Heterogeneous catalysis nanoclusters

The review is broken into three broad sections, each containing three separate topics. The first section highlights three dramatic successes in the application of DFT to heterogeneous catalysis, followed by a discussion of the accuracy of DFT. The second section reviews three areas within heterogeneous catalysis that have attracted large volumes of theoretical effort in recent years, namely ab initio thermodynamics, the catalytic activity of nanoclusters of gold, and the development of bimetallic catalysts. The third section provides recent... 

The success stories reviewed above are, of course, just several of a larger number of areas of heterogeneous catalysis in which DFT-based calculations have made valuable contributions in recent years. In this section, three topics that have attracted considerable attention are described, ab initio thermodynamics, the catalytic activity of nanoclusters of gold, and computational efforts to screen bimetallic catalysts. Again, the choice of these topics does not indicate that they are the only topics of interest in the community, but they give a good representation of current approaches. 

Heterogeneous catalysis probes mechanisms of reactions that typically occur on metallic nanoclusters supported on insulators such as transition metal oxides. These studies relate directly to many commercial processes such as oil refining, hydrogen production, and food processing. 

Finke et al. have developed for the past 10 years an original method for nanoparticies synthesis using organometallic cationic complexes attached to polyoxoanions as metal precursors. " A complete and detailed work has been performed to elucidate the mechanism of formation of the nanoclusters and to develop a general procedure to be able to distinguish homogeneous from heterogeneous catalysis. This research has been recently reviewed. ... 

Another example of metal(O) nanoparticles catalysts for the dehydrogenation of DMAB has been reported very recently, describing the preparation and characterization of ruthe-nium(O) nanoclusters stabilized by 3-aminopropyltriethoxysilane [74,208]. They were prepared reproducibly by the decomposition of [Ru(COD)(C OT)] (COD=l,5-cyclooctadiene and COT=1,3,5-cyclooctatriene) in THF under 3 bar H2 in the presence of 1 equivalent stabilizer per mole of Ru at room temperature and showed a TOP value of 55 h and a TTO value of 1240 in the dehydrogenation of DMAB at 25 C. The isolability and reusability of ruthenium(O) nanoparticles, two crucial criteria in heterogeneous catalysis, were also tested in the catalytic dehydrogenation of DMAB and it was found that they retain 76% of their initial activity and provide >99% of conversion at the sixth run in the dehydrogenation of DMAB at room temperature. More importantly, ruthenium(0) nanoparticles stabilized by... 

In the sixties of past century, a few patents issued to Bergbau Chemie [5,48,49] and to Mobil Oil [50-52], respectively described the use of CFPs as supports for catalytically active metal nanoclusters and as carriers for heterogenized metal complexes of catalytic relevance. For the latter catalysts the term hybrid phase catalysts later came into use [53,54], At that time coordination chemistry and organo-transition metal chemistry were in full development. Homogeneous transition metal catalysis was expected to grow in industrial relevance [54], but catalyst separation was generally a major problem for continuous processing. That is why the concept of hybrid catalysis became very popular in a short time [55]. 

Aiken, III, ID. Lin, Y., and Finke, R.G., A perspective on nanocluster catalysis polyoxonation and tetrabutylamonium stabilized Ir(> Vj0 nanocluster soluble heterogeneous catalysts, J. Mol. Catal. A,... 

Tii3-nanoclusters (Fig. 2.8) have been used as powerful activators for heterogeneous noble metal hydrogenation catalysis [9, 130]. In the so-called butyronitrile hydrogenation standard test the activity of surfactant-stabiUzed colloidal rhodium... 

Kon K, Hakim Siddiki SMA, Shimizu K. Size- and support-dependent Pt nanocluster catalysis for oxidant-free dehydrogenation of alcohols. J Catal. 2013 304 63-71. Shimizu K, Kon K, Shimura K, Hakim SSMA. Acceptor-firee dehydrogenation of secondary alcohols by heterogeneous cooperative catalysis between Ni nanoparticles and acid—base sites of alumina supports. J Catal. 2013 300 242-250. 

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