Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology, 2011-12, Vol.13 (12), p.6397-6408

Ort / Verlag

Dordrecht: Springer Netherlands

Erscheinungsjahr

2011

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Nanosized metal aluminates, MAl 2 O 4 (M = Ni, Co), have been prepared following a nonpolluting, low temperature, and self-sustaining starch single-fuel combustion synthesis. The mixed fuel-coordinating actions of starch have given rise to an intermediary precursor which afforded monodisperse metal aluminate nanoparticles. The thermal analysis of the [M(II), Al(III)]-starch precursors indicates a similar thermochemical reactivity for the two compounds, displaying a sequence of well-defined decomposition stages associated with three endothermic effects and three/four (nickel/cobalt) exothermic ones. The XRD data confirm the formation of spinelic phase and a continuous growth of particle sizes with the increase of calcination temperatures. The mechanisms proposed for the formation of metal aluminates essentially consist in a combination of solid-state reactions of amorphous NiO/Co 3 O 4 and Al 2 O 3 simple oxides. The evaluation criterion of Ni(II) cations into the spinelic lattice is original and is based on the distinct occupancy degree of tetrahedral and octahedral sites in NiAl 2 O 4 and γ-Al 2 O 3 . TEM/HRTEM investigations performed on the cobalt(II) and nickel(II) aluminate oxide powders resulted after calcination at 800 and 900 °C, respectively, for 1 h show the formation of irregular and isolated plate-like particles for Co(II)-based spinelic oxides (the average particle size is 16.6 nm) and submicron aggregates of small, bimodal, and almost uniform (as shape and size) of NiAl 2 O 4 mixed oxide (the mean particle size is 33.6 nm). The NIR–UV–Vis spectra for the resulted MAl 2 O 4 (M = Co, Ni) mixed oxides reveal a massive presence of tetrahedral divalent cations both for short- and long-time calcined samples. NiO impurities are detected using FTIR and electronic spectra for all NiAl 2 O 4 samples.