Single-atom active sites on metal-organic frameworks

Ranocchiari, Marco; Lothschütz, Christian; Grolimund, Daniel; Bokhoven, Jeroen A. van

doi:10.1098/rspa.2012.0078

Cited by 54 publications

(40 citation statements)

References 69 publications

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“…In addition, ion‐exchanged metals supported on porous materials, as well as organometallic complexes anchored to supports, in principle, could also be viewed as SACs 1c. 7 The concept of SAC is novel and the catalysts are totally different from conventional heterogeneous catalysts, which consist of various metal nanostructures and supports with huge specific areas. SACs have high activities and enable the utmost utilization of supported metals, and they also provide single active sites, which offers superior selectivity as homogeneous catalysts 1a.…”

Section: Concept Synthesis and Key Issuesmentioning

confidence: 99%

The Power of Single‐Atom Catalysis

2015

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Single‐atom catalysts (SACs) with individual and isolated metal atoms anchored to supports can act as active centers. Single‐atom catalysis is powerful and attractive because SACs have demonstrated distinguishing performances, such as drastic cost‐reduction, notable catalytic activity, and selectivity. Herein, we firstly introduce SAC, including the concept and some key issues in synthesis and catalysis. Then, the power of single‐atom catalysis is highlighted and the most recent advances are summarized. It is very encouraging that in recent years our understanding of SACs has increased, owing to substantial studies regarding sample preparation, characterization, evaluation, and also mechanistic interpretation. On the other hand, great challenges still remain for SACs.

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Section: Concept Synthesis and Key Issuesmentioning

confidence: 99%

The Power of Single‐Atom Catalysis

2015

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“…The enhanced catalytic activity of clusters of a few nanometers or less is a result of enhanced contact area, low coordination sites and electronic confinement effects 43. 44 Single‐atom catalysis has now become a reality, and the field has gained more attention over the past year 45–48. For example, single‐atom catalysis by atomically dispersed Pt on iron oxide shows a significantly high CO oxidation rate 45.…”

Section: Introductionmentioning

confidence: 99%

Rh₁/γ‐Al₂O₃ Single‐Atom Catalysis of O₂ Activation and CO Oxidation: Mechanism, Effects of Hydration, Oxidation State, and Cluster Size

2013

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The single‐atom catalysis of O2 activation and CO oxidation with Rh1 supported on γ‐Al2O3 is investigated here through ab initio molecular dynamics techniques. We scrutinize the molecular details of the mechanism for the full catalytic cycle that involves the oxidation of two CO molecules in succession. The effect of the surface hydration and oxidation state of Rh on the kinetics of O2 activation and CO oxidation is presented. We also report here the catalytic activity of experimentally intercepted RhI(CO)2 on γ‐Al2O3. Furthermore, we delineate the importance of single‐atom catalysis by comparing the performance of the Rh6/Al2O3 catalyst. A molecular level understanding of the differential reactivity on hydration, on oxidation, and of a larger Rh cluster size is reported.

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“…Ion-exchanged metals supported on porous materials such as metalÀorganic frameworks (MOFs) and zeolites, as well as organometallic complexes anchored to supports, in principle could also be viewed as SACs. 17,20,21 In this Account, we will focus on investigations of single metal atoms anchored to metal oxides, metal surfaces, and graphene.…”

Section: Introductionmentioning

confidence: 99%

Single-Atom Catalysts: A New Frontier in Heterogeneous Catalysis

et al. 2013

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Supported metal nanostructures are the most widely used type of heterogeneous catalyst in industrial processes. The size of metal particles is a key factor in determining the performance of such catalysts. In particular, because low-coordinated metal atoms often function as the catalytically active sites, the specific activity per metal atom usually increases with decreasing size of the metal particles. However, the surface free energy of metals increases significantly with decreasing particle size, promoting aggregation of small clusters. Using an appropriate support material that strongly interacts with the metal species prevents this aggregation, creating stable, finely dispersed metal clusters with a high catalytic activity, an approach industry has used for a long time. Nevertheless, practical supported metal catalysts are inhomogeneous and usually consist of a mixture of sizes from nanoparticles to subnanometer clusters. Such heterogeneity not only reduces the metal atom efficiency but also frequently leads to undesired side reactions. It also makes it extremely difficult, if not impossible, to uniquely identify and control the active sites of interest.The ultimate small-size limit for metal particles is the single-atom catalyst (SAC), which contains isolated metal atoms singly dispersed on supports. SACs maximize the efficiency of metal atom use, which is particularly important for supported noble metal catalysts. Moreover, with well-defined and uniform single-atom dispersion, SACs offer great potential for achieving high activity and selectivity.In this Account, we highlight recent advances in preparation, characterization, and catalytic performance of SACs, with a focus on single atoms anchored to metal oxides, metal surfaces, and graphene. We discuss experimental and theoretical studies for a variety of reactions, including oxidation, water gas shift, and hydrogenation. We describe advances in understanding the spatial arrangements and electronic properties of single atoms, as well as their interactions with the support. Single metal atoms on support surfaces provide a unique opportunity to tune active sites and optimize the activity, selectivity, and stability of heterogeneous catalysts, offering the potential for applications in a variety of industrial chemical reactions.

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Single-atom active sites on metal-organic frameworks

Cited by 54 publications

References 69 publications

The Power of Single‐Atom Catalysis

The Power of Single‐Atom Catalysis

Rh₁/γ‐Al₂O₃ Single‐Atom Catalysis of O₂ Activation and CO Oxidation: Mechanism, Effects of Hydration, Oxidation State, and Cluster Size

Single-Atom Catalysts: A New Frontier in Heterogeneous Catalysis

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Single-atom active sites on metal-organic frameworks

Cited by 54 publications

References 69 publications

The Power of Single‐Atom Catalysis

The Power of Single‐Atom Catalysis

Rh1/γ‐Al2O3 Single‐Atom Catalysis of O2 Activation and CO Oxidation: Mechanism, Effects of Hydration, Oxidation State, and Cluster Size

Single-Atom Catalysts: A New Frontier in Heterogeneous Catalysis

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Rh₁/γ‐Al₂O₃ Single‐Atom Catalysis of O₂ Activation and CO Oxidation: Mechanism, Effects of Hydration, Oxidation State, and Cluster Size