Bimetallic Cluster-derived Catalysts Research Articles

Mixed-bimetal ruthenium carbonyl clusters supported on silica: Activity and selectivity in CO + H 2 conversion

The catalytic performance of bimetallic Ru-M (M = Co,Fe, Ni, Mo, Rh, Cr, Mn) catalysts prepared from a series of RuM carbonyl clusters in CO hydrogenation has been investigated. The catalysts derived from Ru-Co, Ru-Fe and Ru-Mo bimetallic carbonyl clusters showed high activity and selectivity for higher oxygenates, compared with the Ru6/ SiO2 catalyst prepared from impregnation of monometallic cluster Ru6C(CO)17. For Ru-Ni and Ru-Rh catalysts, they did not show high promotion for the formation of oxygenates although the selectivity was over 10% at 519 K. The promoters such as Mn and Cr in Ru-Mn and Ru-Cr catalysts intensively led to a decrease of oxygenate amount, in comparison with to Ru6/SiO2catalyst. In situ FT-IR studies revealed that the intensity of band at 1584 cm-1 for Ru-M (M=Co,Fe and Mo) bimetallic cluster-derived catalysts at 453 K under syngas (CO/H2= 0. 5) has a good linear relationship to rates of oxygenate formation, whereas the band at 1584 cm-1 was not observed for Ru-Mn, Ru-Cr, Ru-Rh and Ru-Ni bimetallic and monometallic cluster- derived catalysts showing poor activity for oxygenates. This strongly suggested that the band at 1584 cm-1 is likely related to an intermediate to produce oxygenates in CO hydrogenation. Isotopic adsorption of 13CO and D2as well as chemical trapping of surface intermediate suggested that the band at 1584 cm-1 corresponds to fornyl species.

Characterization of HDS/HDN active sites in cluster-derived and conventionally-prepared sulfide catalysts

The catalytic and sorptive properties of a series of sulfide cluster-derived catalysts were compared to those of an analogous series of conventionally-prepared sulfides. The cluster-derived and conventionally-prepared catalysts had similar hydrotreatment activities and chemisorbed similar amounts of O 2 and NO. From infrared spectroscopy, it was observed that the clusters retained much of their character upon adsorption, and that the CO ligands were lost upon heating up to 350 K. Nitric oxide chemisorbed onto the bimetallic cluster-derived catalysts was initially associated with the Co sites then shifted to the Mo sites upon heating, indicating that the promoter and Mo were in close proximity. For the conventionally-prepared materials, NO adsorption suggested that the promoted and unpromoted sites behaved independently. Nitric oxide was more strongly held to the unpromoted sites in both the cluster-derived and conventionally-prepared materials. Thiophene adsorbed onto the cluster-derived and conventionally-prepared catalysts gave rise to nearly identical infrared spectra. Upon heating, the thiophene peaks disappeared and were replaced by peaks that we have attributed to a linear olefin, which is noteworthy since 1-butene was the primary product from thiophene HDS. Nitric oxide easily displaced adsorbed thiophene from the cluster-derived materials, indicating that NO and thiophene adsorbed onto the same sites.

Catalytic Performance in CO Hydrogenation Over SiO 2 -Supported Ru-M (M=Co, Fe,Mo,Ni,Rh,Mn and Cr) Bimetallic Cluster-derived Catalysts

The bimetallic Ru-M (M=Co,Fe,Ni,Mo, Rh,Cr, Mn) catalysts were prepared from SiO 2 -supported bimetallic carbonyl clusters, and it was found that the Ru-Co, Ru-Fe and Ru-Mo bimetallic carbonyl cluster-derived catalysts showed higher activity and selectivity for oxygenates such as C 1 -C 5 alcohols in CO hydrogenation,in contrast to catalysts prepared from SiO 2 -supported homometallic Ru and Co carbonyl clusters. In situ FT-IR studies revealed that the bands at 1584 and 1555 cm -1 species were intermediates to produce methanol and higher oxygenates,and at higher temperatures the 1584 cm -1 species could react with alkyl to form 1555 cm -1 species. By the surface chemical reaction and the IR study of isotopic molecules,it was suggested that 1584 and 1555 cm -1 were assigned to surface formyl and acetyl species.

SiO 2-supported bimetallic ruthenium cluster-derived catalysts for selectivity and activity control in CO hydrogenation toward C 1[sbnd]C 5 alcohols

The bimetallic RuCo 3, RuCo 2 and Ru 3M x C (M = Co, Fe, Ni, Mo, Rh, Cr, Mn, x=1–3) catalysts were prepared from SiO 2-supported carbonyl clusters, and it was found that the RuCo, RuFe and RuMo bimetallic carbonyl cluster-derived catalysts showed higher activity and selectivity for oxygenates such as C 1 C 5 alcohols in CO hydrogenation. In contrast, hydrocarbons and CO 2 were preferentially obtained on the catalysts prepared from SiO 2-supported homometallic Ru 6C, Ru 3 and Co 4 carbonyl clusters. The RuNi, RuCr, RuMn and RuRh carbonyl cluster-derived catalysts provided poor activity and selectivity for oxygenates. The promotion toward alcohol formation on RuCo, RuFe and RuMo cluster-derived catalysts was proposed to be associated with the adjacent Ru-M δ+ (M = Co, Fe, and Mo) at the cluster—oxide support interface to offer C- and O-ended CO ( v(CO) = 1680 cm −1). In situ FT—IR studies revealed that the band at 1584 cm −1, possibly assigned to a formyl intermediate on RuM (M = Co, Fe, and Mo) bimetallic cluster-derived catalysts at 453 K under syngas (CO/H 2=0.5), has a good linear relationship with the rate of oxygenate formation, whereas the 1584 cm −1 band was not observed on RuMn, RuCr, RuRh and RuNi bimetallic and homometallic cluster-derived catalysts showing poor activity for oxygenates. At higher temperatures the higher alcohols (C 2 C 5) are produced via CO dissociation and acetyl intermediate ( v(CO) = 1555 cm 1¯) formation from CO+H 2 on the RuCo cluster-derived catalysts.

ChemInform Abstract: Selective Formation of Lower Alkenes and Alcohols in CO + H2 Reaction Catalyzed on NaY Zeolite‐Encapsulated Rh6 and RhFe Bimetallic Cluster‐Derived Catalysts.

ChemInformVolume 19, Issue 37 Preparative Organic Chemistry ChemInform Abstract: Selective Formation of Lower Alkenes and Alcohols in CO + H2 Reaction Catalyzed on NaY Zeolite-Encapsulated Rh6 and RhFe Bimetallic Cluster-Derived Catalysts. L.-F. RAO, L.-F. RAO Res. Inst. Catal., Hokkaido Univ., Sapporo 060, JapanSearch for more papers by this authorA. FUKUOKA, A. FUKUOKA Res. Inst. Catal., Hokkaido Univ., Sapporo 060, JapanSearch for more papers by this authorM. ICHIKAWA, M. ICHIKAWA Res. Inst. Catal., Hokkaido Univ., Sapporo 060, JapanSearch for more papers by this author L.-F. RAO, L.-F. RAO Res. Inst. Catal., Hokkaido Univ., Sapporo 060, JapanSearch for more papers by this authorA. FUKUOKA, A. FUKUOKA Res. Inst. Catal., Hokkaido Univ., Sapporo 060, JapanSearch for more papers by this authorM. ICHIKAWA, M. ICHIKAWA Res. Inst. Catal., Hokkaido Univ., Sapporo 060, JapanSearch for more papers by this author First published: September 13, 1988 https://doi.org/10.1002/chin.198837088AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume19, Issue37September 13, 1988 RelatedInformation

Selective hydrogenation of CO into C1 and C2 alcohols by SiO2-supported RhFe, PtFe, and PdFe bimetallic cluster-derived catalysts

The cluster-derived bimetallic catalysts prepared from SiO2-supported Rh4Fe, Rh4Fe2, Pt3Fe3, PtFe4, Pd6Fe6, and PdFe4 carbonyl clusters exhibit high catalytic activities and selectivities for formation of oxygenates, consisting mainly of methanol and ethanol, from CO + H2.

Selective formation of lower alkenes and alcohols in CO + H2 reaction catalysed on NaY zeolite-encapsulated Rh6 and RhFe bimetallic cluster-derived catalysts

NaY zeolite encapsulated Rh6 clusters characterized by EXAFS and Fourier transform i.r. spectroscopy led to the selective formation of C2–C4 alkenes in the reaction of CO + H2 under atmospheric pressure, whereas RhFe carbonyl clusters synthesized in NaY showed a unique activity for formation of a mixture of ethanol and methanol.