Water–gas shift on gold catalysts: catalyst systems and fundamental studies

Tao, Franklin Feng; Ma, Zhen

doi:10.1039/c3cp51326b

Cited by 67 publications

(47 citation statements)

References 164 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is generally acknowledged that surface of metal particles adsorbs CO and oxygen vacancies of reducible oxides dissociate H 2 O molecules to form OH groups [11,14]. As a reducible oxide support typically provides sites for dissociation of H 2 O molecules, exploration of WGS on other oxidebased catalysts could provide insights to develop different WGS catalysts with high activity at a low temperature.…”

mentioning

confidence: 99%

Water–Gas Shift on Pd/α-MnO2 and Pt/α-MnO2

et al. 2015

View full text Add to dashboard Cite

Low temperature water-gas shift (WGS) catalysts, Pd nanoparticles supported on a-MnO 2 nanorods termed Pd/a-MnO 2 and Pt nanoparticles supported on aMnO 2 nanorods termed Pt/a-MnO 2 were synthesized by introducing Pd or Pt precursor to well-prepared a-MnO 2 nanorods through precipitation deposition with a following annealing at 300°C. They are quite active for WGS in the temperature range of 140-350°C. Activation energies for WGS on Pd/a-MnO 2 and Pt/a-MnO 2 are 45.3 and 56.4 kJ/mol respectively, comparable to precious metal supported on CeO 2 and TiO 2 for WGS. Surface chemistries of the two catalysts during WGS were tracked with ambient pressure X-ray photoelectron spectroscopy. Different from the preservation of the surface and bulk phase of other oxide support such as CeO 2 , TiO 2 in CeO 2 -or TiO 2 -based WGS catalysts, both surface and bulk of aMnO 2 nanorods of Pd/a-MnO 2 and Pt/a-MnO 2 are transited to MnO during WGS. In-situ studies identified oxygen vacancies of the formed MnO support during WGS and the metallic state of Pd and Pt nanoparticles supported on the nonstoichiometric MnO. Graphical Abstract

show abstract

mentioning

confidence: 99%

Water–Gas Shift on Pd/α-MnO2 and Pt/α-MnO2

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Currently, the WGS processes applied in industry mainly include high-temperature WGS processes using commercial FeO x -CrO x catalysts and low-temperature WGS processes using Cu/ZnO/Al 2 O 3 catalysts [2]. However, these commercially available WGS catalysts are usually inadequate for specific applications in PEMFC, due to several universal drawbacks, e.g., low catalytic efficiency, relatively high operation temperature, as well as strict pretreatment procedures and their pyrophoric nature [3]. Hence, continuous efforts have been focused on exploring new and more promising catalysts for the WGS reaction.…”

Section: Introductionmentioning

confidence: 99%

Morphology-Dependent Properties of Cu/CeO2 Catalysts for the Water-Gas Shift Reaction

Ren

Peng

et al. 2017

Catalysts

View full text Add to dashboard Cite

CeO 2 nanooctahedrons, nanorods, and nanocubes were prepared by the hydrothermal method and were then used as supports of Cu-based catalysts for the water-gas shift (WGS) reaction. The chemical and physical properties of these catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption/desorption, UV-Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H 2 -TPR) and in situ diffuse reflectance infra-red fourier transform spectroscopy (DRIFTS) techniques. Characterization results indicate that the morphology of the CeO 2 supports, originating from the selective exposure of different crystal planes, has a distinct impact on the dispersion of Cu and the catalytic properties. The nanooctahedron CeO 2 catalyst (Cu-CeO 2 -O) showed the best dispersion of Cu, the largest amount of moderate copper oxide, and the strongest Cu-support interaction. Consequently, the Cu-CeO 2 -O catalyst exhibited the highest CO conversion at the temperature range of 150-250 • C when compared with the nanocube and nanorod Cu-CeO 2 catalysts. The optimized Cu content of the Cu-CeO 2 -O catalysts is 10 wt % and the CO conversion reaches 91.3% at 300 • C. A distinctive profile assigned to the evolution of different types of carbonate species was observed in the 1000-1800 cm −1 region of the in situ DRIFTS spectra and a particular type of carbonate species was identified as a potential key reaction intermediate at low temperature.

show abstract

“…For instance, semiconductor particles smaller than ∼10 nm act as quantum dots (1-4) and oxide-supported gold nanoparticles are active for a variety of reactions including CO oxidation (5), water-gas-shift reaction (6), and epoxidation (7), whereas gold itself is not. Nanoclusters composed of ∼10 atoms have been shown to be exceptionally catalytically active for some reactions on some metals (8,9).…”

mentioning

confidence: 99%

Influence of support morphology on the bonding of molecules to nanoparticles

Yim

Pang

Hermoso

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Supported metal nanoparticles form the basis of heterogeneous catalysts. Above a certain nanoparticle size, it is generally assumed that adsorbates bond in an identical fashion as on a semiinfinite crystal. This assumption has allowed the database on metal single crystals accumulated over the past 40 years to be used to model heterogeneous catalysts. Using a surface science approach to CO adsorption on supported Pd nanoparticles, we show that this assumption may be flawed. Near-edge X-ray absorption fine structure measurements, isolated to one nanoparticle, show that CO bonds upright on the nanoparticle top facets as expected from single-crystal data. However, the CO lateral registry differs from the single crystal. Our calculations indicate that this is caused by the strain on the nanoparticle, induced by carpet growth across the substrate step edges. This strain also weakens the COmetal bond, which will reduce the energy barrier for catalytic reactions, including CO oxidation.nanoparticle | carpet growth | surface strain | adsorption | scanning tunneling microscopy N anoparticles exhibit properties distinct from their bulk counterparts (1-3). For instance, semiconductor particles smaller than ∼10 nm act as quantum dots (1-4) and oxide-supported gold nanoparticles are active for a variety of reactions including CO oxidation (5), water-gas-shift reaction (6), and epoxidation (7), whereas gold itself is not. Nanoclusters composed of ∼10 atoms have been shown to be exceptionally catalytically active for some reactions on some metals (8, 9). When the particle size is reduced, the relative number of undercoordinated atoms at the edges and corners increases. The proportion of perimeter sites at the interface between the metal and the support also increases. All these sites have been shown to play a crucial role in some reactions (10, 11). Reducing the particle size can also lead to a decrease in the interatomic bond length in small metal clusters (12, 13), which in the case of Pd nanoparticles results in lower adsorption energies for both CO (14,15) and O 2 (16), although such weakening of CO binding on the nanoparticle can also arise from other factors such as encapsulation of the nanoparticles by the support (17).The role of the support in modifying nanoparticle properties has also been recognized. For instance, the strong metal support interaction has been known for some time (2) and charge transfer either to or from the nanoparticles can lead to enhanced reactivity (18). More recently, it has come to light that the particle size itself may be governed by the interaction with the support (19). However, one effect that has not been discussed and yet should be present in any nanoparticle-support system is the influence of the support morphology such as steps.Here, we investigate the role of the support morphology on the reactivity of metal nanoparticles using scanning tunneling microscopy (STM). As our test system we choose Pd nanoparticles (20, 21) supported on TiO 2 (110) (22) simply because much is known about bo...

show abstract

Water–gas shift on gold catalysts: catalyst systems and fundamental studies

Cited by 67 publications

References 164 publications

Water–Gas Shift on Pd/α-MnO2 and Pt/α-MnO2

Water–Gas Shift on Pd/α-MnO2 and Pt/α-MnO2

Morphology-Dependent Properties of Cu/CeO2 Catalysts for the Water-Gas Shift Reaction

Influence of support morphology on the bonding of molecules to nanoparticles

Contact Info

Product

Resources

About