Polarized Raman spectra of molten carbonates influenced by the surface acidity of the coexisting inorganic powder

Abstract

Raman spectra and the polarization behaviors of molten alkall carbonates coexisting inorganic powder were measured. The deformation and the change of polarization properties by the coexisting with the solid phase are discussed. The symmetry of the band shape of the Raman spectra for CO32- stretching band (vi) was deformed asymmetricaily by coexisting with α-Al2O3 powder. The deconvolution of spectra of mixtures exhibited two band components. The observed bands are evidence of the existence of two different types of CO32- ions in these systems. Raman depolarization ratio for molten carbonate systems increases from the base line with the decrease of the apparent average thickness. The degree of the anomalous behavior of the molten carbonate by the solid phase have been observed in the order of α-Al2O3 > γLiAOl2 > ZrO2 which is related to the surface acidity defined by the value of point of zero charge (pzc). Consequently, the carbonate ion is deformed asymmetrically by coexisting with inorganic oxide powder.