Catalyst supports carbon nanoparticle

Additional experiments were carried out to study the behavior of Pd nanoparticles coated with Pt or with Pt plus M, which more closely reflects the morphology of actual catalyst particles. Figure 9.18a displays the polarization curves for the ORR on commercial carbon-supported Pt nanoparticles (Pt/C), Pd nanoparticles (Pd/C), a monolayer of Pt on Pd/C (PtMu/Pd/C), and mixed (Pto.gIro.a/ML/Pd/C and... 

One of the critical issues with regard to low temperamre fuel cells is the gradual loss of performance due to the degradation of the cathode catalyst layer under the harsh operating conditions, which mainly consist of two aspects electrochemical surface area (ECA) loss of the carbon-supported Pt nanoparticles and corrosion of the carbon support itself. Extensive studies of cathode catalyst layer degradation in phosphoric acid fuel cells (PAECs) have shown that ECA loss is mainly caused by three mechanisms ... 

Methanol, Formaldehyde, and Formic Acid Adsorption/Oxidation on a Carbon-Supported Pt Nanoparticle Fuel Cell Catalyst A Comparative Quantitative OEMS Study... 

A similar inhibition was found also for electrochemical CO oxidation. In COad stripping experiments, numerous potential cycles up to IV were necessary to remove all COad from a smooth Ru(OOOl) surface [Zei and Ertl, 2000 Lin et al., 2000 Wang et al., 2001]. CO bulk oxidation experiments under enforced mass transport conditions on polycrystalline Ru [Gasteiger et al., 1995] and on carbon-supported Ru nanoparticle catalysts [Jusys et al., 2002] led to similar results. Hence, COad can coexist with nonreactive OHad or Oad species on Ru(OOOl) at lower potentials (E < 0.55 V) [El-Aziz and Ribler, 2002]. 

Yoon, H., Ko, S. and Jang, J. (2007) Nitrogen-doped magnetic carbon nanoparticles as catalyst supports for efficient recovery and recycling. Chemical Communications (14), 1468-1470. 

Kinetic analysis with a Langmuir-type rate equation (Equation 13.4) [37] gave us the magnitudes of reaction rate constant (k) and retardation constant due to product naphthalene (K) for the superheated liquid film (0.30 g/1.0 mL) and the suspended states (0.30 g/3.0 mL) with the same Pt/C catalyst as summarized in Table 13.2. It is apparent that excellent performance with carbon-supported platinum nanoparticles in the superheated liquid-film state is realized in dehydrogenation catalysis on the basis of reaction rate and retardation constants. 

Siamaki, A.R., et ah, Microwave-assisted synthesis of palladium nanoparticles supported on graphene A highly active and recyclable catalyst for carbon-carbon cross-coupling reactions. Journal of Catalysis, 2011. 279(1) p. 1-11. 

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... 

Among the supports that have been used in the preparation of supported transition metal nanoparticles are carbon, silica, alumina, titanium dioxide, and polymeric supports [57], and the most frequently used support is alumina [56], These supports normally produce an effect on the catalytic activity of the metallic nanoparticles supported on the amorphous material [60], In Chapter 3, different methods for the preparation of metallic catalysts supported on amorphous solids were described [61-71],... 

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. 

Bezerra et al extensively reviewed heat treatment and stability effects of various Pt/C, Pt-M/C, and C-supported Pt-free alloy catalysts, taking into account particle sizes and stiuctural parameters. Appropriate heat treatment of Pt/C catalysts improves ORR activity by stabilizing the carbon support against corrosion, which in turn increases the cathode life time. Depositing mixed-metal Pt monolayers on carbon-supported metal nanoparticles or Pt monolayers on noble/non-noble core-shell nanoparticles leads to enhanced electrode performance. RRDE experiments on the catalytic activity of Pt-M (M = Au, Pd, Rh, Ir, Re or Os) monolayers on carbon-supported Pd nanoparticles showed that an 80 20 PtiM ratio for the nuxed monolayers performs better than commonly nsed Pt/C catalysts. ... 

These difficulties have stimulated the development of defined model catalysts better suited for fundamental studies (Fig. 15.2). Single crystals are the most well-defined model systems, and studies of their structure and interaction with gas molecules have explained the elementary steps of catalytic reactions, including surface relaxation/reconstruction, adsorbate bonding, structure sensitivity, defect reactivity, surface dynamics, etc. [2, 5-7]. Single crystals were also modified by overlayers of oxides ( inverse catalysts ) [8], metals, alkali, and carbon (Fig. 15.2). However, macroscopic (cm size) single crystals cannot mimic catalyst properties that are related to nanosized metal particles. The structural difference between a single-crystal surface and supported metal nanoparticles ( 1-10 nm in diameter) is typically referred to as a materials gap. Provided that nanoparticles exhibit only low Miller index facets (such as the cuboctahedral particles in Fig. 15.1 and 15.2), and assuming that the support material is inert, one could assume that the catalytic properties of a... 

What, if any, relevance do such results have when predicting the influence of adsorbed bismuth on the CO of supported platinum nanoparticle catalysts In order to test the transferrability of results obtained on single crystals to practical fuel-cell anode catalysts, a series of experiments was performed [77] on a gas diffusion electrode of carbon-supported platinum (0.22 mg cm ) catalyst (Johnson Matthey). Figure 10 shows the results of polarization measurements for hydrogen oxidation at clean and bismuth-modified (0.65-ML) catalysts. In order to establish the CO tolerance of the electrodes, in addition to experiments involving pure H2,... 

Sinfelt has greatly contributed to the catalyses of bimetallic nanoparticles [18]. His group has thoroughly studied inorganic oxide-supported bimetallic nanoparticles for catalyses and analyzed their microstructures by an EXAFS technique [19-22]. Nuzzo and co-workers have also studied the structural characterization of carbon-supported Pt/Ru bimetallic nanoparticles by using physical techniques, such as EXAFS, XANES, STEM, and EDX [23-25]. These supported bimetallic nanoparticles have already been used as effective catalysts for the hydrogenation of olefins and carbon-skeleton rearrangement of hydrocarbons. The alloy structure can be carefully examined to understand their catalytic properties. Catalysis of supported nanoparticles has been studied for many years and is practically important but is not considered further here. 

Interaction of Metal Complexes as Catalyst Precursors with Carbon Supports and Its Influence on the State of Supported Metal Nanoparticles Produced... 

INTERACTION OF METAL COMPLEXES AS CATALYST PRECURSORS WITH CARBON SUPPORTS AND ITS INFLUENCE ON THE STATE OF SUPPORTED METAL NANOPARTICLES PRODUCED... 

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