Selective oxidation of CO in the presence of H2, H2O and CO2via gold for use in fuel cells

Landon, Philip; Ferguson, J.; Solsona, Benjamín; Garcı́a, Tomás; Carley, Albert Frederick; Herzing, Andrew A.; Kiely, Christopher J.; Golunski, Stanislaw E.; Hutchings, Graham J.

doi:10.1039/b505295p

Cited by 159 publications

(120 citation statements)

References 18 publications

Supporting

Mentioning

102

Contrasting

Unclassified

Order By: Relevance

“…For example for TiO 2 -supported catalysts, deposition precipitation is used where the TiO 2 is stirred in an aqueous solution of a gold salt and base is added to precipitate the gold, [78][79][80][81][82] whereas Fe 2 O 3 -supported catalysts are prepared by coprecipitation from an aqueous solution of gold and iron salts. [83][84][85] These methods tend to synthesize a very broad range of gold nano-structures and until recently particles in the 2-5 nm range were considered to be the active species in these catalysts. 85 However, transmission electron microscopy has advanced rapidly, especially with the introduction of C. u-VOPO 4 transforms to d-VOPO 4 when exposed to a variety of reactants at 400 C. A further transformation of d-VOPO 4 into a disordered material was observed when butane or acetic acid was added in the absence of oxygen.…”

Section: Designing Supported Gold and Gold Palladium Catalystsmentioning

confidence: 99%

Heterogeneous catalysts—discovery and design

Hutchings

2009

J. Mater. Chem.

Self Cite

148

View full text Add to dashboard Cite

Heterogeneous catalysis plays a key role in the manufacture of essential products in key areas of agriculture and pharmaceuticals, but also in the production of polymers and numerous essential materials. Our understanding of heterogeneous catalysts is advancing rapidly, especially by using the latest characterisation methods on these relatively complex effect materials. At the heart of these catalytic processes, both selective oxidation and hydrogenation play a key role. Both oxidation and hydrogenation exhibit similar requirements since often a partial reaction product is required, rather than the products of total hydrogenation or oxidation, in the latter case this being typically carbon dioxide and water. This Feature Article considers the approaches available for catalyst discovery and design for heterogeneous catalysts. Three catalysts are considered in detail, two exemplifying oxidation and the other selective hydrogenation. The design of vanadium phosphates for the selective oxidation of butane to maleic anhydride is described in terms of the search for advanced materials with superior activity. This is achieved through the synthesis of wholly amorphous vanadium phosphates. The design of supported gold and gold palladium alloy catalysts for the oxidation of carbon monoxide and the direct hydrogenation of oxygen to form hydrogen peroxide is described and the problems concerning selectivity control are discussed.

show abstract

Section: Designing Supported Gold and Gold Palladium Catalystsmentioning

confidence: 99%

Heterogeneous catalysts—discovery and design

Hutchings

2009

J. Mater. Chem.

Self Cite

148

View full text Add to dashboard Cite

show abstract

“…Compared to Au/␥-Al 2 O 3 , multicomponent gold-based catalysts also supported on ␥-Al 2 O 3 and combined with common metal oxides, such as: MnO x , MgO, FeO x (9,10) as well as gold catalysts supported on other materials such as Au/TiO 2 (11) and Au/FeO x (11,12) have been found to exhibit even more promising commercial performance for the SCO reaction. However, based on its simplicity, a well-studied Au/␥-Al 2 O 3 catalyst (1,9) has been utilized in the present work as model system, in order to gain fundamental information on the catalytic behaviour of gold nanoparticles and identify the active sites on Au/␥-Al 2 O 3 .…”

Section: Introductionmentioning

confidence: 99%

On the mechanism of selective CO oxidation on nanosized Auγ-Al2O3 catalysts

et al. 2006

View full text Add to dashboard Cite

Nanometer-sized gold particles on oxide supports are efficient catalysts for the selective catalytic oxidation (SCO) of carbon monoxide under conditions compatible with the operation of PEM fuel cells. Nanosized Au/␥-Al 2 O 3 catalysts are able to oxidize CO between 20 and 70°C in an atmosphere of hydrogen combining high CO conversion and satisfactory selectivity to CO 2 (1). It is generally agreed that the catalytic activity of gold depends on the size of the gold particles, but the nature of support material, the preparation method, the activation procedure have also been suggested to play a key role (2). Sites at the gold support interface have also been claimed to be responsible for the activity in CO oxidation (3). Strain in the Au particles due to the mismatch of the lattices at the interface with the support (4) and the effect of low-coordinated sites and roughness (4) have also been suggested as important factors for high activity. The most important effect, concerning the catalytic activity of gold nanoparticles for low temperature oxidation of CO is related to the availability of many low-coordinated gold atoms on the small particles (5). Effects related to the interaction with the support may also contribute, but to a considerably smaller extent (5).CO oxidation over group VIII noble metals is the most studied catalytic reaction. However, selective oxidation of CO in hydrogen-rich conditions is not as well studied (6,7). CO (reactant) and CO 2 (product) sorption processes are fundamental elementary steps for SCO and moreover, the effect of hydrogen on their sorption over supported Au catalysts remains a subject of significant interest.Among the various supported Au catalysts, Au/Al 2 O 3 is perhaps one that has shown the widest variation for CO oxidation, ranging from being very inactive to practically as active as Au/TiO 2 (8). Compared to Au/␥-Al 2 O 3 , multicomponent gold-based catalysts also supported on ␥-Al 2 O 3 and combined with common metal oxides, such as: MnO x , MgO, FeO x (9,10) as well as gold catalysts supported on other materials such as Au/TiO 2 (11) and Au/FeO x (11,12) have been found to exhibit even more promising commercial performance for the SCO reaction. However, based on its simplicity, a well-studied Au/␥-Al 2 O 3 catalyst (1,9) has been utilized in the present work as model system, in order to gain fundamental information on the catalytic behaviour of gold nanoparticles and identify the active sites on Au/␥-Al 2 O 3 .In this paper, new findings which offer further information concerning the mechanism of CO preferential oxidation over nanosized Au are presented. The first finding concerns CO 2 formation in the absence of oxygen and hydrogen both in bare ␥-Al 2 O 3 as well as in Au/␥-Al 2 O 3 (called as CO decomposition). At high temperatures (>200 °C) in excess of H 2 , over the Au/␥-Al 2 O 3 catalyst, reversed water gas shift (RWGS) reaction results in CO 2 consumption towards CO and H 2 O formation. Finally, the kinetic measurements of the present work indicate that hydrog...

show abstract

“…The same is true for Au particles supported on oxides. Although the activity has been discussed in relation to particle size by assuming the competitive reaction of CO and H with O not only on supported metals [9][10][11][12] but also for the role of Au-cations, 10 the effect of calcination temperature, 11 and the activation of inactive Au/TiO 2 by covering with TiO x 12 but it is difficult to explain them without insight into the reaction mechanism. As shown in this paper, the PROX reaction of CO taking place on the FeOx/Pt/TiO 2 catalyst at low temperature is different from the ordinary oxidation reaction of CO with O 2 , i.e., the intermediates are completely different.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Characterization of the Intermediates for Low-Temperature PROX Reaction of CO in H₂—Oxidation of CO with OH via HCOO Intermediate

Tanaka

Shou

et al. 2009

J. Phys. Chem. C

View full text Add to dashboard Cite

/ 2 O 2 f CO 2 ) on a FeO x /Pt/TiO 2 catalyst (∼140 wt % FeO x on 1 wt % Pt/TiO 2 ) was studied at 60°C by using in situ DRIFT spectroscopy. The PROX reaction of CO occurs via a HCOO intermediate and its oxidation with OH instead of oxygen, which is different from ordinary oxidation of CO with O 2 (CO + 1 / 2 O 2 f CO 2 ). The mechanism is as follows: (i) CO(a) + OH -f HCOO + e, (ii) O + e + H + f OH, and (iii) HCOO + OH f CO 2 + H 2 O, and step (iii) is the rate-determining step. Providing HCOO intermediates by a reaction of CO(a) with the OH -anion, step (i), was deduced by combining an electroconductive PROX catalyst (Pt/CNT(carbon nanotube)) with a hydrogen fuel cell. The oxidation of CO enhanced by H 2 and H 2 O and the hydrogen isotope effect by H 2 /D 2 and H 2 O/ D 2 O on the FeO x /Pt/TiO 2 catalyst are well explained by this mechanism.

show abstract

Selective oxidation of CO in the presence of H2, H2O and CO2via gold for use in fuel cells

Abstract: An Au/Fe2O3 catalyst prepared using a two-stage calcination procedure achieves target conversion and selectivity for the competitive oxidation of dilute CO in the presence of moist excess H2 and CO2.

Cited by 159 publications

References 18 publications

Heterogeneous catalysts—discovery and design

Heterogeneous catalysts—discovery and design

On the mechanism of selective CO oxidation on nanosized Auγ-Al2O3 catalysts

Dynamic Characterization of the Intermediates for Low-Temperature PROX Reaction of CO in H₂—Oxidation of CO with OH via HCOO Intermediate

Contact Info

Product

Resources

About

Selective oxidation of CO in the presence of H2, H2O and CO2via gold for use in fuel cells

Abstract: An Au/Fe2O3 catalyst prepared using a two-stage calcination procedure achieves target conversion and selectivity for the competitive oxidation of dilute CO in the presence of moist excess H2 and CO2.

Cited by 159 publications

References 18 publications

Heterogeneous catalysts—discovery and design

Heterogeneous catalysts—discovery and design

On the mechanism of selective CO oxidation on nanosized Auγ-Al2O3 catalysts

Dynamic Characterization of the Intermediates for Low-Temperature PROX Reaction of CO in H2—Oxidation of CO with OH via HCOO Intermediate

Contact Info

Product

Resources

About

Dynamic Characterization of the Intermediates for Low-Temperature PROX Reaction of CO in H₂—Oxidation of CO with OH via HCOO Intermediate