Catalysis: New Perspectives from Surface Science

Abstract

One-sixth of the value of all goods manufactured in the United States involves catalytic processes. However, in spite of this dramatic economic impact, little is known about this broad subject at the molecular level. In the last two decades a variety of techniques have been developed for studying at the atomic level the structure, composition, and chemical bonding at surfaces. These techniques have been used to study adsorption and reaction on metal single crystals in an ultrahigh vacuum environment or to analyze catalysts before and after reaction. An important new development has been the coupling of an apparatus for the measurement of reaction kinetics at elevated pressures with an ultrahigh vacuum system for surface analysis. This approach has demonstrated that metal single crystals can be used to successfully model many important catalytic reactions and has established a direct link between the results of ultrahigh vacuum surface measurements and the chemistry that occurs under typical catalytic-processing conditions.

Addition of Pt(IPr) Groupings to Ru5 Carbide Gives New Mixed-Metal Pt–Ru Cluster Complexes

“…Studies have shown that certain bimetallic catalysts have both higher activity and better product selectivity than their monometallic counterparts [18][19][20][21], and mixedmetal cluster complexes are found to be good precursors for the preparation of supported bimetallic nanoparticles [22][23][24][25]. Cluster complexes of platinumruthenium immobilized on mesoporous silica have been shown to exhibit high activity for catalytic hydrogenation reactions [18,[26][27][28].…”

Mixed-metal cluster chemistry. 39. Syntheses and X-ray structures of Mo 3 Ir 3 (μ 4 -η 2 -CO)(μ 3 -CO)(CO) 10 (η 5 -C 5 H 5 ) 3 and Mo 3 RhIr 3 (μ-CO) 4 (CO) 7 (η 5 -C 5 H 5 ) 3 (η 5 -C 5 Me 5 )

“…[1][2][3] The presence of differing transition metals may offer molecular approaches to the design of catalysts with high activity and selectivity, because the intrinsic polarity of heterometallic bonds may afford enhanced activation and direct the selectivity of substrate-cluster interactions. [4,5] Mixed-metal clusters can possess readily tailored physical properties (such as optical limiting) because of facile structural manipulation resulting from incorporation of differing metal atoms and the variation of the metal core skeletons, [6] so they continue to command attention.…”

Synthesis and Structural Characterization of Ruthenium Carbonyl Cluster Complexes Containing Platinum with a Bulky N-Heterocyclic Carbene Ligand

“…Mixed-metal cluster complexes have been shown to be good precursors for the preparation of supported bimetallic nanoparticles . It has been shown that certain bimetallic catalysts have both higher activity and better product selectivity than their monometallic counterparts . Supported platinum–ruthenium clusters have been shown to exhibit high activity for catalytic hydrogenation reactions when immobilized on mesoporous silica. , The use of NHCs in metal cluster chemistry is still relatively limited.…”