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Supported metals future studies

The examples introduced above refer to the characterization of the most common types of catalysts, usually supported metals or single, mixed, or supported metal oxides. Many other materials such as alloys [199,200], carbides [201-203], nitrides [204,205], and sulfides [206] are also frequently used in catalysis. Moreover, although modem surface science studies with model catalysts were only mentioned briefly toward the end of the review, this in no way suggests that these are of less significance. In fact, as the ultimate goal of catalyst characterization is to understand catalytic processes at a molecular level, surface studies on well-defined model catalysts is poised to be central in the future of the field [155,174], The reader is referred to the Chapter 10 in this book for more details on this topic. [Pg.27]

Strength (FLS) empirical approach are discussed in Section 3 as methods for determining the molecular structures of metal-oxide species from their Raman spectra. The state-of-the-art in Raman instrumentation as well as new instrumental developments are discussed in Section 4. Sampling techniques typically employed in Raman spectroscopy experiments, ambient as well as in situ, are reviewed in Section S. The application of Raman spectroscopy to problems in heterogeneous catalysis (bulk mixed-oxide catalysts, supported metal-oxide catalysts, zeolites, and chemisorption studies) is discussed in depth in Section 6 by selecting a few recent examples from the literature. The future potential of Raman spectroscopy in heterogeneous catalysis is discussed in the fmal section. [Pg.103]

The future of Raman spectroscopy in the research and the development of catalysts appears to be extremely promising. The recent revolution in Raman instrumentation has dramatically increased the ability to detect weak Raman signals and to collect the data in very short times. Thus, it is now possible to perform real-time Raman analysis and to study many catal) c systems that give rise to unusually weak Raman signals. The enormous strides in Raman instrumentation now allow for the characterization of a wide range of catalytic materials bulk mixed oxides, supported metal oxides, zeolites, supported metal systems, metal foils, as well as single crystal surfaces. Few Raman studies have been reported for sulfides, nitrides, or carbides, but these catalytic materials also give rise... [Pg.149]

Even for an SMSI oxide, the extent of interaction is dependent on many parameters and a comparison among samples must be done systematically. Under high reduction temperatures encapsulation of the metal particle leads to a decline in CO hydrogenation in niobia-containing support. The niobia-silica surface phase oxide, which shows a similar mechanism of interaction to niobia but is less interacting, should prove useful as a model system in future studies. [Pg.134]

This study supports rate-determining H-OH bond breaking, which constrasts with previous reports that identified vinylidene isomerization as the key step in catalytic alkyne activation. The results indicate an enzyme-like mechanism is operative involving cooperative substrate activation by a metal center and proximal hydrogen bond donor/acceptors. In the future we will apply these principles to the activation of additional species. [Pg.240]

Similar results have been obtained with other ketones such as 2-octanone, acetophenone, and benzophenone. The basis for catalyst deactivation remains under study, together with alternative fiuoropolymer supports [59]. Analogous adsorption phenomena have been found with other fiuorous metal complexes, as will be detailed in future reports. In our opinion, there are many additional possible applications for this catalyst recovery/dehvery technology, and these are under active pursuit. [Pg.83]


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See also in sourсe #XX -- [ Pg.36 , Pg.157 , Pg.158 , Pg.159 ]




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