The redispersion of sintered Pt, Rh, and Pt/Rh catalysts

D'Aniello, M. J.; Monroe, David R.; Carr, Constance J.; Krueger, Martin H.

doi:10.1016/0021-9517(88)90223-0

Cited by 31 publications

(10 citation statements)

References 23 publications

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“…The information on reactivation of spent NMscontaining catalysts used in HPR is limited compared with some advancements made in reactivation of spent conventional HPR catalysts. 11 In the study conducted by D'Aniello et al, 206 the spent monometallic Pt and Rh as well as bimetallic Pt-Rh all supported on γ-Al 2 O 3 were used to test the chlorination method for catalyst reactivation. The method was based on the treatment with chlorine, chlorine + air, and bromine.…”

Section: Energy and Fuelsmentioning

confidence: 99%

“…For these experiments, fresh catalysts were thermally aged at 800 °C for 4 h to induce particles aggregation. 206 The characterization of fresh and corresponding aged catalysts by TEM revealed the particle sizes of 2−5 and 25−30 nm, respectively. In the case of Pt/Al 2 O 3 catalyst, after re-dispersion in chlorine, the size of particles was less than 2 nm.…”

Section: Energy and Fuelsmentioning

confidence: 99%

“…In the study conducted by D’Aniello et al, the spent monometallic Pt and Rh as well as bimetallic Pt-Rh all supported on γ-Al 2 O 3 were used to test the chlorination method for catalyst reactivation. The method was based on the treatment with chlorine, chlorine + air, and bromine.…”

Section: Regeneration Of Spent Noble Metals-containing Catalystsmentioning

confidence: 99%

“…For these experiments, fresh catalysts were thermally aged at 800 °C for 4 h to induce particles aggregation . The characterization of fresh and corresponding aged catalysts by TEM revealed the particle sizes of 2–5 and 25–30 nm, respectively.…”

Section: Regeneration Of Spent Noble Metals-containing Catalystsmentioning

confidence: 99%

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Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

Marafi

Furimsky²

2017

Energy Fuels

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Interest in the use of catalysts containing noble metals (NMs) in various hydroprocessing (HPR) applications is the result of an increasing volume of unconventional feeds and a continuous change in performance parameters of petroleum products. Conventional HPR catalysts can only partially fulfill new requirements. The high price of NMs and their high activity under both reducing and oxidative atmospheres require some modifications of the strategies that have been used for the handling of spent conventional HPR catalysts. Because of their higher activity, the deactivation of NMs-containing catalysts during HPR occurs under less severe conditions compared with that of conventional HPR catalysts. However, adverse effects of sulfur, nitrogen, oxygenates, and metals in feeds may require a higher severity to achieve HPR objectives. The activity of spent NMscontaining catalysts can be almost completely recovered by regeneration. The oxidative regeneration of spent NMs-containing catalysts has been performed commercially, while reductive and extractive regenerations offer alternative routes. The high value of NMs dictates that metal recovery is the only option if an adequate catalyst activity recovery cannot be achieved by regeneration. The methods are available for NMs recovery on an industrial scale. Also, the research aiming at improvement of metals recovery via existing methods as well as development novel methods has been noted.

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Section: Energy and Fuelsmentioning

confidence: 99%

Section: Energy and Fuelsmentioning

confidence: 99%

Section: Regeneration Of Spent Noble Metals-containing Catalystsmentioning

confidence: 99%

Section: Regeneration Of Spent Noble Metals-containing Catalystsmentioning

confidence: 99%

See 2 more Smart Citations

Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

Marafi

Furimsky²

2017

Energy Fuels

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“…Catalysts consisting of alloyed nanoparticles often provide higher rates or selectivities for desired reactions than respective pure metal catalysts. − Particularly significant examples of industrially relevant alloyed catalysts include PdAg , and PdPb for alkyne semihydrogenation, PtSn for alkane dehydrogenation, PdAu for vinyl acetate monomer synthesis, and PtRh for simultaneous NO x reduction and CO and hydrocarbon oxidation . Differences in catalytic reactivity between monometallic and alloyed nanoparticles are frequently attributed to changes in the electronic structure caused by formation of heteronuclear metallic bonds or differences in the number and identity of reactive metal atoms present in ensembles that form active sites for catalysis.…”

Section: Introductionmentioning

confidence: 99%

Effect of Pd Coordination and Isolation on the Catalytic Reduction of O₂ to H₂O₂ over PdAu Bimetallic Nanoparticles

et al. 2021

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The direct synthesis of hydrogen peroxide (H2 + O2 → H2O2) may enable low-cost H2O2 production and reduce environmental impacts of chemical oxidations. Here, we synthesize a series of Pd1Au x nanoparticles (where 0 ≤ x ≤ 220, ∼10 nm) and show that, in pure water solvent, H2O2 selectivity increases with the Au to Pd ratio and approaches 100% for Pd1Au220. Analysis of in situ XAS and ex situ FTIR of adsorbed 12CO and 13CO show that materials with Au to Pd ratios of ∼40 and greater expose only monomeric Pd species during catalysis and that the average distance between Pd monomers increases with further dilution. Ab initio quantum chemical simulations and experimental rate measurements indicate that both H2O2 and H2O form by reduction of a common OOH* intermediate by proton–electron transfer steps mediated by water molecules over Pd and Pd1Au x nanoparticles. Measured apparent activation enthalpies and calculated activation barriers for H2O2 and H2O formation both increase as Pd is diluted by Au, even beyond the complete loss of Pd–Pd coordination. These effects impact H2O formation more significantly, indicating preferential destabilization of transition states that cleave O–O bonds reflected by increasing H2O2 selectivities (19% on Pd; 95% on PdAu220) but with only a 3-fold reduction in H2O2 formation rates. The data imply that the transition states for H2O2 and H2O formation pathways differ in their coordination to the metal surface, and such differences in site requirements require that we consider second coordination shells during the design of bimetallic catalysts.

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Spreading and Wetting

Knözinger

Taglauer

2008

Handbook of Heterogeneous Catalysis

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The sections in this article are Introduction Theoretical Considerations Thermodynamics of Wetting and Spreading Qualitative Discussion of the Dynamics of Interfacial Processes Supported Metal Catalysts Sintering and Redispersion Strong Metal Support Interactions ( SMSI ) Bimetallic Catalysts Supported Oxide Catalysts Molybdenum‐Based Catalysts Vanadium‐Based Catalysts Tungsten‐Based Catalysts Zeolites as Supports Solid‐State Ion Exchange of Zeolites

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The redispersion of sintered Pt, Rh, and Pt/Rh catalysts

Cited by 31 publications

References 23 publications

Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

Effect of Pd Coordination and Isolation on the Catalytic Reduction of O₂ to H₂O₂ over PdAu Bimetallic Nanoparticles

Spreading and Wetting

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The redispersion of sintered Pt, Rh, and Pt/Rh catalysts

Cited by 31 publications

References 23 publications

Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

Hydroprocessing Catalysts Containing Noble Metals: Deactivation, Regeneration, Metals Reclamation, and Environment and Safety

Effect of Pd Coordination and Isolation on the Catalytic Reduction of O2 to H2O2 over PdAu Bimetallic Nanoparticles

Spreading and Wetting

Contact Info

Product

Resources

About

Effect of Pd Coordination and Isolation on the Catalytic Reduction of O₂ to H₂O₂ over PdAu Bimetallic Nanoparticles