Nanoparticles methanol oxidation

Figure 12. Cyclic voltammograms of direct methanol oxidation catalyzed by the porous Pt nanoparticle membrane and as-made Pt nanoparticles. The reaction solution was made of an aqueous mixture containing O.IMHCIO4 and 0.125 M methanol. (Reprinted with permission from Ref [31], 2005, Wiley-VCH.)...

The FTIR studies revealed that the formation of CO2 is only detected when the CO starts to be oxidized (Fig. 6.18). Therefore, it was proposed that the mechanism has only one path, with CO as the C02-forming intermediate [Chang et al., 1992 Vielstich and Xia, 1995]. This has two important and practical consequences. First, methanol oxidation will be catalyzed by the same adatoms that catalyze CO oxidation, mainly ruthenium. Second, since the steric requirements for CO formation from methanol are quite high, the catalytic activity of small (<4nm) nanoparticles diminishes [Park et al., 2002]. 

Hernandez J, Solla-Gullon J, Heirero E, Aldaz A, Feliu JM. 2006. Methanol oxidation on gold nanoparticles in alkaline media Unusual electrocatalytic activity. Electrochim Acta 52 1662-1669. 

Lanova B, Wang H, Baltruschat H. 2006. Methanol oxidation on carbon supported Pt and Ru-modified Pt nanoparticles A comparison with single crystal and polycrystaUine electrodes. Euel Cells 3/4 214-224. 

Santhosh, P., A. Gopalan, and K.-P. Lee, Gold nanoparticles dispersed polyaniline grafted muttiwall carbon nanotubes as newer electrocatalysts Preparation and performances for methanol oxidation. Journal of Catalysis, 2006. 238(1) p. 177-185. 

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... 

Platinum, ruthenium and PtRu alloy nanoparticles, prepared by vacuum pyrolysis using Pt(acac)2 and Ru(acac)3 as precursors, were applied as anode catalysts for direct methanol oxidation . The nanoparticles, uniformly dispersed on multiwaUed carbon nanotubes, were all less than 3.0 nm in size and had a very narrow size distribution. The nanocomposite catalysts showed strong electrocatalytic activity for methanol oxidation, which can... 

The preparation, atomic and electronic structure, adsorption and reaction properties of metal nanoparticles supported on AljOj/NiAlCllO) were thoroughly explored by Freund and coworkers [11, 43, 52], Most studies were carried out under UHV, including CO dissociation on Rh nanoparticles [39], alkene hydrogenation [53], and CO and methanol oxidation [52],... 

Fig. 15.12 Methanol oxidation on Pd-Al O (mean particle size 6 nm) and Pd(lll) [27, 50, 75]. (a) In situ steady-state PM-IRAS and SFG spectra, shown together with the CHjOH conversion as monitored by gas chromatography, (b) Comparison of Pd3d XP spectra obtained before upper) and after (lower) the methanol oxidation reaction indicated a partial oxidation of Pd nanoparticles during the reaction, whereas Pd(lll) remained metalhc adapted in part from [75] with permission. Copyright (2007) The PCCP Owner Societies, (c) PM-IRAS (p-s) surface vibrational spectra measured during CH OH decomposition on Pd(lll) at 300 K, with the various species indicated. The time-dependent evolution of CH O (as observed by PM-IRAS) and of CH (values deduced from XPS) upon methanol decomposition at -lO mbar suggests a correlation between the two species adapted in part from [27] with permission. Copyright (2005) American Chemical Society, (d) Suggested mechanism of CH OH decomposition and oxidation on Pd catalysts reprinted [50] with permission. Copyright (2007) Elsevier...

Nitani H, Nakagawa T, Daimon H, Kurobe Y, Ono T, Honda Y, Koizumi A, Seino S, Yamamoto TA (2007) Methanol oxidation catalysis and substructure of PtRu bimetallic nanoparticles. Appl Catal A Gen 326 194... 

The role of metal-support interaction on the catalytic activity of carbon-supported Pt nanoparticles toward oxygen reduction and methanol oxidation was analyzed. It was observed that both dispersion and specific activity are influenced by the interaction of the active phase with the support, determining well-defined relationships that may be used for interpreting the electrochemical behavior of new, more advanced catalytic systems. 

Zhong and co-workers [530] described recent results of an investigation of the electrocatal3dic oxidation of methanol using carbon-supported An and Au-Pt nanoparticle catalysts. The exploration of the bimetallic composition on carbon black support was aimed at modifying the catalytic properties for the methanol oxidation reaction at the anode in direct methanol fuel cells (DMFCs). An and Au-Pt nanoparticles of 2-3 nm sizes encapsulated in an organic monolayer were prepared, assembled on carbon black materials and treated thermally. The results have revealed that these Au-Pt nanoparticles catalysts are potentially viable candidates for use in fuel cells under a number of conditions [530],... 

Wieckowski et al. reported the spontaneous deposition Ru adlayers from RuO" solutions on three low-index Pt surfaces. The maximum coverage of Ru on these adlayer is about 20%, and potential must be applied to reduce the Ru adlayer to metallic Ru. The Ru-decorated Pt nanoparticles showed considerable catalytic activity in the methanol- oxidation reaction. We will discuss the catalytic properties of the Ru-decorated Pt nanoparticles in Section V.3. 

From libraries of pulsed electrodeposited platinum (Pt) doped WO3, whereby a new means of creating nanoparticles has been developed. The nanoparticles show high activity for methanol oxidation without the poisoning problems of Pt... 

Carbon-supported bimetallic or even ternary catalysts are of increasing interest in electrocatalytic reactions such as methanol oxidation. In this sense, the preparation routes are of pristine importance in determining the catalytic performance. As an example, it has been shown that Pt/Rn/Ni = 5 4 1 nanoparticles have a higher catalytic activity for methanol electrooxidation than does Pt/Ru = 1 1... 

Pig.l shows the results obtained with the Pe containing sample prepared using hexacarbonyl triiron (see Table 1) as a precursor. Similarly to the case of CO oxidation, TOP values for methanol oxidation are noticeably dependent of the total metal loading. This also could be due to the intracrystalline agglomeration of iron oxide nanoparticles that... 

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