Quasi-MOF: Exposing Inorganic Nodes to Guest Metal Nanoparticles for Drastically Enhanced Catalytic Activity

Tsumori, Nobuko; Chen, Liyu; Wang, Qiuju; Zhu, Qi‐Long; Kitta, Mitsunori; Xu, Qiang

doi:10.1016/j.chempr.2018.03.009

Cited by 200 publications

(129 citation statements)

References 48 publications

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“…Due to the strong oxidation ability of Ce, the surface of the original structure is rough and overlapped with the loaded Ce, which will affect the observation of Ce. Through Figure 5c, there are still some carbon skeletons and a large number of Cr elements, which is consistent with the previously reported literature [47]. Figure 5d shows that Ce is mainly dispersed in the framework, which is attributed to the preparation of the double solvent method [57].…”

Section: Characteristics Of the Catalystssupporting

confidence: 89%

“…The original Cr-O bond disappearance may be due to the addition of Ce, which increases the oxidation performance of the catalyst. At the same temperature, partial deligandation phenomenon is aggravated, and the Cr-O bond is converted into Cr 2 O 3 [47]. This is consistent with the XRD characterization.…”

Section: Characteristics Of the Catalystssupporting

confidence: 86%

“…XRD patterns of the quasi-MIL-101(Cr) and CeO 2 /quasi-MIL-101 catalysts with various amounts of deposited ceria being displayed in Figure 2. The quasi-MIL-101(Cr), broadening of the diffractions around 3-10 • from MIL-101(Cr), is observed, which implies the partial deligandation of MIL-101(Cr) and carbon generation [47]. Due to the less Ce content, the XRD diffraction peak is not obvious [52,54].…”

Section: Characteristics Of the Catalystsmentioning

confidence: 95%

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Preparation of Quasi-MIL-101(Cr) Loaded Ceria Catalysts for the Selective Catalytic Reduction of NOx at Low Temperature

Hou

Wei

et al. 2020

Catalysts

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At present, the development of novel catalysts with high activity Selective Catalytic Reduction (SCR) reaction at the low temperature is still a challenge. In this work, the authors prepare CeO2/quasi-MIL-101 catalysts with various amounts of deposited ceria by a double-solvent method, which are characterized by X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and so on. The results show that the increase of Ce content has a great influence on the catalytic property of the catalyst. The introduction of Ce can promote the conversion between Cr3+ and Cr5+ and increase the proportion of lattice oxygen, which improves the activity of the catalyst. However, the catalyst will be peroxidized when the content of Ce is too high, resulting in the decline of the catalytic activity. This experiment indicates that CeO2/quasi-MIL-101 plays a significant role in the NH3-SCR process at the low temperature when the loading of Ce is 0.5%. This work has proved the potential of this kind of material in NH3-SCR process at the low temperature, providing help for subsequent studies.

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Section: Characteristics Of the Catalystssupporting

confidence: 89%

Section: Characteristics Of the Catalystssupporting

confidence: 86%

Section: Characteristics Of the Catalystsmentioning

confidence: 95%

See 1 more Smart Citation

Preparation of Quasi-MIL-101(Cr) Loaded Ceria Catalysts for the Selective Catalytic Reduction of NOx at Low Temperature

Hou

Wei

et al. 2020

Catalysts

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“…The difficulty of using MOFs as templates for nanocasting lies in controlling the process such that casting occurs exclusively inside of the internal void space instead of aggregation on the external surface of the crystal . In this report, we demonstrate that metallic Pt structures can be effectively casted into zirconium‐based MOFs by a two‐step infiltration/reduction process.…”

Section: Methodsmentioning

confidence: 88%

Casting Nanoporous Platinum in Metal–Organic Frameworks

et al. 2019

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Traditionally, porous silica, [10,11] lyotropic liquid crystals, [12,13] and nanospheres assemblies [14,15] have been employed in this process. However, the amorphous backbones of these materials intrinsically inhibit the design of structures with molecular accuracy, and the casted phases are limited to low surface areas. More structurally defined crystalline zeolites have been shown to function as templates for casting highly porous carbon with controlled structures; [16,17] however, introducing metals or metal oxides into zeolites generally leads to the formation of isolated particles instead of extended porous networks. [18,19] As such, developing effective templates for casting nanoporous materials with tunable and controllable structures remains a significant challenge. Metal-organic frameworks (MOFs) are a class of nanoporous crystalline materials with well-defined structures and high surface areas. [20][21][22] MOFs are ideally suited as templates for nanocasting process because of their high porosities, accessible interconnected pore structures, and crystalline backbones. Due to the modular construction based on the discrete polynuclear inorganic clusters (secondary building units, SBUs) and organic linkers, the structure type (topology) and metrics of MOFs can be tailored to achieve the desired pore size and surface area. [23,24] While syntheses of nanoporous carbon [25] and metal oxides [26,27] within MOF templates have been reported, in both cases the replica phases show ill-defined structures with poor ordering. More recently, it was reported that ultrathin, well-aligned metallic nanowires can be uniformly casted into zirconium-based MOF-545, [28] where the MOF's 1D channels are critical for confining the growth of the nanowires. However, casting ordered and porous 3D nanostructures in MOFs still remains an outstanding challenge.The difficulty of using MOFs as templates for nanocasting lies in controlling the process such that casting occurs exclusively inside of the internal void space instead of aggregation on the external surface of the crystal. [29][30][31][32] In this report, we demonstrate that metallic Pt structures can be effectively casted into zirconium-based MOFs by a two-step infiltration/reduction process. Upon removal of the MOF template, nanoporous Pt networks (NP-Pt) with periodic order and high internal surface areas are obtained. We show that the key to avoiding Nanocasting based on porous templates is a powerful strategy in accessing materials and structures that are difficult to form by bottom-up syntheses in a controlled fashion. A facile synthetic strategy for casting ordered, nanoporous platinum (NP-Pt) networks with a high degree of control by using metalorganic frameworks (MOFs) as templates is reported here. The Pt precursor is first infiltrated into zirconium-based MOFs and subsequently transformed to 3D metallic networks via a chemical reduction process. It is demonstrated that the dimensions and topologies of the cast NP-Pt networks can be accurately controlled by using di...

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“…Although bimetallic MOFs materials were attempted as precursors to fabricate bimetallic oxides,23–26 it is very difficult to control composition and structure of two metallic sites because there exist large differences in the radius and chemical coordination behavior of metal ions with organic ligands 27,28. To overcome these problems, introduction of functional species after framework synthesis, i.e., the post‐synthetic modification, may provide a useful tool for obtaining highly sophisticated functionalized structures 29,30. Compared with the direct derivation, this method can improve the controllability of composites and structure and thus offers good opportunity for secondary metallic sites to highly disperse into the MOFs porous matrix.…”

Section: Introductionmentioning

confidence: 99%

Confined Transformation of Organometal‐Encapsulated MOFs into Spinel CoFe₂O₄/C Nanocubes for Low‐Temperature Catalytic Oxidation

Qin

Zheng

et al. 2020

Adv Funct Materials

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Development of spinel bimetallic oxides as low‐cost and high‐efficiency catalysts for catalytic oxidation is highly desired. However, rational design of spinel oxides with controlled structure and components still remains a challenge. A general route for large‐scale preparation of spinel CoFe2O4/C nanocubes transformed from organometal‐encapsulated metal–organic frameworks (MOFs) via exchange–coordination and pyrolysis combined method is reported. Strong confinement effect between organometallics and MOFs realizes reconstruction of crystal phase and composition, but not simple metallic oxides support by Co2+ introduction. Compared with Co3O4‐Fe2O3/C, MOFs‐derived cubic nano‐CoFe2O4/C with higher surface area (115.7 m2 g−1) and favorable surface chemistry exhibits excellent catalytic activity (100% CO conversion at 105 °C) and competitive water‐resisting stability (total conversion at 145 °C for 20 h). Turnover frequency of CoFe2O4/C reaches 4.26 × 10−4 s−1 at 90 °C, two orders of magnitude higher than commercial Co3O4 . Theoretical models show that oxygen vacancies (17.7%) at exposed {112} facet on the carbon interface take superiority in nanocubic spinel phase, which allows reactive species to be strongly adsorbed on nanostructured catalysts' surface and plays key roles in hindering deactivation under moisture rich conditions. The progresses offer a promising way in the development of novel spinel oxides with tailored architecture and properties for vast applications.

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Quasi-MOF: Exposing Inorganic Nodes to Guest Metal Nanoparticles for Drastically Enhanced Catalytic Activity

Abstract: Quasi-MOFs'' realize both an open-framework structure and a strong interaction with the guest metal nanoparticles (NPs). Through controlled deligandation of metal-NP/MOF composites, metal-NP/quasi-MOF composites can be fabricated, leading to dramatically enhanced catalytic performance.

Cited by 200 publications

References 48 publications

Preparation of Quasi-MIL-101(Cr) Loaded Ceria Catalysts for the Selective Catalytic Reduction of NOx at Low Temperature

Preparation of Quasi-MIL-101(Cr) Loaded Ceria Catalysts for the Selective Catalytic Reduction of NOx at Low Temperature

Casting Nanoporous Platinum in Metal–Organic Frameworks

Confined Transformation of Organometal‐Encapsulated MOFs into Spinel CoFe₂O₄/C Nanocubes for Low‐Temperature Catalytic Oxidation

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Quasi-MOF: Exposing Inorganic Nodes to Guest Metal Nanoparticles for Drastically Enhanced Catalytic Activity

Abstract: Quasi-MOFs'' realize both an open-framework structure and a strong interaction with the guest metal nanoparticles (NPs). Through controlled deligandation of metal-NP/MOF composites, metal-NP/quasi-MOF composites can be fabricated, leading to dramatically enhanced catalytic performance.

Cited by 200 publications

References 48 publications

Preparation of Quasi-MIL-101(Cr) Loaded Ceria Catalysts for the Selective Catalytic Reduction of NOx at Low Temperature

Preparation of Quasi-MIL-101(Cr) Loaded Ceria Catalysts for the Selective Catalytic Reduction of NOx at Low Temperature

Casting Nanoporous Platinum in Metal–Organic Frameworks

Confined Transformation of Organometal‐Encapsulated MOFs into Spinel CoFe2O4/C Nanocubes for Low‐Temperature Catalytic Oxidation

Contact Info

Product

Resources

About

Confined Transformation of Organometal‐Encapsulated MOFs into Spinel CoFe₂O₄/C Nanocubes for Low‐Temperature Catalytic Oxidation