Evidences of Two‐Regimes in the Measurement of Ru Particle Size Effect for CO Dissociation during Fischer–Tropsch Synthesis

González-Carballo, Juan M.; Pérez‐Alonso, Francisco J.; Ojeda, Manuel; García-García, Francisco J.; Fierro, J.L.G.; Rojas, Sergio

doi:10.1002/cctc.201402080

Cited by 20 publications

(19 citation statements)

References 75 publications

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“…This mechanism is similar to the well‐accepted mechanism of N 2 dissociation on step‐edge sites of Ru nanoparticles relevant to NH 3 synthesis . However, whether these coordinatively unsaturated sites are active during the FT reaction has been questioned, as they are vulnerable to poisoning by strongly adsorbed CO or reaction intermediates . H‐assisted CO dissociation on terrace sites is therefore considered as an alternative pathway in which CO is hydrogenated to HCO or HCOH intermediates prior to C−O bond cleavage.…”

Section: Figurementioning

confidence: 65%

“…[4] However,w hether these coordinatively unsaturated sites are active during the FT reaction has been questioned, as they are vulnerable to poisoning by strongly adsorbed CO or reactioni ntermediates. [5] H-assisted CO dissociation on terrace sites is therefore considered as an alternative pathway in which CO is hydrogenated to HCO [6] or HCOH [7] intermediates prior to CÀOb ond cleavage. This CO dissociation pathway hasb een invoked in mechanisms that take place on highly CO-covered terraces.…”

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confidence: 99%

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Mechanism of Carbon Monoxide Dissociation on a Cobalt Fischer–Tropsch Catalyst

et al. 2017

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The way in which the triple bond in CO dissociates, a key reaction step in the Fischer–Tropsch (FT) reaction, is a subject of intense debate. Direct CO dissociation on a Co catalyst was probed by 12C16O/13C18O scrambling in the absence and presence of H2. The initial scrambling rate without H2 was significantly higher than the rate of CO consumption under CO hydrogenation conditions, which indicated that the surface contained sites sufficiently reactive to dissociate CO without the assistance of H atoms. Only a small fraction of the surface was involved in CO scrambling. The minor influence of CO scrambling and CO residence time on the partial pressure of H2 showed that CO dissociation was not affected by the presence of H2. The positive H2 reaction order was correlated to the fact that the hydrogenation of adsorbed C and O atoms was slower than CO dissociation. Temperature‐programmed in situ IR spectroscopy underpinned the conclusion that CO dissociation does not require H atoms.

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Section: Figurementioning

confidence: 65%

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confidence: 99%

Mechanism of Carbon Monoxide Dissociation on a Cobalt Fischer–Tropsch Catalyst

et al. 2017

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“…[ 151‐153,159 ] Such size dependence of TOFs over Ru‐catalyzed F‐T synthesis resembles that of Co catalysts in trend, which will be discussed in the following section, [ 160‐162 ] demonstrating a certain similarity between Ru and Co catalysts for F‐T synthesis. The size effect was ascribed to either the geometric effect, i.e ., the fraction of Rh HCSs terrace sites which were considered as the active sites for CO activation, [ 152‐153 ] or the electronic effect and/or support effect. [ 153‐154 ]…”

Section: Particle Size Effect In Metal Catalysismentioning

confidence: 97%

“…[ 149‐158 ] In Ru catalyzed F‐T synthesis, extensive results demonstrated a general trend that the TOFs of CO conversion increased with Ru particle size and became almost constant after reaching the maximum, although the critical Ru particle size might be slightly different. [ 151‐153,159 ] Such size dependence of TOFs over Ru‐catalyzed F‐T synthesis resembles that of Co catalysts in trend, which will be discussed in the following section, [ 160‐162 ] demonstrating a certain similarity between Ru and Co catalysts for F‐T synthesis. The size effect was ascribed to either the geometric effect, i.e ., the fraction of Rh HCSs terrace sites which were considered as the active sites for CO activation, [ 152‐153 ] or the electronic effect and/or support effect.…”

Section: Particle Size Effect In Metal Catalysismentioning

confidence: 99%

A Review on Particle Size Effect in Metal‐Catalyzed Heterogeneous Reactions

Wang

2020

Chin. J. Chem.

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Size of metal nanoparticles (NPs) plays decisive roles in metal-catalyzed heterogeneous reactions, due to the drastic variation of the geometric and electronic properties of metal NPs with size. Along with the development of controlled catalyst synthesis, tremendous efforts have been devoted to understanding the nature of the particle size effect. In particular, identification of the individual roles of size-dependent geometric and electronic effects on metal-catalyzed reactions is essential, but remains challenging since they are tightly hybridized together with particle size variation. In this review, we first discuss the fundamentals of the size-dependent geometric and electronic properties of metal NPs and their crucial roles in catalysis in general. Then we summarize the previous representative studies of the particle size effect, metal-by-metal, in heterogeneous catalysis. We highlighted the extension of particle size effect to ultrafine cluster and single-atom catalysts, the new frontiers in heterogeneous catalysis. In the followings, we further introduce the recent advances in disentangling the size-dependent geometric and electronic effects and unveiling their individual contributions to catalysis. Finally, we discuss the challenges and perspectives of investigations on the size effect in metal catalysis for the future studies. Mr. Hengwei Wang (left) received his B.Sc. degree from School of Chemistry and Materials Science, University of Science and Technology of China (USTC) in 2015. Then he Joined Professor Junling Lu's research group at USTC to pursue his doctorate in Physical Chemistry. His research focuses on atomically-precise design and synthesis of metal nanocatalysts for heterogeneous catalysis and unravelling their structure-reactivity relations at atomic scale. Prof. Junling Lu (right) received his Ph.D. degree from Institute of Physics, Chinese Academy of Sciences under the supervision of Prof. Hong-Jun Gao in 2007. During his Ph.D. studies, he visited Prof. Hans-Joachim Freund's group at Chemical Physics Department, Fritz-Haber-Institute, Max Planck Society as an exchange student in 2004-2006. After graduation, he spent three years in Prof. Peter C Stair's group at Northwestern University and then about two and a half years in Dr. Jeffrey W. Elam's group at Argonne National Laboratory as a Postdoc. In March 2013, he joined USTC as a Professor. His current research interest is atomically-precise design of a new generation of advanced catalysts through a combined wet-chemistry and atomic layer deposition (ALD) approach.

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“…9,10 Besides, they are capable of operating in the presence of large amounts of water. 9,10 The presence of water, whether indigenous or co-fed, can lead to a significant increase in the reaction rate of FTS over Ru-based catalysts with decreasing CH 4 selectivity and increasing C 5+ selectivity. 10 Ru is a nonplasmonic metal.…”

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confidence: 99%

Photocatalytic Fischer–Tropsch Synthesis on Graphene-Supported Worm-Like Ruthenium Nanostructures

et al. 2015

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Fischer−Tropsch synthesis (FTS) converts carbon monoxide and hydrogen to liquid fuels and chemicals and is usually operated under high temperature ranges, which results in an evident increase of energy consumption and CO 2 emission. A photocatalytic FTS route was proposed to efficiently harvest solar energy. Worm-like ruthenium nanostructures dispersed on graphene sheets can effectively catalyze FTS at mild conditions (150°C, 2.0 MPa H 2 , and 1.0 MPa CO) under irradiation of visible light and achieve a catalytic activity as high as 14.4 mol CO ·mol Ru −1 ·h −1 . The reaction rate of FTS can be enhanced by increasing the irradiation intensity or decreasing the irradiation wavelength. The work provides a green and efficient photocatalytic route for FTS. F ischer−Tropsch synthesis (FTS), which converts carbon monoxide and hydrogen (syngas) to hydrocarbons, is an important process to produce liquid fuels and chemicals. 1−3 Traditional FTS employs coal-based syngas as the feedstock, and thus, it is hard to compete with the petroleum industry. With the increasing shortage of global fossil resources, the source of syngas has become diversified, including coal, natural gas, biomass, among others. 4−6 Meanwhile, the price of crude oil has also stayed at a high level. Therefore, FTS has gathered attention again for its ability to produce liquid fuels and chemicals from nonfossil resources. As syngas can be easily produced by biomass resource now, it would be a significant breakthrough if FTS could harvest sunlightthe most abundant energy source on the Earth.Industrial FTS catalysts are usually based upon iron or cobalt conducting under high temperatures (310−340°C for Fe catalysts or 210−260°C for Co catalysts). 7 The high temperature leads to not only high energy consumption but also increased CO 2 emission due to the water−gas shift reaction. 8 Compared to Fe and Co, Ru catalysts are somewhat expensive, but they exhibit higher intrinsic activity, higher stability, and higher selectivity to long-chain hydrocarbons. 9,10 Besides, they are capable of operating in the presence of large amounts of water. 9,10 The presence of water, whether indigenous or co-fed, can lead to a significant increase in the reaction rate of FTS over Ru-based catalysts with decreasing CH 4 selectivity and increasing C 5+ selectivity. 10 Ru is a nonplasmonic metal. Although it does not own the characteristic of so-called surface plasmon resonance, 11,12 its nanoparticles can also significantly absorb UV and visible light. 13,14 The light absorption of metal nanoparticles is generally attributed to the interband transition of bound electrons. Individual bound electrons gain the energy of incident photons and become "hot" electrons with high energy via the interband transition. These light-excited hot electrons in nanoparticles can facilitate chemical transformations of molecules adsorbed on the nanoparticles. 15−17 Recently, we found that graphene can stabilize some metastable nanoparticles, such as Cu 2 O and Cu, and enable them to exhibit stable ...

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Evidences of Two‐Regimes in the Measurement of Ru Particle Size Effect for CO Dissociation during Fischer–Tropsch Synthesis

Cited by 20 publications

References 75 publications

Mechanism of Carbon Monoxide Dissociation on a Cobalt Fischer–Tropsch Catalyst

Mechanism of Carbon Monoxide Dissociation on a Cobalt Fischer–Tropsch Catalyst

A Review on Particle Size Effect in Metal‐Catalyzed Heterogeneous Reactions

Photocatalytic Fischer–Tropsch Synthesis on Graphene-Supported Worm-Like Ruthenium Nanostructures

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