Nanoparticles as Recyclable Catalysts: The Frontier Between Homogeneous and Heterogeneous Catalysis

Astruc, Didier; Lu, Feng; Aranzaes, Jaime Ruiz

doi:10.1002/chin.200609261

Cited by 233 publications

(300 citation statements)

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“…The awaruite grains observed here are nanosized (Fig. 3C) and, therefore, have a high surface area-to-volume ratio, which should enhance their catalytic activity (51). Thus, nanosized alloys could have facilitated CH 4 production over geologically relevant timescales below the upper temperature limit for life (122°C).…”

Section: ) Indicate Thatmentioning

confidence: 82%

Subduction zone forearc serpentinites as incubators for deep microbial life

Plümper

Geisler

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Serpentinization-fueled systems in the cool, hydrated forearc mantle of subduction zones may provide an environment that supports deep chemolithoautotrophic life. Here, we examine serpentinite clasts expelled from mud volcanoes above the Izu-BoninMariana subduction zone forearc (Pacific Ocean) that contain complex organic matter and nanosized Ni-Fe alloys. Using time-of-flight secondary ion mass spectrometry and Raman spectroscopy, we determined that the organic matter consists of a mixture of aliphatic and aromatic compounds and functional groups such as amides. Although an abiotic or subduction slab-derived fluid origin cannot be excluded, the similarities between the molecular signatures identified in the clasts and those of bacteria-derived biopolymers from other serpentinizing systems hint at the possibility of deep microbial life within the forearc. To test this hypothesis, we coupled the currently known temperature limit for life, 122°C, with a heat conduction model that predicts a potential depth limit for life within the forearc at ∼10,000 m below the seafloor. This is deeper than the 122°C isotherm in known oceanic serpentinizing regions and an order of magnitude deeper than the downhole temperature at the serpentinized Atlantis Massif oceanic core complex, MidAtlantic Ridge. We suggest that the organic-rich serpentinites may be indicators for microbial life deep within or below the mud volcano. Thus, the hydrated forearc mantle may represent one of Earth's largest hidden microbial ecosystems. These types of protected ecosystems may have allowed the deep biosphere to thrive, despite violent phases during Earth's history such as the late heavy bombardment and global mass extinctions.deep biosphere | serpentinization | subduction zone | forearc

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Section: ) Indicate Thatmentioning

confidence: 82%

Subduction zone forearc serpentinites as incubators for deep microbial life

Plümper

Geisler

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Many nanoparticles have been used to catalyze a variety of chemical reactions. In many cases, nanoparticles are loaded on the surface of solid supports to form heterogeneous catalysts since this facilitates catalyst recovery [5]. In addition, in several cases, the strong synergistic interaction between nanoparticles and solid supports can greatly enhance the catalytic activity and selectivity [6,7].…”

Section: Introductionmentioning

confidence: 99%

In situ loading of Cu2O nanoparticles on a hydroxyl group rich TiO2 precursor as an excellent catalyst for the Ullmann reaction

2010

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An in situ method has been used to load Cu 2 O nanoparticles on the surface of a hydroxyl group rich TiO 2 precursor. Cu 2 O nanoparticles are formed by in situ reduction of Cu(OH) 2 with Sn 2+ ions linked to the surface of the TiO 2 precursor. The initial Cu 2 O nanoparticles serve as seeds for subsequent particle growth. The resulting Cu 2 O nanoparticles are evenly dispersed on the surface of the TiO 2 precursor, and are heat and air stable. The as-prepared composite is an excellent catalyst for Ullmann type cross coupling reactions of aryl halides with phenol. The composite catalyst also showed good stability, remaining highly active after five consecutive runs.

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“…Commonly used procedures include Pt 4? or Pt 2? salts reduction by borohydride [12][13][14][15][16], hydrogen [17,18], alcohol [19][20][21][22][23][24], glycol [25,26], or ethylene glycol [27,28] in the presence of a stabilizer or on a solid support. Despite a large choice of synthetic protocols, an accurate control of the particle size, simple and reproducible synthetic strategies are important to investigate their physical and chemical properties.…”

Section: Introductionmentioning

confidence: 99%

Optimized reduction conditions for the microfluidic synthesis of 1.3 ± 0.3 nm Pt clusters

et al. 2015

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Recently, small (\2 nm) and monodispersed Pt clusters has gained much attention due to their high catalytic activity in the aerobic oxidations. However, the chemical synthesis of small Pt clusters is not trivial; high temperature is often required to completely reduce the Pt 4?/2? ions to Pt 0 , which accelerates the growth of the Pt clusters. Here, we discussed a very simple microfluidic reduction of Pt 4? to Pt 0 by NaBH 4 in the presence of PVP that produces \2 nm Pt clusters in any variable reduction conditions. The microfluidic reduction conditions were optimized for the synthesis of possible smallest Pt clusters in terms of five reaction parameters: (1) temperature, (2) concentration of H 2 PtCl 6 , (3) molar ratio of NaBH 4 to Pt 4? ions, (4) molar ratio of PVP-monomer to Pt 4? ions, and (5) molecular weight/chain length of PVP. We found that possible smallest particles with average diameter 1.3 ± 0.3 nm were produced when aqueous solutions of H 2 PtCl 6 (4 mM) and NaBH 4 (40 mM) containing PVP (160 mM) were injected into the micromixer placed in an icebath at a flow rate of 200 mL/h. The produced particles were characterized by UV-visible absorption spectrophotometry, powder X-ray diffractometry and transmission electron microscopy.

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Nanoparticles as Recyclable Catalysts: The Frontier Between Homogeneous and Heterogeneous Catalysis

Abstract: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Cited by 233 publications

References 1 publication

Subduction zone forearc serpentinites as incubators for deep microbial life

Subduction zone forearc serpentinites as incubators for deep microbial life

In situ loading of Cu2O nanoparticles on a hydroxyl group rich TiO2 precursor as an excellent catalyst for the Ullmann reaction

Optimized reduction conditions for the microfluidic synthesis of 1.3 ± 0.3 nm Pt clusters

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