Raman study of the formation of beta silicomolybdic acid supported on silica, prepared by impregnation method

Abstract

Beta silicomolibdic acid/silica (β-SMA, a metastable form of silicomolybdic acid - H(4)SiMo(12)O(40)) forms by the impregnation of fumed silica into molybdenum solution obtained by hydrolyzation of MoO(2)Cl(2.) β-SMA/silica is found to be stable up to 300 °C after calcination for 1h due to the existence of an interlayer MoO(3) between silica surface and β-SMA. Structures of molybdenum species in the preparation process (including precursor solution) were analyzed by Raman spectroscopy and XRD.