Bimetallic cluster-derived heterogeneous catalysts—heteronuclear two-site activation of CO in syngas conversion to oxygenates
TL;DR: In this paper, the authors used SiO2-supported carbonyl clusters as molecular precursors for tailored bimetal catalysts, which exhibited high activity and selectivities for C1 + C2 alcohols in a CO + H2 reaction and higher alcohols for olefin hydroformylation.
About: This article is published in Polyhedron.The article was published on 1988-01-01. It has received 53 citations till now. The article focuses on the topics: Hydroformylation & Migratory insertion.
Citations
More filters
600 citations
TL;DR: In this article, the effect of co-metal on the performance of Pd in bimetallic catalysts is presented, and the main methods to prepare BMo catalysts through the unselective and selective depositions of the cometal precursor and the use of heterobinuclear complexes are highlighted.
Abstract: An overview about the effect of co-metal on the performance of Pd in bimetallic catalysts is presented. In the first part, the promotion of monometallic catalysts by addition of a second metal is described from a general point of view in terms of: (i) electronic effects; (ii) geometric effects; (iii) the occurrence of mixed sites; and (iv) the disappearance of the β-PdH phase. The second part presents the main methods to prepare bimetallic catalysts through the unselective and selective depositions of the co-metal precursor and the use of heterobinuclear complexes. The influence of preparation methods on the chemical state and the spatial distribution of both components are highlighted. In the last part, a short overview is given about the influence of co-metal addition on some important reactions in which Pd is the reference active phase: (i) selective hydrogenation of highly unsaturated aliphatic hydrocarbons; (ii) hydrogenation of aromatics or hydrodearomatisation; (iii) hydrogenation of nitrogen-containing compounds; (iv) reactions involving CO; and (v) hydrodechlorination.
361 citations
TL;DR: In this paper, the robust trigonal prismatic Pt 18 and Pt 15 cluster anions are selectively synthesized via [Pt(CO)Cl 3 ] − in FSM-16 (4.7 nm) and cis -PtCO) 2 Cl 2 in the confined mesoporous channels of FSM16 (2.8 nm) by the FTIR and UV-Vis spectroscopic data.
Abstract: The robust trigonal prismatic Pt 18 and Pt 15 cluster anions are selectively synthesized via [Pt(CO)Cl 3 ] − in FSM-16 (4.7 nm) and cis -Pt(CO) 2 Cl 2 in FSM-16 (2.8 nm) by the reductive carbonylation of H 2 PtCl 6 in the confined mesoporous channels of FSM-16, respectively. The Pt cluster anions extracted from the resulting samples in the THF solution by cation metathesis with [PPN]Cl are identified as [Pt 3 (CO) 6 ] 5 2− in FSM-16 (2.8 nm) and [Pt 3 (CO) 6 ] 6 2− in FSM-16 (4.7 nm) by the FTIR and UV–Vis spectroscopic data. The EXAFS and FTIR studies demonstrated that [Pt 3 (CO) 6 ] 5 2− /FSM-16 (2.8 nm) ( ν CO =2078, 1880 cm −1 ) and [Pt 3 (CO) 6 ] 6 2− /FSM-16 (4.7 nm) ( ν CO =2056, 1879 cm −1 ) were transformed by heating at 300–343 K into the partially decarbonylated Pt clusters (Pt–Pt; C.N.=7.6, R =2.73 A) characteristic of a linear CO band ( ν CO =2015 cm −1 ). According to the EXAFS and TEM observation, Pt carbonyl clusters are eventually converted above 473 K to naked Pt particles of 11 A (Pt–Pt C.N.=6.7, R =2.72 A) in FSM-16 (2.8 nm) and of 15 A (C.N.=7.9, R =2.74 A) in FSM-16 (4.7 nm). On the other hand, the platinum nanowires [2 and 4 nm (diameter)×50–500 nm (long)] are prepared using the cylindrical mesoporous channels of FSM-16 (2.8 and 4.7 nm) in the templating reduction of H 2 PtCl 6 by the exposure to γ-ray or UV-light ( λ max >254 nm) under the atmosphere of 2-propanol and water. It was demonstrated by the TEM observation and EXAFS characterization that the diameters of Pt nanowires formed in FSM-16 are consistent with those of FSM-16 used (2.8 and 4.7 nm), whereas the average lengths of Pt wires are varied by the function of the Pt loading mass and time exposure to γ-ray and UV-light. The observed electron beam diffraction patterns indicate that the Pt wires consist of a single crystal phase of Pt(110) having a lattice fringe of 2.27 A. It is of interest to find that the Pt nanowires in FSM-16 (2.8 nm and 4.7 nm) exhibited an unique IR spectrum in CO chemisorption and the remarkable activities per surface Pt atom (TOF) for water gas-shift reaction at 323–393 K by 60–90 times larger than those of Pt nanoparticles in FSM-16 and even conventional metal catalysts.
87 citations
TL;DR: In this paper, the authors make suggestions with regard to the active centres for various reactions of syngas, including methanol and higher alcohol synthesis, and discuss the mechanism of the reactions and of the promoter function.
86 citations
TL;DR: Copper(II) terephthalate is the first transition metal complex found capable of adsorbing gases as mentioned in this paper, and it is recognized as the lead complex in the construction of microporous complexes.
76 citations
References
More filters
TL;DR: The adsorption of CO on Ni at 300 °C is dissociative, resulting in disproportionation to CO2 and a NiC species as mentioned in this paper, and the adsorbed CO is inert to H2.
280 citations
TL;DR: When used as a catalyst for conversion of synthesis gas at pressures above 25 atm, supported rhodium produces two-carbon oxygen-containing compounds, specifically acetic acid, acetaldehyde, and ethanol, with chemical efficiencies on the order of 50% as discussed by the authors.
256 citations
TL;DR: In this article, the infrared spectra of carbon monoxide adsorbed on supported PdAg alloys were investigated, and three CO absorption bands were observed on Pd and on the alloys at ~2060, 1960 and 1920 cm−1.
213 citations
TL;DR: In this paper, a series of Pd SiO 2 catalysts (2 wt% Pd) with and without a promoting additive were used as promoters, and it appeared that promoters (i) influence the activity of the catalysts and (ii) increase the selectivity for "oxygenates" and suppress the selectivities for CH4.
206 citations
TL;DR: In this article, a small amount of methanol was also produced over the pyrolysed catalysts of smaller Rh, Pt, and Ir carbonyl clusters on ZnO, MgO, CaO, and BeO.
Abstract: Methanol synthesis by the catalytic hydrogenation of carbon monoxide proceeded under atmospheric pressure and at 150–250 °C over rhodium, platinum and iridium crystallite catalysts, prepared from well-defined Rh, Pt, and Ir carbonyl cluster compounds highly dispersed on ZnO and MgO. The activity and selectivity of methanol formation depended considerably on the kind of metal carbonyl clusters and metal oxides employed as inorganic carriers. The catalysts prepared by the pyrolysis of smaller Rh, Pt, and Ir carbonyl clusters on ZnO, MgO, CaO, and BeO exhibited a higher selectivity of methanol synthesis. A small amount of ethanol was also produced besides methanol in CO–H2 reaction over the pyrolysed catalysts of Rh carbonyl clusters on MgO, CaO, and BeO. Other metal oxides such as SiO2 gel, γ-Al2O3, SnO2, and WO2 were employed for preparation of the dispersed Rh catalysts from carbonyl clusters, which catalysed mainly formation of methane and higher hydrocarbons with negligible selectivity of the oxygenated...
178 citations