CO Oxidation over a Pt/CoOx/SiO2Catalyst: A Study Using Temporal Analysis of Products

Mergler, Y.J.; Hoebink, Jhbj Jozef; Nieuwenhuys, BE Bernard

doi:10.1006/jcat.1997.1599

Cited by 77 publications

(28 citation statements)

References 19 publications

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“…Even at room temperature CO is oxidized. The high activity of Pt/CoOx/SiO2 in CO oxidation is related to the absence of CO inhibition effects at low temperatures (22). At temperatures up to about 200°C Pt surfaces are almost inactive for CO oxidation because the whole Pt surface is covered with CO.…”

Section: Synergistic and Particle Size Effectsmentioning

confidence: 99%

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Catalysis by Gold Nanoparticles

et al. 2002

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Gold catalysts have superior activity in CO and other oxidations at low temperatures. Both a small (~5nm) particle size and the presence of a partly reducible oxide (ceria or a transition metal oxide) have a beneficial effect on the catalyst performance. The present paper reviews our recent studies focused on understanding the specific role of the Au particle size and that of the oxide (MO). Our personal viewpoint on gold catalysis is outlined. The effects of Au particle size and of the oxidic additive are distinguished by using several alumina-supported gold catalysts having different gold particle sizes and various oxidic additives. The most active catalyst in CO oxidation is the multicomponent catalyst Au/MgO/MnOx/Al2O3 with MgO being a stabilizer for the Au particle size and MnOx being the cocatalyst. This catalyst also exhibits good performance in selective oxidation of CO in a hydrogen atmosphere, a reaction relevant for the development of polymer electrolyte fuel cell technology.In its bulk form, gold has been regarded to be chemically inert towards chemisorption of reactive molecules such as oxygen and hydrogen. Consequently, pure gold was considered to be an uninteresting metal from the point of view of catalysis. The most noticeable exception to this was its use as a 'diluent' for an active metal: the addition of the inert gold to an active metal such as platinum affects to a significant extent the selectivity of the catalyst (1). However, recently, gold catalysts have attracted a dramatic growth of interest, since gold was reported to be extremely active in the oxidation of carbon monoxide if deposited as nanoparticles on partly reducible oxides. It is in particular the pioneering work of Haruta et al, which has stimulated research in this area (2). Early work performed with gold catalysts has been reviewed by Bond (3) and by Hutchings (4). For recent reviews on gold catalysis see references 2 and 5 -7.A large range of chemical reactions are now known to be catalysed by gold catalysts including total and selective oxidation, and reduction of nitrogen oxides. Based on the growth of the number of papers and patents dealing with gold-based catalysts for a range of potential applications in pollution control, chemical processes and development of fuel cells, it can be concluded that there may be a bright future for gold-based catalysis.In the present paper we discuss some of our research on catalysis by gold (8 -14), and in particular, the following topics will be discussed: a) the effect of the gold particle size and the role of the oxidic additive; b) the selective oxidation of CO in the presence of hydrogen, a reaction relevant to hydrogen fuel cell applications. ExperimentalAll the catalysts discussed in this paper are supported on γ-alumina, the gold loading is 5.0 wt%. The gold catalysts were prepared by homogeneous deposition precipitation using urea as precipitating agent. The advantage of the use of alumina as support is the high stability of the catalysts up to relatively high temperatures (10, ...

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Section: Synergistic and Particle Size Effectsmentioning

confidence: 99%

“…It is likely that the reaction takes place at the Pt-MOx interface (22). Some of the gold-based catalysts are clearly superior to the Pt-based catalysts.…”

Section: Synergistic and Particle Size Effectsmentioning

confidence: 99%

Catalysis by Gold Nanoparticles

et al. 2002

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“…Cobalt-oxide-based materials have been identified as preferred catalysts for environmental protection processes such as the abatement of CO [1,2], N 2 O decomposition [3,4], and phenol degradation [5]. Recently, these materials have been widely investigated with the aim of improving their catalytic properties [6].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of flower-like Co3O4–CeO2 composite oxide and its application to catalytic degradation of 1,2,4-trichlorobenzene

Lin

Zheng

et al. 2012

Applied Catalysis B: Environmental

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a b s t r a c tA micrometer-sized, nanostructured, flower-like Co 3 O 4 -CeO 2 composite oxide was synthesized by an ethylene-glycol-mediated process. The composite oxide was an assembly of polycrystalline nanoparticles, with a typical mesoporous structure. The composite's catalytic activity in 1,2,4-trichlorobenzene degradation was evaluated using a pulsed-flow microreactor-gas chromatography system, and compared with that of quartz sand, commercial CeO 2 , commercial Co 3 O 4 , and a Co 3 O 4 /CeO 2 equimass mixture. The composite oxide was a promising catalyst for 1,2,4-trichlorobenzene degradation. This is attributed to the structural features of the composite oxide with a high specific surface area and a high total pore volume, and the synergistic effect between the two composite phases. The easy creation of high-mobility active oxygen on CeO 2 and the easy cleavage of Co O bonds at the interface of the two components promote reactivity of Co 3 O 4 in 1,2,4-trichlorobenzene degradation. Pulsed catalytic theory suggests a first-order reaction between the composite oxide and 1,2,4-trichlorobenzene, with an apparent activation energy of about 27 kJ/mol, and degradation on the Co 3 O 4 -CeO 2 composite oxide would occur easily.

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“…Co 3 O 4 is very attractive for applications involving oxidation reactions because of the presence of mobile oxygen, such as the use of unsupported cobalt oxide as an active catalyst in air pollution control for the abatement of CO [12], NO x [13] and organic pollutants from effluent streams [14]. Co 3 O 4 is an important magnetic p-type semiconductor, which belongs to the normal spinel crystal structure based on a cubic close packing array of oxide ions, in which Co(II) ions occupy the tetrahedral 8a sites and Co(III) ions occupy the octahedral 16d sites [15].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Co3O4 nanoparticles by oxidation-reduction method and its magnetic characterization

et al. 2009

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Without any surfactant, antiferromagnetic Co 3 O 4 nanoparticles were synthesized successfully for the first time by means of an oxidation-reduction method with cobalt sulfate as starting material, which was oxidized to cobalt salt by NaNO 3 after alkalinizing with NaOH. Morphological, structural, spectroscopic and magnetic characterization of the product were done by SEM, TEM, XRD, and VSM, respectively. The average crystallite size (on the base of line profile fitting method), D and σ, is estimated as 30 ± 6 nm. Some anomalous magnetic properties and their enhanced effect have been observed in Co 3 O 4 antiferromagnetic nanocrystallites, including a bias field, coercivity, permanent magnetic moments and an open loop. These phenomena are attributed to the unidirectional anisotropy which is caused by the exchange coupling between AFM and FM layers, the existence of the spin glass like surface spins of Co 3 O 4 nanoparticles due to size effects and surface-area effect.© Versita Warsaw and Springer-Verlag Berlin Heidelberg.

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CO Oxidation over a Pt/CoOx/SiO2Catalyst: A Study Using Temporal Analysis of Products

Cited by 77 publications

References 19 publications

Catalysis by Gold Nanoparticles

Catalysis by Gold Nanoparticles

Synthesis of flower-like Co3O4–CeO2 composite oxide and its application to catalytic degradation of 1,2,4-trichlorobenzene

Synthesis of Co3O4 nanoparticles by oxidation-reduction method and its magnetic characterization

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