Study of Surface-Bulk Distribution of Tungsten in WO3/ZrO2 Oxides Prepared by Different Methods

The citrate method for the synthesis of superacid WO3/ZrO2 is pro posed. The data on W surface-bulk distribution in WO3/ZrO2 samples prepared by three methods confirm the formation of solid solution of W6+ ions in zirconia lattice. Difference of WO3/ZrO2 lattice cell parameters calculated from the XRD data compared to pure ZrO2 also verifies formation of the solid solution. Isolated WO4 2 - tetrahedra at tached to surface of Zr4+ ions could form strong acidic sites according to the data on surface W content. The distribution on strength of acid sites for the superacid WO3/ZrO2 in the range of –5.6 greater-than or equal to Ho greater-than or equal to –14.5 was determined.