Mechanism for the water–gas shift reaction on monofunctional platinum and cause of catalyst deactivation

Flaherty, David W.; Yu, Wen‐Yueh; Pozun, Zachary D.; Henkelman, Graeme; Mullins, C. Buddie

doi:10.1016/j.jcat.2011.06.024

Cited by 64 publications

(93 citation statements)

References 83 publications

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“…Since the dissociation of water on Ni(111) is not fast, the WGS cannot compete with the Boudouard reaction and eventually the surface is deactivated by the formation of a carbon layer. A similar problem has been reported for the WGS on Pt(111) 23. In the case of Ni/CeO 2 (111), the presence of Ni 2+ sites not only favors the dissociation of OH bonds but also makes more difficult the cleavage of CO bonds 8.…”

supporting

confidence: 70%

In Situ and Theoretical Studies for the Dissociation of Water on an Active Ni/CeO₂ Catalyst: Importance of Strong Metal–Support Interactions for the Cleavage of O–H Bonds

et al. 2015

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Water dissociation is crucial in many catalytic reactions on oxide-supported transition-metal catalysts. Supported by experimental and density-functional theory results, the effect of the support on OH bond cleavage activity is elucidated for nickel/ceria systems. Ambient-pressure O 1s photoemission spectra at low Ni loadings on CeO2 (111) reveal a substantially larger amount of OH groups as compared to the bare support. Computed activation energy barriers for water dissociation show an enhanced reactivity of Ni adatoms on CeO2 (111) compared with pyramidal Ni4 particles with one Ni atom not in contact with the support, and extended Ni(111) surfaces. At the origin of this support effect is the ability of ceria to stabilize oxidized Ni(2+) species by accommodating electrons in localized f-states. The fast dissociation of water on Ni/CeO2 has a dramatic effect on the activity and stability of this system as a catalyst for the water-gas shift and ethanol steam reforming reactions.

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confidence: 70%

In Situ and Theoretical Studies for the Dissociation of Water on an Active Ni/CeO₂ Catalyst: Importance of Strong Metal–Support Interactions for the Cleavage of O–H Bonds

et al. 2015

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“…7. These TOFs are much larger than the values found in previous studies for the WGS reaction on benchmark surfaces such as Cu(111) or Pt(111) [23,24], where the TOFs are always smaller than 1 molecule/metal site sec.…”

Section: Catalytic Activity Of Au/ceo X /Tio 2 (110) For the Water-gacontrasting

confidence: 70%

Water–gas shift reaction over gold nanoparticles dispersed on nanostructured CeOx–TiO2(110) surfaces: Effects of high ceria coverage

et al. 2016

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Scanning tunnelling microscopy has been used to study the morphology of an overlayer of ceria in contact with a TiO 2 (110) substrate. Two types of domains were observed after ceria deposition. An ordered ceria film covered half of the surface and high-resolution imaging suggested a near-c(6 × 2) relationship to the underlying TiO 2 (110)-(1 × 1). The other half of the surface comprised CeO x nanoparticles and reconstructed TiO x supported on TiO 2 (110)-(1 × 1). Exposure to a small amount of gold resulted in the formation of isolated gold atoms and small clusters on the ordered ceria film and TiO 2 (110)-(1 × 1) areas, which exhibited significant sintering at 500 K and showed strong interaction between the sintered gold clusters and the domain boundaries of the ceria film. The Au/CeO x /TiO 2 (110) model system proved to be a good catalyst for the water-gas shift (WGS) exhibiting much higher turnover frequencies (TOFs) than Cu(111) and Pt(111) benchmarks, or the individual Au/TiO 2 (110) and Au/CeO 2 (111) systems. For Au/CeO x /TiO 2 (110) catalysts, there was a decrease in catalytic activity with increasing ceria coverage that correlates with a reduction in the concentration of Ce 3+ formed during WGS reaction conditions.Published by Elsevier B.V.

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“…Several reasons for this deactivation could be enumerated. Firstly, the formation of carbonaceous deposits over the Ni based catalysts through CO dissociation via Boudouard reaction, previously reported by Flaherty et al [37] and Wu et al [38]. However the presence of copper, in principle, should mitigate this deactivation.…”

Section: Stability Of the Catalystmentioning

confidence: 91%

Mono and bimetallic Cu-Ni structured catalysts for the water gas shift reaction

Arbeláez

Reina

Ivanova

et al. 2015

Applied Catalysis A: General

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Highlights-Efficient Cu-Ni catalysts supported on activated carbon for the water gas shift reaction.-Supressed methanation activity due to the presence of Cu.-Cu-Ni alloy as a key factor of the catalytic design.-Good stability and tolerance towards start/stop situations. AbstractThe water-gas shift (WGS) reaction over structured Cu, Ni, and bimetallic Cu-Ni supported on active carbon (AC) catalysts was investigated. The structured catalysts were prepared in pellets form and applied in the medium range WGS reaction. A good activity in the 180-350 °C temperature range was registered being the bimetallic Cu-Ni:2-1/AC catalyst the best catalyst. Page 2 of 38A c c e p t e d M a n u s c r i p tThe presence of Cu mitigates the methanation activity of Ni favoring the shift process. In addition the active carbon gasification reaction was not observed for the Cu-containing catalyst converting the active carbon in a very convenient support for the WGS reaction. The stability of the bimetallic Cu-Ni:2-1/AC catalyst under continuous operation conditions, as well as its tolerance towards start/stop cycles was also evaluated.

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Mechanism for the water–gas shift reaction on monofunctional platinum and cause of catalyst deactivation

Cited by 64 publications

References 83 publications

In Situ and Theoretical Studies for the Dissociation of Water on an Active Ni/CeO₂ Catalyst: Importance of Strong Metal–Support Interactions for the Cleavage of O–H Bonds

In Situ and Theoretical Studies for the Dissociation of Water on an Active Ni/CeO₂ Catalyst: Importance of Strong Metal–Support Interactions for the Cleavage of O–H Bonds

Water–gas shift reaction over gold nanoparticles dispersed on nanostructured CeOx–TiO2(110) surfaces: Effects of high ceria coverage

Mono and bimetallic Cu-Ni structured catalysts for the water gas shift reaction

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Mechanism for the water–gas shift reaction on monofunctional platinum and cause of catalyst deactivation

Cited by 64 publications

References 83 publications

In Situ and Theoretical Studies for the Dissociation of Water on an Active Ni/CeO2 Catalyst: Importance of Strong Metal–Support Interactions for the Cleavage of O–H Bonds

In Situ and Theoretical Studies for the Dissociation of Water on an Active Ni/CeO2 Catalyst: Importance of Strong Metal–Support Interactions for the Cleavage of O–H Bonds

Water–gas shift reaction over gold nanoparticles dispersed on nanostructured CeOx–TiO2(110) surfaces: Effects of high ceria coverage

Mono and bimetallic Cu-Ni structured catalysts for the water gas shift reaction

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Product

Resources

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In Situ and Theoretical Studies for the Dissociation of Water on an Active Ni/CeO₂ Catalyst: Importance of Strong Metal–Support Interactions for the Cleavage of O–H Bonds

In Situ and Theoretical Studies for the Dissociation of Water on an Active Ni/CeO₂ Catalyst: Importance of Strong Metal–Support Interactions for the Cleavage of O–H Bonds