R. Rojas, J. L. M. Vidales, A. Delgado
Oct 1, 1993
Citations
0
Influential Citations
12
Citations
Journal
IEEE Journal of Solid-state Circuits
Abstract
A comparative study of basic and stoichiometric lithium phosphates has been carried out by thermal analysis, X-ray powder diffraction, and IR spectroscopy. Structural and microstructural characterization, carried out by the Rietveld method and a profile-fitting procedure for analysis of broadened X-ray diffraction peaks, reveal that, unlike stoichiometric material, basic lithium phosphate shows a very isotropic and homogeneous crystallite size distribution (mean size 225 [angstrom]). They are justified in terms of the synthesis procedure followed in the preparation of both phosphates. [beta] [r arrow] [gamma]-Li[sub 3]PO[sub 4] transition in the catalyst is shifted up to 670[degrees]C and takes place as an exothermic reaction associated with a dramatic diminution of the surface area (45 to 2 m[sup 2]g). The high surface area and the presence of solvated excess lithium cations, both being a consequence of the synthesis procedure, accounts for the catalytic activity shown by the nonstoichiometric lithium phosphate.