Mixed iron-rhodium carbidocarbonyl clusters on oxide supports: chemistry and catalysis of syn-gas reactions
✍ Scribed by V.I. Kovalchuk; N.M. Mikova; N.V. Chesnokov; L.V. Naimushina; B.N. Kuznetsov
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 676 KB
- Volume
- 107
- Category
- Article
- ISSN
- 1381-1169
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✦ Synopsis
Genesis of silica-supported [FesRhC(CO)t~]-and [Fe4RhC(CO)~4]-clusters with interstitial carbon atoms have been investigated in CO, syn-gas and Ar media. Complete conversion of the former cluster to the latter was obtained at 50°C in any medium, with [Fe4RhC(CO)I4] cluster yielding Fe4Rh2C(CO)I 6 and [Fe3Rh3C(CO)Is] mixtures at 100-150°C. Simultaneously, Fe z + ions emerged on the SiO2 surface. M6ssbauer and electron microscopic studies on the silica-deposited clusters showed that at treatment in any medium in the range of 250-350°C highly dispersed FeRh particles are located on the silica surface, where Fe atoms exist mainly in the oxidized state even after H2 reduction. Silica-supported catalysts derived from a family of FeRh carbidocarbonyl clusters were found to exhibit increased activity and selectivity toward oxygenates in CO hydrogenation and C~H6 hydroformylation compared to those of monometallic cluster-derived catalysts. Possible explanations are discussed.