Supports gold nanoparticles

Correlation has been suggested between the morphology, electronic structure and catalytic properties of supported gold nanoparticles with special attention to the role of the substrate/interface behaviour. 

Guerin S, Hayden BE, Pletcher D, Rendall ME, Suchsland J-P, WiUiams LJ. 2006b. Combinatorial approach to the study of particle size effects in electrocatalysis synthesis of supported gold nanoparticles. J Comb Chem 8 791-798. 

Hayden BE, Pletcher D, Suchsland J-P. 2007. Enhanced activity for electrocatal)4ic oxidation of carbon monoxide on titania-supported gold nanoparticles. Angew Chem Int Ed 46 3530-3532. 

S.Schimpf, M. Lucas, C. Mohr, U.Rodemerck, A. Bruckner, J.Radnik, H. Hofmeister, andR Claus, Supported gold nanoparticles in-depth catalyst characterization and application in hydrogenation and oxidation reactions, Catal. Today 72(1—2), 63—78 (2002). 

The electrocatalytic activity of the nanostructured Au and AuPt catalysts for MOR reaction is also investigated. The CV curve of Au/C catalysts for methanol oxidation (0.5 M) in alkaline electrolyte (0.5 M KOH) showed an increase in the anodic current at 0.30 V which indicating the oxidation of methanol by the Au catalyst. In terms of peak potentials, the catalytic activity is comparable with those observed for Au nanoparticles directly assembled on GC electrode after electrochemical activation.We note however that measurement of the carbon-supported gold nanoparticle catalyst did not reveal any significant electrocatalytic activity for MOR in acidic electrolyte. The... 

Unique Catalytic Performance of Supported Gold Nanoparticles in Oxidation... 

An(acac)(Me)2 was nsed by Clans and coworkers to produce silica-supported gold nanoparticles by MOCVD , as a catalyst with Au content of 2.4 wt% and average Au particle size of 1.4 nm, which fits well to other supported gold catalysts prepared from alternative precnrsors by different rontes . The supported nanoparticles were applied as catalyst for low-temperatnre oxidation of carbon monoxide. 

Gold nanoparticles have received significant attention in recent years because of their unique catalytic activity [37 3]. Supported gold nanoparticles in the range of 2-5 nm are effective as catalysts for a variety of reactions including selective oxidation of propane to propylene oxide [44] and low-temperature CO oxidation [45]. Numerous experimental studies have focused on understanding the effect of particle size in gold catalysts however, the picture is often complicated by the lack of a monodisperse size distribution. 

Panigrahi S, Basu S, Praharaj S, Pande S, Jana S, Pal A, Ghosh SK, Pal T (2007) Synthesis and size-selective catalysis by supported gold nanoparticles study on heterogeneous and homogeneous catalytic process. J Phys Chem C 111 4596... 

D. G. Barton, S. G. Podkolzin, Kinetic study of a direct water synthesis over silica-supported gold nanoparticles, /. Phys. Chem. B 109 (2005) 2262. 

P Claus, A Bruckner, C Mohr and H Hofineister, Supported Gold Nanoparticles from Quantum Dot to Mesoscopic Size Scale Effect of Electronic and Structural Properties on Catalytic Hydrogenation of Conkugated Functional Groups, J. Am. Chem. Soc., 122,11430-11439,2000. 

For the preparation of gold nanopartides supported on insoluble solids, the most widely used procedure is the precipitation-deposition method [32-36]. Starting from an aqueous solution of HAuCh, addition of a base leads to precipitation of a mixture of Au(OH)3 and related oxy/hydroxides that adsorbs into the solid and is then reduced to metallic gold by boiling the adsorbed species in methanol or any other alcohol. In this procedure, it has been established that the pH of the precipitation and the other experimental conditions (nature of the alcohol, temperature and time of the reduction, calcination procedure, etc.) can provide a certain control of the particle size of the resulting nanoparticles [3j. Figure 12.2 illustrates the steps required in the formation of supported gold nanoparticles. 

Influence of the Support on the Catalytic Actiuity of Supported Gold Nanoparticles I 403... 

The currently most widely accepted reaction mechanism for alcohol oxidation catalyzed by supported gold nanoparticles has been proposed by analogy with the assumed reaction mechanism for alcohol oxidation in palladium and platinum metals taking into consideration the kinetic data and mechanistic information obtained from gold-catalyzed CO oxidation [110]. Scheme 12.11 illustrates a reasonable mechanistic proposal. 

Scheme 12.12 Pictorial representation of the formation of metal-alcoholate at the surface of ceria supported gold nanoparticles.

Scheme 12.15 Selective aerobic oxidation of glucose to gluconate catalysed by activated carbon supported gold nanoparticles in basic aqueous medium.

Fig. 13.3 SizeKjependent catalytic activity of supported gold nanoparticles in ethane-1,2-diol (EG) oxidation. [EG)=0.5M in...

Supported gold nanoparticles have been used in sorbitol oxidation and compared with analogous Pd and Pt catalysts [41]. The catalytic data for the monometallic catalysts are reported in Table 13.8. Using carbon as a support, the reaction took... 

Metallic nanoparticles have different applications in different types of fields. These particles have stmctures with optical and electronic properties. These particles can be used in electronic applications, for example, the positioning of individual molecules of lambda-DNA in an electrode gap (Sarma 2003). Metal nanoparticles have recently been found to be applicable in catalysis. Hamta (2004) have discovered that supported gold nanoparticles are extremely catalyti-cally active for carbon monoxide (CO) at temperatures much lower than room... 

Water-Gas Shift Reaction on Supported Gold Nanoparticles... 

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