Gold Nanoparticles as Catalysts

J. Luo, M. M. Maye, Y. Lou, L. Han, M. Hepel, and C. J. Zhong, Catalytic activation of core-shell assembled gold nanoparticles as catalyst for methanol electrooxidation, Catal. Today 77,127-138 (2002). 

Tsunoyama, H., Sakurai, H., Ichikuni, N., Negishi, Y. and Tsukuda, T. (2004) Colloidal gold nanoparticles as catalyst for carbon-carbon bond Formation Application to aerobic homocoupling of phenylboronic acid in water. Langmuir, 20, 11293-11296. 

Prasad, B. L. V., Stoeva,S. I., et al. Gold Nanoparticles as Catalysts for Polymerization of Alkylsilanes to Siloxane Nanowires, Filaments, and Tubes. Journal of the American Chemical Society,125(35), 10488-10489 (2003). 

Corma, A. and Garcia, H. (2008) Supported gold nanoparticles as catalysts for organic reactions. Chemical Society Reviews, 37 (9), 2096-2126. 

M.J. Climent, J.C. Hernandez, A.B. Hungria, S. Iborra, S. Martinez-Silvestre, Biomass into chemicals one-pot two- and three-step synthesis of quinaxolines from biomass-derived glycols and 1,2-dinitrobenzene derivatives using supported gold nanoparticles as catalyst, J. Catal. 292 (2012) 118-129. 

H. Tsunoyama, H. Sakurai, N. Ichikuni, Y. Negishi, T. Tsukuda, 2004, Colloidal Gold Nanoparticles as Catalyst for Carbon-Carbon Bond Formation Application to Aerobic Homocoupling of Phenylboronic Acid in Water, Langmuir, 20, 11293-11296. 

So, M., Liu, Y, Ho, C., et al. (2009). Graphite-Supported Gold Nanoparticles as Efficient Catalyst for Aerobic Oxidation of Benzyhc Amines to Imines and N-Substituted 1,2,3,4-Tetrahydroisoquinolines to Amides Synthetic Apphcations and Mechanistic Study, Chemistry —An Asian Journal, 4, pp. 1551-1561. 

Figure 10.5 Photographs of 4-nitroaniline solution and the solution after reduction, and successive UV-vis absorption of the reduction of l-nitroaniline hy excess NaBH4 using pillar[5]arene-stabilized gold nanoparticles as the catalyst.

In the last 15 years, the application of supported metal nanoparticles as catalysts in organic synthesis has received a renewed interest. The association between a metal and a support could result in synergistic effects which would precisely drive the reactivity of these nanocatalysts, e.g. supported-gold NPs for the oxidation of carbon monoxide [127]. The recyclability and recovery from the reaction medium still remains one of the major drawbacks to a widespread use of NPs in catalysis. To overcome these problems, the immobilization of MNPs on solid supports appears as a promising alternative. Synthetic methods are also developed to achieve the direct synthesis of MNPs in the presence of a support in a controlled manner. Intensive work is made on the functionalization of the support to increase the anchorage of the particles, inspired by the ligands which are used to stabilize MNPs in solution. 

Zhong C-J and Maye M M (2001) Core Shell assembled nanoparticles as catalysts, Adv. Mater., 13, pp. 1507-1511. Zhong C-J, Luo J, Maye M M, Han L and Kariuki N N (2003) Nanostructured Gold and Alloy Electrocatalysts, in B Zhou, S Hermans, G A Somorjai (Eds.), Nanotechnology in Catalysis, KlutverAcademic/Plenum Publishers, (Chapter... 

Gold nanoparticles and gold(lll) complexes as general and selective hydrosilylation catalysts. Angewandte Chemie International Edition, 46, 7820. 

Density Functional Theory (DFT) has shown that low-coordinated sites on the gold nanoparticles can adsorb small inorganic molecules such as O2 and CO, and the presence of these sites is the key factor for the catal5dic properties of supported gold nanoclusters. Other contributions, induced by the presence of the support, can provide parallel channels for the reaction and modulate the final efficiency of Au-based catalysts. Also these calculations extended for the adsorption of O and CO on flat and... 

After supporting these sols on activated carbon, however, the obtained particle size depends on the capability of the protective agent to maintain the particle dimension. The obtained three catalysts, having different characteristics, are summarized in Table 3. As it is shown, mean size of gold nanoparticle obtained by TEM measurement did not always match with X-ray powder diffraction (XRPD) data. This result is not surprising as TEM measurements represent particle sizes, whereas from X-ray diffraction (XRD) it is possible to obtain crystallite dimensions that do not necessarily coincide with the size of... 

Three series of Au nanoparticles on oxidic iron catalysts were prepared by coprecipitation, characterized by Au Mossbauer spectroscopy, and tested for their catalytic activity in the room-temperature oxidation of CO. Evidence was found that the most active catalyst comprises a combination of a noncrys-taUine and possibly hydrated gold oxyhydroxide, AUOOH XH2O, and poorly crystalhzed ferrihydrate, FeH0g-4H20 [421]. This work represents the first study to positively identify gold oxyhydroxide as an active phase for CO oxidation. Later, it was confirmed that the activity in CO2 production is related with the presence of-OH species on the support [422]. 

Charged polysaccharides can also serve as templates for the growth of metallic, semiconductor and magnetic nanoparticles. For instance, chitosan has been reported as a catalyst and stabilizing agent in the production of gold nanoparticles by the reduction oftetrachloroauric (III) acid by acetic acid. The biopolymer controls the size and the distribution of the synthesized Au nanoparticles and allows the preparation... 

Maye et al. studied gold nanoparticles supported on carbon black for ORR in both acidic and alkaline media.210 The gold nanoparticles were of a core-shell type where the particle consisted of a gold nanocrystal core of 1-6 nm in diameter that was surrounded by an organic monolayer shell.214 While the Au/C catalyst was found to be active for ORR, its activity was much lower than that of Pt/C, PtRu/C and AuPt/C. The electron transfer in 0.5 M H2S04 was reported as 2.9 0.2, indicating a mixed reduction pathway.210... 

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