Çalışma öncelikle Ulusal Bilim Vakfı (NSF) tarafından finanse edildi, Kimya Bölümü (Ödülü numarası CHE-1507370) kabul edilmektedir. Ayman M. Karim ve Wenhui Li kabul 3M tarafından kısmi finansal destek sigara Tenured öğretim Ödülü. Bu araştırma kullanılan kaynaklar Gelişmiş foton kaynak (beamline 12-ID-C, Kullanıcı öneri GUP-45774), bir ABD bölümü enerji (DOE) Ofis, bilim Kullanıcı tesis için DOE Office Bilim Sözleşme No altında Argonne Ulusal Laboratuvarı tarafından işletilen DE-AC02-06CH11357. Yazarlar Yubing Lu, SAXS ölçümleri nazik onun yardımıyla Virginia Tech Kimya Mühendisliği bölümünde doktora adayı teşekkür etmek istiyorum. Bir ofis bilim Kullanıcı tesis ABD bölümü enerji (DOE) Office Bilim için ameliyat, sunulan iş kısmen için entegre nanoteknoloji merkezinde idam edildi. Los Alamos Ulusal Laboratuvarı, pozitif ayrımcılık eşit fırsat işveren, Los Alamos Ulusal güvenlik, LLC, ABD Enerji Bakanlığı Sözleşmeli DE-AC52-06NA25396 Ulusal Nükleer güvenlik yönetimi için işletilmektedir.

Raporlanacak hiçbir çıkar çatışması vardır.

Bu çalışmada, ligandlar çekirdekleşme ve metal nano tanecikleri büyüme sınırı etkisini incelemek için güçlü bir metodoloji sunduk. Pd nano tanecikleri farklı çözücüler (Toluen ve pyridine) olarak sentezlenmiş Pd asetat metal habercisi ve üst ligand kullanarak. Azaltılmış atomlar (çekirdekleşme ve büyüme olayları) konsantrasyonu nano tanecikleri (çekirdekleşme olay), konsantrasyon yanı sıra deneysel her iki tane observable modeli girdi kullanıldığı ayıklamak için in situ SAX...

Metalik nano tanecikleri kontrollü sentezi kataliz, fotovoltaik, fotonik, sensörler ve ilaç teslim1,2,3nanostructured malzemelerin büyük uygulamalar nedeniyle büyük önem taşıyor, 4,5. Belirli boyut ve boyut dağılımı ile nano tanecikleri sentezlemek için parçacık çekirdekleşme ve büyüme için temel mekanizmasını anlamak önemlidir. Yine de, nano tanecikleri gibi kriterler ile edinme nano-sentez topluluk sentez mekanizmaları ve sağlam kinetik modelleri literatürde mevcut eksikliği anlamada yavaş ilerleme nedeniyle meydan okudu. 1950'lerde LaMer manken çekirdekleşme ve kükürt süslenmiş, gelişmesi için önerilen çekirdeği6,7difüzyon kontrollü büyüme tarafından takip çekirdekleşme bir patlama olduğu. Önerilen bu modelde bu monomer konsantrasyonu (azaltma veya habercisi ayrışma nedeniyle) arttığını öne ise ve parçacık çekirdekleşme aşmak için düzeyi kritik supersaturation, enerji bariyeri bir kez bir patlama çekirdekleşme (homojen çekirdekleşme) kaynaklanan. Önerilen veri bloğu çekirdekleşme sayesinde, monomer konsantrasyon damla ve kritik supersaturation düzeyin altına düştüğünde, çekirdekleşme durdurur. Daha sonra kurulan çekirdekleri hiçbir ek çekirdekleşme olayları oluşurken monomerleri nano tanecikleri yüzeyden doğru difüzyon yoluyla büyümeye öne. Bu etkili bir şekilde çekirdekleşme ve büyüme zaman ayıran ve boyutu dağıtım8büyüme süreci sırasında denetleme olur. Bu model Ag9, Au10, CdSe11ve Fe3O412de dahil olmak üzere farklı nano tanecikleri oluşumunu açıklamak için kullanılmıştır. Ancak, çeşitli çalışmalarda klasik çekirdekleşme teorisi (CNT) kolloidal nano tanecikleri, oluşumu özellikle nerede çekirdekleşme ve büyüme çakışma1gözlenen metalik nano tanecikleri için tanımlayamayacağım resimli, 13,14,15,16,17. Bu çalışmalar birinde, Watzky ve Finke iridyum nano tanecikleri13yavaş sürekli çekirdekleşme bir hızlı nanopartikül yüzey büyüme (büyüme otokatalitik nerede) ile çakışıyor, oluşumu için bir iki adım mekanizma kurdu. Yavaş çekirdekleşme ve hızlı otokatalitik büyüme de metal nano tanecikleri gibi Pd14,15,18, Pt19,20ve Rh21 farklı türleri için tespit edildi ,22. Gelişmekte olan çekirdekleşme ve büyüme modelleri1,23,24,25, ligandlar rolünün son gelişmeler rağmen sık sık önerilen modellerinde yoksayılır. Yine de, ligandlar nano tanecikleri boyutu14,15,26 ve morfoloji19,27 yanı sıra katalitik aktivitesi ve seçicilik28 etkilemeye gösterilir , 29. Örneğin, Yang ve ark. 30 trioctylphosphine (üst) konsantrasyonu değiştirerek 9,5 ve 15 nm arasında değişen Pd nanopartikül boyutu kontrol. Manyetik Nano tanecikleri (Fe3O4) sentezinde boyutu önemli ölçüde azalmıştır 11'den 5'e ne zaman metal habercisi oranı (octadecylamine) ligand 1 ile 60 arttı nm. İlginçtir, Pt nano tanecikleri boyutunu Amin ligandlar zincir uzunluğu hassas olduğu gösterilmiştir (Örn., n-hexylamine ve octadecylamine), daha küçük nanopartikül boyutu uzun zinciri kullanma elde edilebilir nerede (i.e., octadecylamine)31.
Farklı konsantrasyon ve farklı ligandlar neden boyutu değişiklik ligandlar çekirdekleşme ve büyüme kinetik içinde katkı için açık bir delildir. Ne yazık ki, birkaç çalışmalar rol ligandlar ve bu çalışmalarda sorumluydu, çeşitli varsayımlar kez basitlik uğruna, hangi sırayla bu modeller sadece belirli koşullar32,33için geçerli yapmak yapılmıştır. Daha ayrıntılı olarak, Rempel ve iş ligandlar kapatma huzurunda kuantum nokta (CdSe) oluşumunu açıklamak için kinetik bir model geliştirdi. Ancak, onların çalışmada, denge herhangi bir zamanda32olmak nanopartikül yüzeyli ligand bağlayıcı kabul edilir. Ligandlar büyük fazla olduğunda bu varsayım doğru tutabilir. Bizim grup yakın zamanda ligandlar habercisi (metal karmaşık) ve nanopartikül olarak ters tepkiler14yüzeyi ile kapatma bağlama sorumluydu yeni bir ligand tabanlı modeli14 geliştirdi. Buna ek olarak, bizim ligand tabanlı modeli potansiyel olarak diğer metal nanopartikül sistemlerinde nerede sentez kinetik ligandlar varlığı ile etkilendiğimi kullanılabilir.
Mevcut çalışmada, oluşumu ve Pd nano tanecikleri Toluen ve pyridine de dahil olmak üzere farklı çözücüler içinde büyüme tahmin etmek için bizim yeni geliştirilen ligand tabanlı modeli kullanın. Bizim model girişi için in situ SAXS konsantrasyonu sentezi sırasında nano tanecikleri ve boyut dağılımının elde etmek için kullanılmıştır. Kinetik modelleme tarafından tamamlanmaktadır parçacıklar, konsantrasyon ve boyutu ölçüm çekirdekleşme ve büyüme oranları daha kesin bilgi almak için bize izin verir. Biz daha fazla göstermek açıkça ligand-metal bağlama için hesapları, bizim ligand tabanlı modeli son derece akıllı ve nano tanecikleri istediğiniz boyutları ile elde etmek için sentez yordamlar tasarlamak için kullanılabilir.

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			<td height="21" style="height:21px;width:291px;">anhydrous acetic acid</td>
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			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:291px;">trioctylphosphine</td>
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			<td style="width:119px;">718165</td>
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			<td height="21" style="height:21px;width:291px;">pyridine</td>
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			<td height="21" style="height:21px;width:291px;">1-hexanol</td>
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			<td height="21" style="height:21px;width:291px;">7 mL vials</td>
			<td style="width:203px;">SUPELCO</td>
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			<td height="21" style="height:21px;width:291px;">25 mL round bottom flasks</td>
			<td style="width:203px;">ALDRICH</td>
			<td style="width:119px;">Z167495</td>
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			<td height="21" style="height:21px;width:291px;">quartz capillary</td>
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			<td style="width:119px;">HR6-148</td>
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			<td height="21" style="height:21px;width:291px;">MATLAB R2016b</td>
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			<td height="21" style="height:21px;width:291px;">Bruker SAXS 1.0v</td>
			<td style="width:203px;">Bruker</td>
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</table>

ligand-mediated nucleation and growth of palladium metal nanoparticles

Boyut, boyut dağılımı ve kolloidal nano tanecikleri kararlılığını ligandlar kapatma varlığını tarafından büyük ölçüde etkilenir. Ligandlar sentez reaksiyonu sırasında kapatma anahtar katkı rağmen kolloidal nano tanecikleri çekirdekleşme ve büyüme oranları düzenleyen rollerini iyi anlaşılamamıştır. Bu çalışmada, biz Pd nano tanecikleri içinde farklı çözücüler (Toluen ve pyridine), trioctylphosphine (üst) rolünün mekanik bir soruşturma göstermek in situ SAXS ve kinetik modelleme ligand tabanlı kullanma. Bizim sonuçları farklı sentetik koşullar altında çekirdekleşme örtüşme ve Pd nano tanecikleri büyüme LaMer tipi çekirdekleşme ve büyüme modeli çelişmektedir reaksiyon sırasında ortaya koyuyor. Model Pd-TOP kinetik için bağlayıcı, habercisi hem boyutu evrim gibi parçacıklar içinde in situkonsantrasyonu yakalamak için gerekli olan parçacık yüzey için hesapları. Buna ek olarak, nano tanecikleri istediğiniz boyutları ile elde etmek için sentetik koşullar tasarımı ile bizim ligand tabanlı modeli öngörü gücünü göstermek. Önerilen metodoloji diğer sentez sistemlere uygulanabilir ve bu nedenle akıllı kolloidal nano tanecikleri sentezi için etkili bir strateji olarak hizmet vermektedir.

Sistematik olarak kapatma ligandlar kinetik çekirdekleşme ve büyüme değiştirmek olup olmadığını incelemek için biz iki aşağıdaki yaklaşım aldı: (i) metal ile ligand bağlanması için önceki çalışmalarda benzer kinetik modelindeki düşünülmedi (i.e., çekirdekleşme ve otokatalitik büyüme) (II) ligand habercisi ve nanoparçacık yüzeyi ile kapatma tersinir bağlama modeli dikkate alınmıştır (i.e., iletişim kuralında tanımlanan ligand tab...

Watch this Scientific Journal Video about Ligand-Mediated Nucleation and Growth of Palladium Metal Nanoparticles at JoVE.com

Ligand-Mediated Nucleation and Growth of Palladium Metal Nanoparticles

Çekirdekleşme ligand-aracılı ve Paladyum Metal nano tanecikleri gelişmesi

Bu eser ana birleştirerek benn in situ küçük açı x-ray saçılma (SAXS) ve kinetik modelleme ligand tabanlı Paladyum nano tanecikleri boyutunu düzenlenmesinde ajanlar kapatma rolü aydınlatmak için hedeftir.

The size, size distribution and stability of colloidal nanoparticles are greatly affected by the presence of capping ligands. Despite the key contribution ...

ligand-mediated-nucleation-and-growth-of-palladium-metal-nanoparticles

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10.3K Görüntüleme.  Virginia Polytechnic Institute and State University. Bu eser ana birleştirerek benn in situ küçük açı x-ray saçılma (SAXS) ve kinetik modelleme ligand tabanlı Paladyum nano tanecikleri boyutunu düzenlenmesinde ajanlar kapatma rolü aydınlatmak için hedeftir.

Video: Ligand-Mediated Nucleation and Growth of Palladium Metal Nanoparticles

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

Fonksiyonlu Sentezi ve Karakterizasyonu Metal-organik Altyapıları

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

Kimya

Using Polystyrene-block-poly(acrylic acid)-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are encapsulated in polystyrene-block-poly(acrylic acid) (PSPAA) shells and then used as monomers for their self-assembly. Spherical PSPAA micelles upon acid treatment are known to assemble into cylindrical micelles. Exploiting this tendency, the core-shell nanoparticles are induced to aggregate, coalesce, and then transform into long chains. When more than one type of nanoparticles are used, random and block &#8220;copolymers&#8221; of nanoparticles can be obtained. Detailed procedures are reported for the PSPAA encapsulation of nanoparticles, homo- and co-polymerization of the core-shell nanoparticles, separation and purification of the resulting nanoparticle chains. Transformations of single-line chains into double- and triple-line chains are also presented. The synergy between the polymer shell and the embedded nanoparticles leads to an unusual chain-growth polymerization mode, giving long nanoparticle chains that are distinct from the products of the traditional step-growth aggregation process.

Using Polystyrene-block-polyacrylic acid-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We report protocols for &#8220;polymerizing&#8221; various types of polymer-encapsulated metal nanoparticles into long chains of &#8220;homo-&#8220; and &#8220;co-polymers&#8221;.

Polistiren kullanma<em&gt; Bloğu</em&gt; -poli (Akrilik asit) Bunların homo- ve ko-polimerizasyon için monomer olarak metal Nanopartiküller -kaplı

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are ...

Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The silica-encapsulated metal oxide nanoparticles are then carburized in a methane/hydrogen atmosphere at temperatures over 800 &#176;C to form silica-encapsulated early transition metal carbide nanoparticles. During the carburization process, the silica shells prevent the sintering of adjacent carbide nanoparticles while also preventing the deposition of excess surface carbon. Alternatively, the silica-encapsulated metal oxide nanoparticles can be nitridized in an ammonia atmosphere at temperatures over 800 &#176;C to form silica-encapsulated early transition metal nitride nanoparticles. By adjusting the reverse microemulsion parameters, the thickness of the silica shells, and the carburization/nitridation conditions, the transition metal carbide or nitride nanoparticles can be tuned to various sizes, compositions, and crystal phases. After carburization or nitridation, the silica shells are then removed using either a room-temperature aqueous ammonium bifluoride solution or a 0.1 to 0.5 M NaOH solution at 40-60 &#176;C. While the silica shells are dissolving, a high surface area support, such as carbon black, can be added to these solutions to obtain supported early transition metal carbide or nitride nanoparticles. If no high surface area support is added, then the nanoparticles can be stored as a nanodispersion or centrifuged to obtain a nanopowder.

A &#8220;removable ceramic coating method&#8221; is presented in visual format for the synthesis of non-sintered and metal-terminated monometallic and bimetallic early transition metal carbide and nitride nanoparticles with tunable sizes and crystal structures.

Monometalik ve Bimetalik Erken Geçiş Metal Carbide ve Nitrür Nanopartiküller Ters Mikroemülsiyon aracılı sentezi

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The ...

Generation of Zerovalent Metal Core Nanoparticles Using n-(2-aminoethyl)-3-aminosilanetriol

In this work, a facile one-pot reaction for the formation of metal nanoparticles in a water solution through the use of n-(2-aminoethyl)-3-aminosilanetriol is presented. This compound can be used to effectively reduce and complex metal salts into metal core nanoparticles coated with the compound. By controlling the concentrations of salt and silane one is able to control reaction rates, particle size, and nanoparticle coating. The effects of these changes were characterized through transmission electron microscopy (TEM), UV-Vis spectrometry (UV-Vis), Nuclear Magnetic Resonance spectroscopy (NMR) and Fourier Transform Infrared spectroscopy (FTIR). A unique aspect to this reaction is that usually silanes hydrolyze and cross-link in water; however, in this system the silane is water-soluble and stable. It is known that silicon and amino moieties can form complexes with metal salts. The silicon is known to extend its coordination sphere to form penta- or hexa-coordinated species. Furthermore, the silanol group can undergo hydrolysis to form a Si-O-Si silica network, thereby transforming the metal nanoparticles into a functionalized nanocomposites.

Generation of Zerovalent Metal Core Nanoparticles Using n-2-aminoethyl-3-aminosilanetriol

A novel method for metal core nanoparticle synthesis using a water stable silanol is described.

Sıfır değerlikli metal çekirdek Nanopartiküller Üretimi N- (2-aminoetil) -3-aminosilanetriol

In this work, a facile one-pot reaction for the formation of metal nanoparticles in a water solution through the use of ...

Photochemical Oxidative Growth of Iridium Oxide Nanoparticles on CdSe@CdS Nanorods

We demonstrate a procedure for the photochemical oxidative growth of iridium oxide catalysts on the surface of seeded cadmium selenide-cadmium sulfide (CdSe@CdS) nanorod photocatalysts. Seeded rods are grown using a colloidal hot-injection method and then moved to an aqueous medium by ligand exchange. CdSe@CdS nanorods, an iridium precursor and other salts are mixed and illuminated. The deposition process is initiated by absorption of photons by the semiconductor particle, which results with formation of charge carriers that are used to promote redox reactions. To insure photochemical oxidative growth we used an electron scavenger. The photogenerated holes oxidize the iridium precursor, apparently in a mediated oxidative pathway. This results in the growth of high quality crystalline iridium oxide particles, ranging from 0.5 nm to about 3 nm, along the surface of the rod. Iridium oxide grown on CdSe@CdS heterostructures was studied by a variety of characterization methods, in order to evaluate its characteristics and quality. We explored means for control over particle size, crystallinity, deposition location on the CdS rod, and composition. Illumination time and excitation wavelength were found to be key parameters for such control. The influence of different growth conditions and the characterization of these heterostructures are described alongside a detailed description of their synthesis. Of significance is the fact that the addition of iridium oxide afforded the rods astounding photochemical stability under prolonged illumination in pure water (alleviating the requirement for hole scavengers).

A protocol for the photochemical oxidative growth of small crystalline iridium oxide nanoparticles on the surface of CdSe@CdS seeded rod nanoparticles is presented.

CdSe @ CdS nanorods üzerinde İridyum Oksit Nanopartiküller Fotokimyasal Oksidatif Büyüme

We demonstrate a procedure for the photochemical oxidative growth of iridium oxide catalysts on the surface of seeded cadmium selenide-cadmium sulfide ...

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. They offer new possibilities for the characterization of living systems and are particularly appropriate for detecting, localizing and quantifying the presence of metal oxide nanoparticles both in biological specimens and the environment. Indeed, these techniques all meet relevant requirements in terms of (i) sensitivity (from 1 up to 10 &#181;g.g-1 of dry mass), (ii) micrometer range spatial resolution, and (iii) multi-element detection. Given these characteristics, microbeam chemical element imaging can powerfully complement routine imaging techniques such as optical and fluorescence microscopy. This protocol describes how to perform a nuclear microprobe analysis on cultured cells (U2OS) exposed to titanium dioxide nanoparticles. Cells must grow on and be exposed directly in a specially designed sample holder used on the optical microscope and in the nuclear microprobe analysis stages. Plunge-freeze cryogenic fixation of the samples preserves both the cellular organization and the chemical element distribution. Simultaneous nuclear microprobe analysis (scanning transmission ion microscopy, Rutherford backscattering spectrometry and particle induced X-ray emission) performed on the sample provides information about the cellular density, the local distribution of the chemical elements, as well as the cellular content of nanoparticles. There is a growing need for such analytical tools within biology, especially in the emerging context of Nanotoxicology and Nanomedicine for which our comprehension of the interactions between nanoparticles and biological samples must be deepened. In particular, as nuclear microprobe analysis does not require nanoparticles to be labelled, nanoparticle abundances are quantifiable down to the individual cell level in a cell population, independently of their surface state.

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

We describe a procedure for the detection of chemical elements present in situ in human cells as well as their in vitro quantification. The method is well-suited to any cell type and is particularly useful for quantitative chemical analyses in single cells following in vitro metal oxide nanoparticles exposure.

Situ Algılama ve Metal Oksit nano tanecikleri nükleer Microprobe analizi ile tek hücre miktar

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. ...

High Resolution Physical Characterization of Single Metallic Nanoparticles

Individual molecules can be detected and characterized by measuring the degree by which they reduce the ionic current flowing through a single nanometer-scale pore. The signal is characteristic of the molecule&#39;s physicochemical properties and its interactions with the pore. We demonstrate that the nanopore formed by the bacterial protein exotoxin Staphylococcus aureus alpha hemolysin (&#945;HL) can detect polyoxometalates (POMs, anionic metal oxygen clusters), at the single molecule limit. Moreover, multiple degradation products of 12-phosphotungstic acid POM (PTA, H3PW12O40) in solution are simultaneously measured. The single molecule sensitivity of the nanopore method allows for POMs to be characterized at significantly lower concentrations than required for nuclear magnetic resonance (NMR) spectroscopy. This technique could serve as a new tool for chemists to study the molecular properties of polyoxometalates or other metallic clusters, to better understand POM synthetic processes, and possibly improve their yield. Hypothetically, the location of a given atom, or the rotation of a fragment in the molecule, and the metal oxidation state could be investigated with this method. In addition, this new technique has the advantage of allowing the real-time monitoring of molecules in solution.&#160;

Here, we present a protocol to detect discrete metal oxygen clusters, polyoxometalates (POMs), at the single molecule limit using a biological nanopore-based electronic platform. The method provides a complementary approach to traditional analytical chemistry tools used in the study of these molecules.

Tek metalik nanopartiküller yüksek çözünürlüklü fiziksel karakterizasyonu

Individual molecules can be detected and characterized by measuring the degree by which they reduce the ionic current flowing through a single ...

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. Here, we introduce the molten-salt synthesis (MSS) method for making metal oxide nanomaterials. Advantages over other methods include its simplicity, greenness, reliability, scalability, and generalizability. Using pyrochlore lanthanum hafnium oxide (La2Hf2O7) as a representative, we describe the MSS protocol for the successful synthesis of complex metal oxide nanoparticles (NPs). Furthermore, this method has the unique ability to produce NPs with different material features by changing various synthesis parameters such as pH, temperature, duration, and post-annealing. By fine-tuning these parameters, we are able to synthesize highly uniform, non-agglomerated, and highly crystalline NPs. As a specific example, we vary the particle size of the La2Hf2O7&#160;NPs by changing the concentration of the ammonium hydroxide solution used in the MSS process, which allows us to further explore the effect of particle size on various properties. It is expected that the MSS method will become a more popular synthesis method for nanomaterials and more widely employed in the nanoscience and nanotechnology community in the upcoming years.

Here, we demonstrate a unique, relatively low-temperature, molten-salt synthesis method for preparing uniform complex metal oxide lanthanum hafnate nanoparticles.

Karmaşık Metal Oksit nano tanecikleri erimiş tuz sentezi

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. ...

Synthesis and Characterization of Amphiphilic Gold Nanoparticles

Gold nanoparticles covered with a mixture of 1-octanethiol (OT) and 11-mercapto-1-undecane sulfonic acid (MUS) have been extensively studied because of their interactions with cell membranes, lipid bilayers, and viruses. The hydrophilic ligands make these particles colloidally stable in aqueous solutions and the combination with hydrophobic ligands creates an amphiphilic particle that can be loaded with hydrophobic drugs, fuse with the lipid membranes, and resist nonspecific protein adsorption. Many of these properties depend on nanoparticle size and the composition of the ligand shell. It is, therefore, crucial to have a reproducible synthetic method and reliable characterization techniques that allow the determination of nanoparticle properties and the ligand shell composition. Here, a one-phase chemical reduction, followed by a thorough purification to synthesize these nanoparticles with diameters below 5 nm, is presented. The ratio between the two ligands on the surface of the nanoparticle can be tuned through their stoichiometric ratio used during synthesis. We demonstrate how various routine techniques, such as transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), and ultraviolet-visible (UV-Vis) spectrometry, are combined to comprehensively characterize the physicochemical parameters of the nanoparticles.

Amphiphilic gold nanoparticles can be used in many biological applications. A protocol to synthesize gold nanoparticles coated by a binary mixture of ligands and a detailed characterization of these particles is presented.

Amphiphilik altın nanopartiküller sentezi ve karakterizasyonu

Gold nanoparticles covered with a mixture of 1-octanethiol (OT) and 11-mercapto-1-undecane sulfonic acid (MUS) have been extensively studied because of ...

Synthesis Method for Cellulose Nanofiber Biotemplated Palladium Composite Aerogels

Here, a method to synthesize cellulose nanofiber biotemplated palladium composite aerogels is presented. Noble metal aerogel synthesis methods often result in fragile aerogels with poor shape control. The use of carboxymethylated cellulose nanofibers (CNFs) to form a covalently bonded hydrogel allows for the reduction of metal ions such as palladium on the CNFs with control over both nanostructure and macroscopic aerogel monolith shape after supercritical drying. Crosslinking the carboxymethylated cellulose nanofibers is achieved using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) in the presence of ethylenediamine. The CNF hydrogels maintain their shape throughout synthesis steps including covalent crosslinking, equilibration with precursor ions, metal reduction with high concentration reducing agent, rinsing in water, ethanol solvent exchange, and CO2 supercritical drying. Varying the precursor palladium ion concentration allows for control over the metal content in the final aerogel composite through a direct ion chemical reduction rather than relying on the relatively slow coalescence of pre-formed nanoparticles used in other sol-gel techniques. With diffusion as the basis to introduce and remove chemical species into and out of the hydrogel, this method is suitable for smaller bulk geometries and thin films. Characterization of the cellulose nanofiber-palladium composite aerogels with scanning electron microscopy, X-ray diffractometry, thermal gravimetric analysis, nitrogen gas adsorption, electrochemical impedance spectroscopy, and cyclic voltammetry indicates a high surface area, metallized palladium porous structure.

A synthesis method for cellulose nanofiber biotemplated palladium composite aerogels is presented.The resulting composite aerogel materials offer potential for catalysis, sensing, and hydrogen gas storage applications.

Selüloz nanofiber Biotemkaplama Palladium kompozit Aerogels için sentez yöntemi

Here, a method to synthesize cellulose nanofiber biotemplated palladium composite aerogels is presented. Noble metal aerogel synthesis methods often ...