CO HYDROGENATION TOWARDS HIGHER ALCOHOLS CATALYZED ON SIO2-GRAFTED AND ZEOLITE-ENTRAPPED RU, CO AND RUCO BIMETALLIC CLUSTERS - THEIR EXAFS AND FTIR CHARACTERIZATION AND CATALYTIC PERFORMANCES

Some Ru and Co carbonyl clusters in zeolite pores such as Ru-3(CO)12/N aY, [HRu6(CO)(18)](-)/NaY, [Ru-6(CO)lg](2-)/NaX, Co-4(CO)(12)/NaY and Co-6(CO)(16)/NaY were prepared by the ship-in-bottle technique, and ch aracterized by FTIR and EXAFS. The RuCo bimetallic carbonyl cluster wa s prepared by reductive carbonylation of the oxidized RuCo/NaY, which provides the proposed assignment to [HRuCo3(CO)(12)]/NaY. The tailored Ru, RuCo and Co catalysts were prepared by H-2 reduction from the pre cursors, e.g. Ru, RuCo bimetallic and Co carbonyl clusters impregnated on SiO2 and entrapped in NaY and NaX zeolites. The RuCo bimetallic ca rbonyl cluster-derived catalysts showed substantially higher activitie s and selectivities for oxygenates such as C-1-C-5 alcohols in CO hydr ogenation (CO/H-2 = 0.33-1.0, 5 bar, 519-543 K). By contrast, hydrocar bons such as methane were preferentially obtained on the catalysts pre pared from Ru-6, Ru-3 and Co-4 carbonyl clusters and provided lower CO conversion and poor selectivities for oxygenates. The RuCo bimetals a re proposed to be associated with the selective formation of higher al cohols in CO hydrogenation.