Multi-component fitting XAFS analysis of molybdate species during catalystpreparation by the molten salt method

The goal of the present study was to elucidate the formation mechanisms of highly dispersed catalysts by the molten salt method. For this purpose, mul ti-component fitting Mo K-edge EXAFS analysis was applied to the structure of molybdate catalysts prepared in KNO3 and NaNO3. The analysis revealed th at MoO3 dissolved in molten salts was at first transformed into polymolybda te anions and finally into MoO42- anions. The transformation into MoO42- an ions took place at a lower temperature when NaNO3 was used as molten salt t han KNO3. In contrast, polymolybdate anions were stable even at higher temp erature when ZrO2 was added as a support of molybdate.