Aggregation-Based Crystal Growth and Microstructure Development in Natural Iron Oxyhydroxide Biomineralization Products

Banfield, Jillian F.; Welch, Susan A.; Zhang, Hengzhong; Ebert, Tamara Thomsen; Penn, R. Lee

doi:10.1126/science.289.5480.751

Cited by 1,669 publications

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“…In the classical models,can also play an important role in the growth process [13][14][15][16][17]. For instance, oriented attachment was proposed as a growth mechanism to account for the formation of aggregates, nanorods, or nanowires for various metals and metal oxides [18][19][20][21][22][23]. Using in situ transmission electron microscopy (TEM), Alivisatos and co-workers recently provided direct evidence for the involvement of particle coalescence in the growth of Pt nanocrystals [24].…”

Section: Introductionmentioning

confidence: 99%

New insights into the growth mechanism and surface structure of palladium nanocrystals

et al. 2010

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This paper presents a systematic study of the growth mechanism for Pd nanobars synthesized by reducing Na 2 PdCl 4 with L-ascorbic acid in an aqueous solution in the presence of bromide ions as a capping agent. Transmission electron microscopy (TEM) and high-resolution TEM analyses revealed that the growth at early stages of the synthesis was dominated by particle coalescence, followed by shape focusing via recrystallization and further growth via atomic addition. We also investigated the detailed surface structure of the nanobars using aberration-corrected scanning TEM and found that the exposed {100} surfaces contained several types of defects such as an adatom island, a vacancy pit, and atomic steps. Upon thermal annealing, the nanobars evolved into a more thermodynamically favored shape with enhanced truncation at the corners. KEYWORDSPalladium, nanocrystals, growth, coalescence, surface evolution Metal nanocrystals have attracted growing attention due to their fascinating properties and invaluable applications in catalysis, photonics, sensing, and imaging [1][2][3]. The physicochemical properties of a metal nanocrystal are determined by a set of parameters such as shape, size, and composition. In particular, shape control of a metal nanocrystal can provide a versatile avenue for tailoring its catalytic activity and selectivity because shape determines the arrangements of atoms on the surface [4][5][6][7][8]. For example, it has been shown that Pd nanocubes bounded by {100} facets can provide a four-fold improvement in specific activity for the formic acid oxidation reaction as compared to Pd octahedra bounded by {111} facets [9]. An exquisite shape control of metal nanocrystals is therefore essential for the maximization of their activity and thus their performance in many catalytic and electrocatalytic applications.In order to achieve a high-level control over the shape of metal nanocrystals prepared in a solution phase, a fundamental understanding of nucleation and growth mechanisms is a prerequisite. In the classical models, nanocrystals have been considered to grow by atomic addition [10][11][12]. However, recent experimental and theoretical studies have shown that particle coalescence Nano Res (2010) 3: 180-188 DOI 10.1007/s12274-010-1021-5 Research Article † These two authors contributed equally to this work.Address correspondence to Younan Xia, xia@biomed.wustl.edu; Jingyue Liu, liuj@umsl.edu Nano Res (2010) 3: 180-188 181 can also play an important role in the growth process [13][14][15][16][17]. For instance, oriented attachment was proposed as a growth mechanism to account for the formation of aggregates, nanorods, or nanowires for various metals and metal oxides [18][19][20][21][22][23]. Using in situ transmission electron microscopy (TEM), Alivisatos and co-workers recently provided direct evidence for the involvement of particle coalescence in the growth of Pt nanocrystals [24]. Despite these studies, however, a detailed description of the growth process is still missing, especially for...

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Section: Introductionmentioning

confidence: 99%

New insights into the growth mechanism and surface structure of palladium nanocrystals

et al. 2010

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“…These nanoparticle-based materials provide a unique challenge in assessing structure-property relationships because of the disordered arrangement of nanocrystals that results when nanoparticles collide and aggregate [2][3][4][5][6] . The morphological evolution that follows aggregation further obscures the influence of particle size, shape, and interfacial characteristics in defining the physical properties of these materials 7,8 .…”

Section: Use Policymentioning

confidence: 99%

Identifying champion nanostructures for solar water-splitting

et al. 2013

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Citation for published item:rrenD FgF nd o¤ %t hovskyD uF nd hot nD rF nd veroyD gFwF nd gornuzD wF nd tell iD pF nd r¡ e ertD gF nd oths hildD eF nd qr¤ tzelD wF @PHIQA 9sdentifying h mpion n nostru tures for sol r w terEsplittingF9D x ture m teri lsFD IP @WAF ppF VRPEVRWF Further information on publisher's website: httpXGGdxFdoiForgGIHFIHQVGnm tQTVR Publisher's copyright statement: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Charge transport in nanoparticle-based materials underlies many emerging energy conversion technologies, yet assessing the impact of nanometer-scale structure on charge transport across micron-scale distances remains a challenge. Here we develop an approach for correlating the spatial distribution of crystalline and current-carrying domains in entire nanoparticle aggregates. We apply this approach to nanoparticle-based α-Fe 2 O 3 electrodes that are of interest in solar-to-hydrogen energy conversion. In correlating structure and charge transport with nanometer resolution across micron-scale distances, we have identified the existence of champion nanoparticle aggregates that are most responsible for the high photoelectrochemical activity of the present electrodes. Indeed, when electrodes are fabricated with a high proportion of these champion nanostructures, the electrodes achieve the highest photocurrent of any metal oxide photoanode for photoelectrochemical water splitting under 100 mW cm -2 air mass 1.5 global sunlight.Batteries, fuel cells, and solar energy conversion devices have emerged as a class of important technologies that increasingly rely upon electrodes derived from nanoparticles 1 . These nanoparticle-based materials provide a unique challenge in assessing structure-property relationships because of the disordered arrangement of nanocrystals that results when nanoparticles collide and aggregate [2][3][4][5][6] . The morphological evolution that follows aggregation further obscures the influence of particle size, shape, and interfacial characteristics in defining the physical properties of these materials 7,8 . For the nanoparticle-based electrodes used in solar energy conversion, structural defects such as grain boundaries define pathways for charge transport by creating potential barriers and by promoting recombination 9 . Because of the complexity of these materials, within a single electrode there may exist a small proportion of "champion" nanostructures-by analogy with champion solar cells 10,11 , these are nanostructures that provide the highest solar conversion efficiencies-th...

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“…This recrystallization process has not been observed in cave systems where microbial Mn deposits have ages of 1 Ma (Rossi et al, 2010), however, and the reason for these discrepancies remains unresolved within the literature at this time. It is possible that the growth of the highly ordered crystals in these ores formed via an oriented attachment mechanism using available Mn oxide microcrystals produced on cell or EPS surfaces as nucleation sites (Banfield et al, 2000;Fang et al, 2011;Smythe, 2015). This latter coupled biotic/abiotic crystallization mechanism is consistent with the presence of radiating crystals which increase in size from the nucleation sites ( Figures 7E, 8) and have a high degree of crystallinity.…”

Section: Mountain City Windowmentioning

confidence: 99%

New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA

Carmichael

Doctor

Wilson

et al. 2017

Geological Society of America Bulletin

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Manganese oxide deposits have long been observed in association with carbonates within the Appalachian Mountains, but their origin has remained enigmatic for well over a century. Ore deposits of Mn oxides from several productive sites located in eastern Tennessee and northern Virginia display morphologies that include botryoidal and branching forms, massive nodules, breccia matrix cements, and fracture fills. The primary ore minerals include hollandite, cryptomelane, and romanèchite. Samples of Mn oxides from multiple localities in these regions were analyzed using electron microscopy, X-ray analysis, Fourier transform infrared spectroscopy, and trace/rare earth element geochemistry. The samples from eastern Tennessee have biological morphologies, contain residual biopolymers, and exhibit REE signatures that suggest the ore formation was due to supergene enrichment (likely coupled with microbial activity). In contrast, several northern Virginia ores hosted within quartz-sandstone breccias exhibit petrographic relations, mineral morphologies, and REE signatures indicating inorganic precipitation, and a likely hydrothermal origin with supergene overprinting. Nodular accumulations of Mn oxides within weathered alluvial deposits that occur near to breccia-hosted Mn deposits in Virginia show geochemical signatures that are distinct from the breccia matrices, and appear to reflect remobilization of earlier-emplaced Mn and concentration within supergene traps. Based on the proximity of all of the productive ore deposits to mapped faults or other zones of deformation, we suggest that the primary source of all of the Mn may have been deep-seated, and that Mn oxides with supergene and/or biological characteristics result from the local remobilization and concentration of this primary Mn. Carmichael ABSTRACTManganese oxide deposits have long been observed in association with carbonates within the Appalachian Mountains, but their origin has remained enigmatic for well over a century. Ore deposits of Mn oxides from several productive sites located in eastern Tennessee and northern Virginia display morphologies that include botryoidal and branching forms, massive nodules, breccia matrix cements, and fracture fills. The primary ore minerals include hollandite, cryptomelane, and romanèchite. Samples of Mn oxides from multiple localities in these regions were analyzed using electron microscopy, X-ray analysis, Fourier transform infrared spectroscopy, and trace/rare earth element geochemistry. The samples from eastern Tennessee have biological morphologies, contain residual biopolymers, and exhibit REE signatures that suggest the ore formation was due to supergene enrichment (likely coupled with microbial activity). In contrast, several northern Virginia ores hosted within quartz-sandstone breccias exhibit petrographic relations, mineral morphologies, and REE signatures indicating inorganic precipitation, and a likely hydrothermal origin with supergene overprinting. Nodular accumulations of Mn oxides within weathered al...

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Aggregation-Based Crystal Growth and Microstructure Development in Natural Iron Oxyhydroxide Biomineralization Products

Cited by 1,669 publications

References 16 publications

New insights into the growth mechanism and surface structure of palladium nanocrystals

New insights into the growth mechanism and surface structure of palladium nanocrystals

Identifying champion nanostructures for solar water-splitting

New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA

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