Name: photochemical oxidative growth of iridium oxide nanoparticles on cdse@cds nanorods
Uploaded: 2016-02-11T15:00:00.000+00:00
Duration: 5 min 41 s
Description: Watch this Scientific Journal Video about Photochemical Oxidative Growth of Iridium Oxide Nanoparticles on CdSe@CdS Nanorods at JoVE.com

وأيد هذا البحث من قبل برنامج I-CORE لجنة التخطيط والميزانية ومؤسسة العلوم إسرائيل (منحة رقم 152/11). نشكر كلية Schulich الكيمياء والتخنيون - معهد تكنولوجي لإسرائيل لحزمة المختبرات وبدء التشغيل تجديده. كما نشكر الجمعية الملكية للكيمياء للحصول على إذن في تكييف المواد من http://dx.doi.org/10.1039/C4TA06164K للاستخدام في هذه المخطوطة. الدكتور Kalisman بفضل زمالة ما بعد الدكتوراه Schulich لدعمهم. نشكر الدكتور يارون كوفمان لمساعدته مع HR-تيم وHAADF وكذلك الدكتور كميرا ينفلد لمساعدتها مع توصيف XPS.

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تركيب البذور سيلينيد الكادميوم وسيلينيد الكادميوم @ أقراص مدمجة المصنف قضبان قد درست جيدا 21،24،25. تعديلات طفيفة على المبالغ، ودرجات الحرارة، ومرات لخطوات تركيب هذه الجزيئات الركيزة يمكن استخدامها لهجتهم طول وقطر، و / أو التشكل. بروتوكول الاصطناعية الموصوفة هن?...

يعرض ضوئي حلا جذابا واعدة لتوليد الطاقة المتجددة والتطبيقات البيئية الأخرى مثل معالجة المياه وتنقية الهواء 1-3. تقسيم المياه بشكل عام، مدفوعا الطاقة الشمسية، يمكن أن يكون مصدرا للوقود الهيدروجين النظيفة والمتجددة. ومع ذلك، على الرغم من عقود من البحث، ولم أدرك النظم التي هي مستقرة وفعالة بما فيه الكفاية للاستخدام العملي. كلا photodeposition وضوئي بوساطة أشباه الموصلات الاعتماد على نفس الآلية لفصل ولدت صورة أزواج الإلكترونات حفرة، ورميهم إلى السطح حيث يمكن الشروع في تفاعلات الأكسدة والاختزال. أوجه التشابه بين هاتين العمليتين تجعل photodeposition أداة الاصطناعية جذابة للمجال التحفيز الضوئي 4-6. ومن المتوقع أن يستغرق إنتاج حفاز ضوئي إلى آفاق جديدة وغير مستكشفة هذا الأسلوب. قد يحتمل تقديم السيطرة البكر على الترتيب المكانيمن المكونات المختلفة في heterostructures، وتعزيز القدرة على بناء أنظمة جسيمات متناهية الصغر المتطورة. في نهاية المطاف طريقة سوف تجلب لنا خطوة واحدة لتحقيق أحد ضوئي كفاءة لتحويل الطاقة الشمسية مباشرة إلى وقود. نحن التحقيق في النمو من حديد (2)، وشارك في حافز، كما هو معروف أن تكون حافزا فعالا للأكسدة المياه 7-11. تم استخدام هيكل الانضباطي من النقطة الكمومية (سيلينيد الكادميوم) جزءا لا يتجزأ من الكروم (كبريتيد الكادميوم) 12،13 لدينا ضوئي الركيزة 14،15. ومن غير محدد حاليا ما إذا كان مسار الأكسدة يحدث عن طريق المسار بوساطة، أو بسبب هجوم حفرة المباشر. هنا، لدينا معرفة والسيطرة على ثقوب photogenerated في heterostructure أشباه الموصلات يمكن تسخيرها لدراسة الميكانيكية للتفاعلات الأكسدة. وقد أصبح هذا ممكنا من العمارة الركيزة، مما يسهل توطين الثقوب تقتصر 16،17 وتشكيل لموقع متميز تفاعل الأكسدة على قضيب. استخدام المواد النانوية مع الناقل مسؤولا محلية يمكن استغلالها للدراسات الميكانيكية للتفاعلات الأكسدة والاختزال بواسطة فحص بسيط من المنتجات. وبهذه الطريقة photodeposition يمكن استخدامها في تحقيق فريد من كلا الحد من أكسدة مسارات رد فعل. هذا مثال واحد من الاحتمالات الجديدة والمثيرة التي يوفرها مزيج من photodeposition وأحدث الغروية التوليف 18-20. لقد أصبح السعي إلى تطوير ضوئي فعالة لتقسيم المياه وتحويل الطاقة المتجددة إلى التوجه مهم داخل المجتمع المواد. وقد حفز هذا الاهتمام العالمي في أقراص مدمجة، والذي يعرف أن تكون نشطة للغاية لإنتاج الهيدروجين، على الرغم من تعثر نتيجة عدم الاستقرار الضوئي. عملنا هنا يعامل كعب أخيل للمادة. IRO 2 زينت أقراص مدمجة قضبان سيلينيد الكادميوم @ تثبت الاستقرار الضوئي ملحوظا تحت إضاءة لفترات طويلة في نقيةماء.

<table><tbody><tr><td>Sulfur (S)</td><td>Sigma</td><td>84683</td><td></td></tr><tr><td>Selenium (Se)</td><td>Sigma</td><td>229865</td><td></td></tr><tr><td>Cadmium Oxide (CdO)</td><td>Sigma</td><td>202894</td><td>Highly Toxic</td></tr><tr><td>n-Octadecylphosphonic acid (ODPA)</td><td>Sigma</td><td>715166</td><td></td></tr><tr><td>Propylphosphonic acid (PPA)</td><td>Sigma</td><td>305685</td><td>Highly regulated in some countries and regions</td></tr><tr><td>Butylphosphonic acid (BPA)</td><td>Sigma</td><td>737933</td><td>Alternative to PPA</td></tr><tr><td>Hexylphosphonic acid (HPA)</td><td>Sigma</td><td>750034</td><td>Alternative to PPA</td></tr><tr><td>Trioctylphosphonic oxide (TOPO)</td><td>Sigma</td><td>346187</td><td></td></tr><tr><td>Tri-n-octylphosphine, 97% (TOP)</td><td>Sigma</td><td>718165</td><td>Air sensitive</td></tr><tr><td>Spectrochemical Stirbar</td><td>Sigma</td><td>Z363545</td><td></td></tr><tr><td>Sodium Hydroxide</td><td>Sigma</td><td>S5881</td><td></td></tr><tr><td>Methanol</td><td>Sigma</td><td>322415</td><td></td></tr><tr><td>Toluene</td><td>Sigma</td><td>244511</td><td></td></tr><tr><td>Hexane</td><td>Sigma</td><td>296090</td><td></td></tr><tr><td>Octylamine</td><td>Sigma</td><td>74988</td><td></td></tr><tr><td>Nonanoic Acid</td><td>Sigma</td><td>N5502</td><td></td></tr><tr><td>Isopropanol</td><td>Sigma</td><td>278475</td><td></td></tr><tr><td>Mercaptoundecanoic Acid (MUA)</td><td>Sigma</td><td>674427</td><td></td></tr><tr><td>Tetramethylammonium Hydroxide (TMAH)</td><td>Sigma</td><td>T7505</td><td></td></tr><tr><td>Apiezon H Grease (high temperature grease)</td><td>Sigma</td><td>Z273562</td><td></td></tr><tr><td>Sodium Persulfate</td><td>Sigma</td><td>216232</td><td></td></tr><tr><td>Sodium Nitrate</td><td>Sigma</td><td>229938</td><td></td></tr><tr><td>Sodium Hexachloroiridate(III) hydrate</td><td>Sigma</td><td>288160</td><td></td></tr><tr><td>Mounted 455 nm LED</td><td>Thorlabs</td><td>M455L3</td><td></td></tr><tr><td>Cuvette Holder</td><td>Thorlabs</td><td>CVH100</td><td></td></tr><tr><td>25 ml 3-neck Round Bottom Flask</td><td>Chemglass</td><td>CG-1524-A-02</td><td></td></tr><tr><td>Liebig Condensor</td><td>Chemglass</td><td>CG-1218-A-20</td><td></td></tr><tr><td>T-Joint Adapter</td><td>Chemglass</td><td>AF-0509-10</td><td></td></tr></tbody></table>

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).

تم جمع الميكروسكوب الإلكتروني انتقال (تيم) من أجل أن نرى توزيع أكسيد الايريديوم على قضبان المصنفة (الشكل 1). وقبل pipetting قطرة من جزيئات المذاب على شبكة تيم إعداد العينات تيم. استخدمت حيود الأشعة السينية (XRD، الشكل 2) والأشعة السينية ال?...

Watch this Scientific Journal Video about Photochemical Oxidative Growth of Iridium Oxide Nanoparticles on CdSe@CdS Nanorods at JoVE.com

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

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

الضوئية مؤكسد نمو إيريديوم أكسيد النانوية على سيلينيد الكادميوم @ أقراص مدمجة نانواعواد

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

photochemical-oxidative-growth-iridium-oxide-nanoparticles-on-cdsecds

Research

JoVE Journal

Chemistry

9.5K Views.  Technion – Israel Institute of Technology. A protocol for the photochemical oxidative growth of small crystalline iridium oxide nanoparticles on the surface of CdSe@CdS seeded rod nanoparticles is presented.

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

Compact Quantum Dots for Single-molecule Imaging

Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology 1-4. To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study.
Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation 5. Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large 4,6,7.
Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past 8,9. The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an insulating CdyZn1-yS shell, further coated with a multidentate polymer ligand modified with short polyethylene glycol (PEG) chains (Figure 1). Compared with conventional CdSe nanocrystals, HgxCd1-xSe alloys offer greater quantum yields of fluorescence, fluorescence at red and near-infrared wavelengths for enhanced signal-to-noise in cells, and excitation at non-cytotoxic visible wavelengths. Multidentate polymer coatings bind to the nanocrystal surface in a closed and flat conformation to minimize hydrodynamic size, and PEG neutralizes the surface charge to minimize nonspecific binding to cells and biomolecules. The end result is a brightly fluorescent nanocrystal with emission between 550-800 nm and a total hydrodynamic size near 12 nm. This is in the same size range as many soluble globular proteins in cells, and substantially smaller than conventional PEGylated QDs (25-35 nm).

We describe the preparation of colloidal quantum dots with minimized hydrodynamic size for single-molecule fluorescence imaging. Compared to conventional quantum dots, these nanoparticles are similar in size to globular proteins and are optimized for single-molecule brightness, stability against photodegradation, and resistance to nonspecific binding to proteins and cells.

الكم النقاط المدمجة لواحدة جزيء التصوير

Single-molecule imaging is an important tool for  understanding the mechanisms of biomolecular function and for visualizing the  spatial and temporal ...

Engineering

Harvesting Solar Energy by Means of Charge-Separating Nanocrystals and Their Solids

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials offering a superior control over the spatial distribution of charge carriers across material interfaces. As this study demonstrates, a combination of donor-acceptor nanocrystal (NC) domains in a single nanoparticle can lead to the realization of efficient photocatalytic1-5 materials, while a layered assembly of donor- and acceptor-like nanocrystals films gives rise to photovoltaic materials.
Initially the paper focuses on the synthesis of composite inorganic nanocrystals, comprising linearly stacked ZnSe, CdS, and Pt domains, which jointly promote photoinduced charge separation. These structures are used in aqueous solutions for the photocatalysis of water under solar radiation, resulting in the production of H2 gas. To enhance the photoinduced separation of charges, a nanorod morphology with a linear gradient originating from an intrinsic electric field is used5. The inter-domain energetics are then optimized to drive photogenerated electrons toward the Pt catalytic site while expelling the holes to the surface of ZnSe domains for sacrificial regeneration (via methanol). Here we show that the only efficient way to produce hydrogen is to use electron-donating ligands to passivate the surface states by tuning the energy level alignment at the semiconductor-ligand interface. Stable and efficient reduction of water is allowed by these ligands due to the fact that they fill vacancies in the valence band of the semiconductor domain, preventing energetic holes from degrading it. Specifically, we show that the energy of the hole is transferred to the ligand moiety, leaving the semiconductor domain functional. This enables us to return the entire nanocrystal-ligand system to a functional state, when the ligands are degraded, by simply adding fresh ligands to the system4.
To promote a photovoltaic charge separation, we use a composite two-layer solid of PbS and TiO2 films. In this configuration, photoinduced electrons are injected into TiO2 and are subsequently picked up by an FTO electrode, while holes are channeled to a Au electrode via PbS layer6. To develop the latter we introduce a Semiconductor Matrix Encapsulated Nanocrystal Arrays (SMENA) strategy, which allows bonding PbS NCs into the surrounding matrix of CdS semiconductor. As a result, fabricated solids exhibit excellent thermal stability, attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces, and show compelling light-harvesting performance in prototype solar cells7.

A general strategy for the development of charge-separating semiconductor nanocrystal composites deployable for solar energy production is presented. We show that assembly of donor-acceptor nanocrystal domains in a single nanoparticle geometry gives rise to a photocatalytic function, while bulk-heterojunctions of donor-acceptor nanocrystal films can be used for photovoltaic energy conversion.

حصاد الطاقة الشمسية من وسائل البلورات النانوية المسؤول فصل المواد الصلبة وتلك

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials ...

Seeded Synthesis of CdSe/CdS Rod and Tetrapod Nanocrystals

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded synthesis strategy is used in which spherical seeds of CdSe are prepared first using a hot-injection technique. By controlling the crystal structure of the seed to be either wurtzite or zinc-blende, the subsequent hot-injection growth of CdS off of the seed results in either a rod-shaped or tetrapod-shaped nanocrystal, respectively. The phase and morphology of the synthesized nanocrystals are confirmed using X-ray diffraction and transmission electron microscopy, demonstrating that the nanocrystals are phase-pure and have a consistent morphology. The extinction coefficient and quantum yield of the synthesized nanocrystals are calculated using UV-Vis absorption spectroscopy and photoluminescence spectroscopy. The rods and tetrapods exhibit extinction coefficients and quantum yields that are higher than that of the bare seeds. This synthesis demonstrates the precise arrangement of materials that can be achieved at the nanoscale by using a seeded synthetic approach.

A protocol for the seeded synthesis of rod-shaped and tetrapod-shaped multicomponent nanostructures consisting of CdS and CdSe is presented.

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded ...

Synthesis of Ligand-free CdS Nanoparticles within a Sulfur Copolymer Matrix

Aliphatic ligands are typically used during the synthesis of nanoparticles to help mediate their growth in addition to operating as high-temperature solvents. These coordinating ligands help solubilize and stabilize the nanoparticles while in solution, and can influence the resulting size and reactivity of the nanoparticles during their formation. Despite the ubiquity of using ligands during synthesis, the presence of aliphatic ligands on the nanoparticle surface can result in a number of problems during the end use of the nanoparticles, necessitating further ligand stripping or ligand exchange procedures. We have developed a way to synthesize cadmium sulfide (CdS) nanoparticles using a unique sulfur copolymer. This sulfur copolymer is primarily composed of elemental sulfur, which is a cheap and abundant material. The sulfur copolymer has the advantages of operating both as a high temperature solvent and as a sulfur source, which can react with a cadmium precursor during nanoparticle synthesis, resulting in the generation of ligand free CdS. During the reaction, only some of the copolymer is consumed to produce CdS, while the rest remains in the polymeric state, thereby producing a nanocomposite material. Once the reaction is finished, the copolymer stabilizes the nanoparticles within a solid polymeric matrix. The copolymer can then be removed before the nanoparticles are used, which produces nanoparticles that do not have organic coordinating ligands. This nascent synthesis technique presents a method to produce metal-sulfide nanoparticles for a wide variety of applications where the presence of organic ligands is not desired.

Herein we present a method to synthesize ligand-free cadmium sulfide (CdS) nanoparticles based on a unique sulfur copolymer. The sulfur copolymer operates as a high temperature solvent and a sulfur source during the nanoparticle synthesis and stabilizes the nanoparticles after the reaction.

تركيب خالية من يجند أقراص مدمجة النانوية داخل مصفوفة الكبريت كوبوليمر

Aliphatic ligands are typically used during the synthesis of nanoparticles to help mediate their growth in addition to operating as high-temperature ...

Hydroquinone Based Synthesis of Gold Nanorods

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the synthetic methods for the preparation of gold nanorods are still not fully optimized. In this paper we describe a new, highly efficient, two-step protocol based on the use of hydroquinone as a mild reducing agent. Our approach allows the preparation of nanorods with a good control of size and aspect ratio (AR) simply by varying the amount of hexadecyl trimethylammonium bromide (CTAB) and silver ions (Ag+) present in the "growth solution". By using this method, it is possible to markedly reduce the amount of CTAB, an expensive and cytotoxic reagent, necessary to obtain the elongated shape. Gold nanorods with an aspect ratio of about 3 can be obtained in the presence of just 50 mM of CTAB (versus 100 mM used in the standard protocol based on the use of ascorbic acid), while shorter gold nanorods are obtained using a concentration as low as 10 mM.

This paper describes a protocol for the synthesis of gold nanorods, based on the use of hydroquinone as reducing agent, plus the different mechanisms for controlling their size and aspect ratio.

الهيدروكينون القائم على توليف نانواعواد الذهب

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the ...

Synthesis of Hierarchical ZnO/CdSSe Heterostructure Nanotrees

A two-step chemical vapor deposition procedure is here employed to prepare tree-like hierarchical ZnO/CdSSe hetero-nanostructures. The structures are composed of CdSSe branches grown on ZnO nanowires that are vertically aligned on a transparent sapphire substrate. The morphology was measured via scanning electron microscopy. The crystal structure was determined by X-ray powder diffraction analysis. Both the ZnO stem and CdSSe branches have a predominantly wurtzite crystal structure. The mole ratio of S and Se in the CdSSe branches was measured by energy dispersive X-ray spectroscopy. The CdSSe branches result in strong visible light absorption. Photoluminescence (PL) spectroscopy showed that the stem and branches form a type-II heterojunction. PL lifetime measurements showed a decrease in the lifetime of emission from the trees when compared to emission from individual ZnO stems or CdSSe branches and indicate fast charge transfer between CdSSe and ZnO. The vertically aligned ZnO stems provide a direct electron transport pathway to the substrate and allow for efficient charge separation after photoexcitation by visible light. The combination of the abovementioned properties makes ZnO/CdSSe nanotrees promising candidates for applications in solar cells, photocatalysis, and opto-electronic devices.

Here, we prepare and characterize novel tree-like hierarchical ZnO/CdSSe nanostructures, where CdSSe branches are grown on vertically aligned ZnO nanowires. The resulting nanotrees are a potential material for solar energy conversion and other opto-electronic devices.

توليف الهرمي أكسيد الزنك / CdSSe Heterostructure Nanotrees

A two-step chemical vapor deposition procedure is here employed to prepare tree-like hierarchical ZnO/CdSSe hetero-nanostructures. The structures are ...

Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be covalently and site-specifically linked via their end facets, resulting in polymer-like linear or branched chains. The linking procedure begins with a cation-exchange process in which the end facets of the cadmium chalcogenide NCs are first converted to silver chalcogenide. This is followed by the selective removal of ligands at their surface. This results in cadmium chalcogenide NCs with highly reactive silver chalcogenide end facets that spontaneously fuse upon contact with each other, thereby establishing an interparticle facet-to-facet attachment. Through the judicious choice of precursor concentrations, an extensive network of linked NCs can be produced. Structural characterization of the linked NCs is carried out via low- and high-resolution transmission electron microscopy (TEM), as well as energy-dispersive X-ray spectroscopy, which confirm the presence of silver chalcogenide domains between chains of cadmium chalcogenide NCs.

A protocol detailing how shape-anisotropic colloidal cadmium chalcogenide nanocrystals can be covalently linked via their end facets is presented here.

جانبا إلى جانب ربط النانو تشالكوجينيدي شكل متباين الكادميوم غرواني

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be ...

Ligand-Mediated Nucleation and Growth of Palladium Metal Nanoparticles

The size, size distribution and stability of colloidal nanoparticles are greatly affected by the presence of capping ligands. Despite the key contribution of capping ligands during the synthesis reaction, their role in regulating the nucleation and growth rates of colloidal nanoparticles is not well understood. In this work, we demonstrate a mechanistic investigation of the role of trioctylphosphine (TOP) in Pd nanoparticles in different solvents (toluene and pyridine) using in situ SAXS and ligand-based kinetic modeling. Our results under different synthetic conditions reveal the overlap of nucleation and growth of Pd nanoparticles during the reaction, which contradicts the LaMer-type nucleation and growth model. The model accounts for the kinetics of Pd-TOP binding for both, the precursor and the particle surface, which is essential to capture the size evolution as well as the concentration of particles in situ. In addition, we illustrate the predictive power of our ligand-based model through designing the synthetic conditions to obtain nanoparticles with desired sizes. The proposed methodology can be applied to other synthesis systems and therefore serves as an effective strategy for predictive synthesis of colloidal nanoparticles.

The main goal of this work is to elucidate the role of capping agents in regulating the size of palladium nanoparticles by combining in situ small angle x-ray scattering (SAXS) and ligand-based kinetic modeling.

يجند بوساطة التنو ونمو البلاديوم معدنية جسيمات نانوية

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

A Continuous-flow Photocatalytic Reactor for the Precisely Controlled Deposition of Metallic Nanoparticles

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic nanoparticles is developed. Guidelines for the replication of the reactor and its operation are provided in detail. Three different composite systems (Pt/graphene, Pt/TiO2, and Au/TiO2) with monodisperse and uniformly distributed particles are produced by this reactor, and the photodeposition mechanism, as well as the synthesis optimization strategy, are discussed. The synthesis methods and their technical aspects are described comprehensively. The role of the ultraviolet (UV) dose (in each excitation pulse) on the photodeposition process is investigated and the optimum values for each composite system are provided.

For a continuous and scalable synthesis of noble-metal-based nanocomposites, a novel photocatalytic reactor is developed and its structure, operation principles, and product quality optimization strategies are described.

مفاعل بهوتوكاتاليتيك تدفق مستمر لترسب الجسيمات النانوية المعدنية التي تسيطر عليها على وجه التحديد

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic ...

Photodeposition of Pd onto Colloidal Au Nanorods by Surface Plasmon Excitation

A protocol is described to photocatalytically guide Pd deposition onto Au nanorods (AuNR) using surface plasmon resonance (SPR). Excited plasmonic hot electrons upon SPR irradiation drive reductive deposition of Pd on colloidal AuNR in the presence of [PdCl4]2-. Plasmon-driven reduction of secondary metals potentiates covalent, sub-wavelength deposition at targeted locations coinciding with electric field &#8220;hot-spots&#8221; of the plasmonic substrate using an external field (e.g., laser). The process described herein details a solution-phase deposition of a catalytically-active noble metal (Pd) from a transition metal halide salt (H2PdCl4) onto aqueously-suspended, anisotropic plasmonic structures (AuNR). The solution-phase process is amenable to making other bimetallic architectures. Transmission UV-vis monitoring of the photochemical reaction, coupled with ex situ XPS and statistical TEM analysis, provide immediate experimental feedback to evaluate properties of the bimetallic structures as they evolve during the photocatalytic reaction. Resonant plasmon irradiation of AuNR in the presence of [PdCl4]2- creates a thin, covalently-bound Pd0 shell without any significant dampening effect on its plasmonic behavior in this representative experiment/batch. Overall, plasmonic photodeposition offers an alternative route for high-volume, economical synthesis of optoelectronic materials with sub-5 nm features (e.g., heterometallic photocatalysts or optoelectronic interconnects).

A protocol for anisotropic photodeposition of Pd onto aqueously-suspended Au nanorods via localized surface plasmon excitation is presented.

الترسب الضوئي للPd on الغروية Au Nanorods بواسطة الإثارة البلازمون السطحية

A protocol is described to photocatalytically guide Pd deposition onto Au nanorods (AuNR) using surface plasmon resonance (SPR). Excited plasmonic hot ...