2007 Volume 50 Issue 1 Pages 16-22
Catalytic features of supported and unsupported ruthenium containing polyoxomolybdate anion (Ru2Mo14) were evaluated using the methanol transformation reaction. Decomposition of methanol into hydrogen (H2) and carbon monoxide (CO) predominantly occurred over unsupported Ru2Mo14 whereas no acid-catalyzed reaction (formation of dimethyl ether, DME) occurred indicating that Ru2Mo14 had a weak acidity or had no acidity. Ru2Mo14 was homogeneously loaded up to ca. 40 wt% on silica and titania that had been chemically modified with N -(2-aminoethyl-3-aminopropyltrimethoxysilane. Ru2Mo14 catalysts supported on these modified supports exhibited higher conversion of methanol than Ru2Mo14 catalysts either unsupported or supported on unmodified supports, indicating that Ru2Mo14 was highly dispersed on the modified supports. Even in the presence of water vapor, no steam reforming of methanol or shift reaction of CO occurred over the supported Ru2Mo14 catalysts. Ru2Mo14 catalyst supported on modified alumina support converted methanol to DME by acid-catalyzed reaction together with the decomposition products, CO and H2, indicating that the Ru2Mo14 catalyst supported on modified alumina possessed strong acidity. FT-IR measurement of the methanol species adsorbed on Ru2Mo14 catalyst supported on modified alumina and the contact time dependency of this reaction suggested that methanol decomposition proceeded via formation of formaldehyde and subsequent decomposition into CO and H2.