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La0.67Ce0.03Sr0.3MnO3-coupled microwave assisted ultra-fast synthesis of nanocrystalline Cobalt oxide and Bismuth oxide

Abstract:

Bismuth hydroxide and Cobalt hydroxide gels were freshly prepared by adding aqueous sodium hydroxide to their corresponding nitrates under basic conditions. Then they were oven dried at 373 K and found to be amorphous in X-ray diffraction (XRD) study. They crystallized into their respective oxides by microwave irradiation (2.45 GHz) in merely 2 min using La<inf>0.67</inf>Ce<inf>0.03</inf>Sr<inf>0.3</inf>MnO<inf>3</inf> (LCSMO) as couplant in a microwave domestic oven (~ 100 W). This is the lowest temperature treatment and synthesis time so far reported in the literature for the formation of these systems. Formation of nanocrystallites of Bi<inf>2</inf>O<inf>3</inf> (10 nm) and Co<inf>3</inf>O<inf>4</inf> (15 nm) has been confirmed by XRD. Normally these hydroxides produce oxides only on heating at temperature > 673 K or digesting them at 373 K for 4 - 6 hours as reported by us earlier. Microwave assisted heating proves to be a novel technology whose applications can be carefully harnessed due to its unique effects compared to the conventional heating, such as rapid volumetric heating, shortened reaction time and energy saving. © 2007 Elsevier B.V. All rights reserved.