Synthesis of La2Mo2O9 powders with nanodomains using polyol procedure

Abstract

Powders of oxide-ion conductor La 2 Mo 2 O 9 presenting nanodomains were synthesized by using polyol processes. The influence of different process parameters on the structure and particles morphology was determined. By the classical polyol process, whatever the polyol solvent used (ethylene glycol, diethylene glycol, 1,2-propanediol and tetraethylene glycol) platelet particles with dimensions of few hundred nanometers long and around twenty nanometers thick were observed, as agglomerates of small subparticles. Only with diethylene glycol, pure La 2 Mo 2 O 9 was obtained, whereas with microwave assistance, ethylene glycol also leads to pure product. For both ethylene and diethylene glycol solvent, the microwave assisted process resulted in either agglomerates or desert roses conglomerates after heat treatment at 500°C for 5 min or 2h, respectively. Specific surface areas, ranging between 23 and 36 m².g-1 , have been measured for pure La 2 Mo 2 O 9 powders.

Synthesis by the polyol process and ionic conductivity of nanostructured La2Mo2O9 powders

“…The aim of such a rapid heat treatment was to avoid an important grain growth. It's worth noting that a slightly higher temperature (600°C instead of 550°C) was used for this work, compared to that in our previous publication [10], in order to facilitate the observation of an eventual impurity.…”

“…Nanocrystalline powders allow a good densification (when non aggregated), lower sintering temperatures, better mechanical properties of the electrolytes, and generally improve the electrical properties [9]. Recently, we successfully synthesized nanocrystalline La 2 Mo 2 O 9 powders by the polyol process [10], that presents the advantage of inducing various microstructures [11][12][13] and lowering the temperature of the heat treatment (generally necessary as a final step when soft chemistry is used, in order to reduce the size of the particles obtained [14]).…”

Ageing-assisted room temperature synthesis of La2Mo2O9 powders

“…The tiny band at~1635 cm À1 is probably related to the adsorbed water. According to H. Sellemi and R.A. Rocha's reports, the main absorption bands detected under 1000 cm À1 should be corresponded to inorganic groups (metal-oxygen bonds) [10,16].…”

Investigation of Polyol Process for the Synthesis of Highly Pure BiFeO3 Ovoid-Like Shape Nanostructured Powders

“…. ) due to its reducing capacity, and then it was enlarged for the synthesis of oxides [20] and perovskites [21] displaying improved physical properties, and most of the time totally new emerging electrical and optical features as a consequence of the changed shape, color, and particle size and structure [22] and the enlarged specific area [23,24]. It is interesting to recognize the large range of the possible sizes, going from the mesoscale down to 4 nm [25], which can be useful if one needs to investigate the overturning of physico-chemical properties of some phases based on the particles size.…”