One-step solution-based catalytic route to fabricate novel α-MnO<sub>2</sub>hierarchical structures on a large scale

Li, Zhengquan; Ding, Yue; Xiong, Yujie; Yang, Qing; Xie, Yi

doi:10.1039/b414204g

Cited by 184 publications

(125 citation statements)

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“…[ 2 ] Because of the strong size/morphologyproperty correlation upheld by nanotechnology, coupled with their (OMS-2 materials) current wide-ranging embryonic applications in gas cleansing, separation, batteries, catalysis, and chemical sensing, [3][4][5][6][7] a fair amount of attention has recently been paid towards tailoring their crystal system, particle size, and morphology. To realize this, a considerable number of strategies including manipulation of temperature, pressure, time, and pH under hydrothermal [8][9][10] and refl ux [ 11 ] conditions, as well as the use of co-solvents, [ 11 ] sols, [12][13][14] catalysts, [ 15 ] and reducing agents [ 16 , 17 ] have been explored.…”

Section: Introductionmentioning

confidence: 99%

Manganese Oxide Octahedral Molecular Sieves (OMS-2) Multiple Framework Substitutions: A New Route to OMS-2 Particle Size and Morphology Control

et al. 2010

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Self-assembled multidoped cryptomelane hollow microspheres with ultrafi ne particles in the size range of 4-6 nm, and with a very high surface area of 380 m 2 g − 1 have been synthesized. The particle size, morphology, and the surface area of these materials are readily controlled via multiple framework substitutions. The X-ray diffraction and transmission electron microscopy (TEM) results indicate that the as-synthesized multidoped OMS-2 materials are pristine and crystalline, with no segregated metal oxide impurities. These results are corroborated by infrared (IR) and Raman spectroscopy data, which show no segregated amorphous and/or crystalline metal impurities. The fi eld-emission scanning electron microscopy (FESEM) studies confi rm the homogeneous morphology consisting of microspheres that are hollow and constructed by the self-assembly of pseudo-fl akes, whereas energy-dispersive X-ray (EDX) analyses imply that all four metal cations are incorporated into the OMS-2 structure. On the other hand, thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC) demonstrate that the as-synthesized multidoped OMS-2 hollow microspheres are more thermally unstable than their single-doped and undoped counterparts. However, the in-situ XRD studies show that the cryptomelane phase of the multidoped OMS-2 hollow microspheres is stable up to about 450 ° C in air. The catalytic activity of these microspheres towards the oxidation of diphenylmethanol is excellent compared to that of undoped OMS-2 materials.

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Section: Introductionmentioning

confidence: 99%

Manganese Oxide Octahedral Molecular Sieves (OMS-2) Multiple Framework Substitutions: A New Route to OMS-2 Particle Size and Morphology Control

et al. 2010

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“…A solution-based catalytic route was promoted to synthesize a new type of hierarchical structure of a-MnO 2 , a core-shell structure with spherically aligned nanorods, by Xie and co-workers. [15] The chemical, electrical, catalytic, and magnetic properties of manganese dioxides depend strongly on their crystallographic structures and architectures. The 3D architectures often produce more active sites or exhibit more interesting electrical, optical, and magnetic properties than the 2D or 1D architectures.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal Growth of Manganese Dioxide into Three‐Dimensional Hierarchical Nanoarchitectures

Ding

Shen

Gómez

et al. 2006

Adv Funct Materials

197

134

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Novel three‐dimensional (3D) hierarchical nanoarchitectures of ϵ‐MnO2 have been synthesized by a simple chemical route without the addition of any surfactants or organic templates. The self‐organized crystals consist of a major ϵ‐MnO2 dipyramidal single crystal axis and six secondary branches, which are arrays of single‐crystal ϵ‐MnO2 nanobelts. The growth directions of the nanobelts are perpendicular to the central dipyramidal axis, which shows sixfold symmetry. The shape of the ϵ‐MnO2 assembly can be controlled by the reaction temperature. The morphology of ϵ‐MnO2 changes from a six‐branched star‐like shape to a hexagonal dipyramidal morphology when the temperature is increased from 160 to 180 °C. A possible growth mechanism is proposed. The synthesized ϵ‐MnO2 shows both semiconducting and magnetic properties. These materials exhibit ferromagnetic behavior below 25 K and paramagnetic behavior above 25 K. The ϵ‐MnO2 system may have potential applications in areas such as fabrication of nanoscale spintronic materials, catalysis, and sensors.

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“…Recently, SiO 2 particles have attracted much interest in catalysis, catalysis supports, 26 drug delivery, 27 etc. In this paper, we selected the typical pollen grains, namely, camellia pollen, rape pollen, and sweet potato pollen as templates to fabricate morphology-controlled SiO 2 replicas in a simple surface sol-gel and succedent calcination process.…”

Section: Introductionmentioning

confidence: 99%

Morphology‐controlled Synthesis of SiO₂ Hierarchical Structures Using Pollen Grains as Templates

Guan¹,

Zhang²,

Lu³

et al. 2008

Chin. J. Chem.

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Rape-, sweet potato-and camellia-pollen-templated SiO 2 hierarchical structures with species-specific surface morphologies were prepared through a facile surface sol-gel and succedent calcination process. Various-morphology SiO 2 replicas with complex structures, such as about 50-µm-length and 20-µm-width high-fidelity ellipsoidal replicas with about 5-µm uniform meshes, about 40-µm spheres with 2-µm taper-like protuberances and 15-µm spheres with troughs, were obtained from using rape-, sweet potato-and camellia pollen grains as templates, respectively. The results of N 2 adsorption-desorption isotherms indicate that both rape-and camellia-pollentemplated SiO 2 replicas show type IV-like isotherm with the characteristics of mesoporosity and corresponding Brunauer-Emmett-Teller (BET) surface areas are 10.5 and 5.2 m 2 •g -1 , respectively. The Barrett-Joyner-Halenda (BJH) pore size distribution of the rape-pollen-templated SiO 2 replicas presents smaller pores centered at 3.6 nm and bigger pores centered at 8.6 nm with a broad distribution whereas the camelliapollen-templated SiO 2 replicas display narrow BJH pore size distribution centered at 20 nm. The biofabrication procedure using ubiquitous, inexpensive and environment-friendly pollen grains as a biotemplate holds a promise as a simple route to construct controlled complex porous oxides via simple chemical methods.

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One-step solution-based catalytic route to fabricate novel α-MnO₂hierarchical structures on a large scale

Abstract: A new type of hierarchical structure, a core-shell structure with spherically aligned nanorods, was prepared via a simple room-temperature solution-based catalytic route in the case of alpha-MnO2.

Cited by 184 publications

References 19 publications

Manganese Oxide Octahedral Molecular Sieves (OMS-2) Multiple Framework Substitutions: A New Route to OMS-2 Particle Size and Morphology Control

Manganese Oxide Octahedral Molecular Sieves (OMS-2) Multiple Framework Substitutions: A New Route to OMS-2 Particle Size and Morphology Control

Hydrothermal Growth of Manganese Dioxide into Three‐Dimensional Hierarchical Nanoarchitectures

Morphology‐controlled Synthesis of SiO₂ Hierarchical Structures Using Pollen Grains as Templates

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One-step solution-based catalytic route to fabricate novel α-MnO2hierarchical structures on a large scale

Abstract: A new type of hierarchical structure, a core-shell structure with spherically aligned nanorods, was prepared via a simple room-temperature solution-based catalytic route in the case of alpha-MnO2.

Cited by 184 publications

References 19 publications

Manganese Oxide Octahedral Molecular Sieves (OMS-2) Multiple Framework Substitutions: A New Route to OMS-2 Particle Size and Morphology Control

Manganese Oxide Octahedral Molecular Sieves (OMS-2) Multiple Framework Substitutions: A New Route to OMS-2 Particle Size and Morphology Control

Hydrothermal Growth of Manganese Dioxide into Three‐Dimensional Hierarchical Nanoarchitectures

Morphology‐controlled Synthesis of SiO2 Hierarchical Structures Using Pollen Grains as Templates

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One-step solution-based catalytic route to fabricate novel α-MnO₂hierarchical structures on a large scale

Morphology‐controlled Synthesis of SiO₂ Hierarchical Structures Using Pollen Grains as Templates