작품은 주로 국립 과학 재단 (NSF)에 의해 자금을, 화학 부문 (보너스 번호 CHE 1507370) 인정 했다. 아이 M. 카림 Wenhui 리 인정 3 m 부분 재정 지원 비-종신 교수 수상. 이 연구는 고급 광자 소스 (beamline 12-ID-C, 사용자 제안 허 튼 이야기-45774)의 리소스를 사용, 계약 번호 아래 Argonne 국립 연구소에 의해 과학의 암컷 사무실에는 미국 부서의 에너지 (도우) 사무실의 과학 사용자 시설 운영 드-AC02-06CH11357입니다. 저자는 Yubing Lu, SAXS 측량으로 그의 친절 한 도움에 대 한 버지니아 공대에서 화학 공학 학과에 박사 후보자를 감사 하 고 싶습니다. 제시 작품 통합 나노기술에 대 한 센터에서 부분적으로 실행 된, 과학의 미국 부서의 에너지 (도우) 사무실에 대 한 운영 하는 사무실의 과학 사용자 시설. 로스 알라모 스 국립 연구소, 차별 철폐, 기회 균등 고용주 이다 로스 알라모 스 국가 안보, LLC는, 드-AC52-06NA25396의 계약에 따라 미국 에너지 부의 국립 핵 보안 관리에 운영 됩니다.

보고서에 충돌의 관심 있다.

이 연구에서 우리는 상한 nucleation 및 금속 나노 입자의 성장에 ligands의 효과 검사 하는 강력한 방법론을 제시. 우리는 다른 용 매 (톨루엔 및 피리 딘)에서 Pd 나노 입자 합성 금속 전조와 위쪽으로는 ligand로 Pd 아세테이트를 사용 하 여. 우리 사용 현장에 SAXS 나노 (nucleation 이벤트), 입자의 농도 뿐만 아니라 감소 원자 (nucleation 및 성장 이벤트)의 농도 추출 하 여 두 실험 관찰 가능 개체 모델 ?...

금속 나노 입자의 제어 합성은 촉매, 태양광, 광학, 센서, 및 약 납품1,2,3, nanostructured 물질의 큰 응용 프로그램으로 인해 매우 중요 4,5. 특정 크기와 크기 분포와 나노 입자를 합성 하는 기본 입자 nucleation 및 성장 메커니즘을 이해 생명 이다. 그럼에도 불구 하 고, 그런 기준으로 나노 입자를 얻는 이해 합성 메커니즘 및 문학에서 사용할 수 있는 강력한 운동 모델의 부족에 느린 진행 때문에 나노 종합 커뮤니티를 도전 하고있다. 1950 년대, LaMer nucleation와 유황 sols의 성장 모델을 제안 nucleation 핵6,7의 확산 제어 성장 뒤의 버스트입니다. 이 제안 된 모델에서 그것은 가정 하는 단량체 농도 (때문에 감소 또는 전조의 분해) 증가 입자 nucleation 극복 될 수 있다, 중요 한과 포화, 에너지 장벽 위에 레벨은 일단 버스트 nucleation (균질 nucleation)의 결과로. 제안 된 버스트 nucleation, 단위체 농도 방울 및 중요 한과 포화 수준 이하로 떨어질 때, 때문에 nucleation 중지 합니다. 다음으로, 형성된 된 핵 추가 nucleation 이벤트가 발생 하는 동안 나노 입자 표면으로 단위체의 보급을 통해 성장 postulated는. 이 결과 효과적으로 분리 nucleation와 시간에 성장 하 고 성장 과정8동안 크기 분포를 제어. 이 모델은 다른 나노 입자 Ag9, 누구나10, CdSe11, Fe3O412등의 형성을 설명 하기 위해 사용 되었다. 그러나, 몇몇 연구는 고전 nucleation 이론 (CNT) 설명할 수 콜 로이드 나노 입자의 형성 특히 nucleation 및 성장의 중복은1,를 관찰 하는 금속 나노 입자에 대 한 설명 13,,1415,,1617. 이러한 연구 중 하나에서 Watzky와 핑크 이리듐 나노13, 있는 느린 연속 nucleation 겹치면 빠른 나노 표면 성장 (성장이 autocatalytic)의 형성 하는 2 단계 메커니즘을 설립. 빠른 autocatalytic 성장과 느린 nucleation Pd14,,1518, Pt19,20, Rh21 등 금속 나노 입자의 종류에 대 한 관찰도 했다 ,22. 개발 nucleation 및 성장 모델1,23,,2425는 ligands의 역할에 최근 전진에도 불구 하 고 제안 된 모델에서 종종 무시 됩니다. 그럼에도 불구 하 고, ligands 나노 크기14,,1526 형태학19,27 로 촉매 활동 및 선택도28 영향을 미치는 표시 됩니다. , 29. 예를 들어 양 외. 30 trioctylphosphine (맨 위)의 농도 변화 하 여 9.5 및 15 nm에서 이르기까지 Pd 나노 입자 크기를 제어 합니다. 마그네틱 나노 (Fe3O4)의 합성에 크기 눈에 띄게 감소 11에서 5 nm 60 1에서 리간드 (octadecylamine) 금속 전조 비율 증가. 흥미롭게도, Pt 나노 입자의 크기는 아민 ligands의 사슬 길이에 민감한 표시 했다 (예., n-hexylamine 및 octadecylamine), 긴 체인을 사용 하 여 작은 나노 크기를 얻을 수 있는 (즉,., octadecylamine)31
다른 농도는 ligands의 종류에 의해 발생 하는 크기 변경 nucleation 및 성장 속도에 ligands의 기여에 대 한 분명 한 증거 이다. 불행히도, 몇 가지 연구는 이러한 연구에, ligands의 역할에 대 한 설명, 여러 가정 자주 되었다 편의 위해는 차례로 이러한 모델 특정 조건32,33만 적용. 좀 더 구체적으로, Rempel 및 동료 상한 ligands의 양자 점 (CdSe)의 형성을 설명 하기 위해 운동 모델을 개발. 그러나, 그들의 연구, 나노 표면 ligand의 바인딩 어떤 주어진된 시간32평형에 간주 됩니다. 이 가정 큰 초과에서 ligands는 사실 만요 수 있습니다. 우리의 그룹은 최근 새로운 리간드 기반 모델14 전조 (금속 복잡 한)와 가역 반응14나노 입자의 표면 ligands를 상한의 바인딩을 위해 차지 하는 개발. 또한, 우리의 리간드 기반 모델 수 잠재적으로 사용할 수 다른 금속 나노 시스템에 합성 속도 ligands의 존재에 의해 영향을 받을 것.
현재 연구에서 우리 형성 및 다른 용 제 톨루엔 등 pyridine에에서 Pd 나노 입자의 성장 예측을 우리의 새로 개발된 된 리간드 기반 모델을 사용 합니다. 우리의 모델 입력에 대 한 현장에 SAXS 이용 되었다 합성 동안 나노 입자 및 크기 분포의 농도를. 크기 및 입자, 키네틱 모델링에 의해 보완의 농도 측정 nucleation 및 성장 속도에 더 정확한 정보를 추출할 수 있습니다. 더 이상 우리의 리간드 기반 모델, 금속 ligand 바인딩에 대 한 명시적으로 차지 하 고, 매우 예측 이며 원하는 크기와 나노 입자를 합성 절차를 디자인 하는 데 사용할 수 있습니다 설명 합니다.

<table><tbody><tr><td>palladium acetate (Pd(OAc)2)</td><td>ALDRICH</td><td>520764</td><td></td></tr><tr><td>anhydrous acetic acid</td><td>SIAL</td><td>338826</td><td></td></tr><tr><td>trioctylphosphine</td><td>ALDRICH</td><td>718165</td><td></td></tr><tr><td>pyridine</td><td>MilliporeSigma</td><td>PX2012-7</td><td></td></tr><tr><td>toluene</td><td>SIAL</td><td>244511</td><td></td></tr><tr><td>1-hexanol</td><td>SIAL</td><td>471402</td><td></td></tr><tr><td>N8 Horizon SAXS</td><td>Bruker</td><td>A32-X1</td><td></td></tr><tr><td>glovebox</td><td>Vaccum Atmospheres Co.</td><td>109035</td><td></td></tr><tr><td>MR HEI-TEC 115V Hotplate</td><td>Heidolph</td><td>5053000000</td><td></td></tr><tr><td>hotplate Monoblock insert</td><td>Heidolph</td><td>5058000800</td><td></td></tr><tr><td>heat-On 25-ml insert</td><td>Heidolph</td><td>5058006200</td><td></td></tr><tr><td>7 mL vials</td><td>SUPELCO</td><td>27518</td><td></td></tr><tr><td>micro stir bar PTFE&amp;nbsp;</td><td>VWR</td><td>58948-353</td><td></td></tr><tr><td>egg-Shaped Bars&amp;nbsp;</td><td>Fisherbrand&amp;trade;&amp;nbsp;</td><td>14-512-121</td><td></td></tr><tr><td>25 mL round bottom flasks</td><td>ALDRICH</td><td>Z167495</td><td></td></tr><tr><td>quartz capillary</td><td>Hampton Research</td><td>HR6-148</td><td></td></tr><tr><td>MATLAB R2016b</td><td>MathWorks</td><td></td><td></td></tr><tr><td>Bruker SAXS 1.0v</td><td>Bruker</td><td></td><td></td></tr><tr><td>Diffrac Measurement Center 4.0v</td><td>Bruker</td><td></td><td></td></tr></tbody></table>

ligand-mediated nucleation and growth of palladium metal nanoparticles

크기, 분포 및 콜 로이드 나노 입자의 안정성 크게 상한 ligands의 존재에 의해 영향을. 합성 반응 동안 ligands를 상한의 주요 기여에도 불구 하 고 콜 로이드 나노 입자의 nucleation 및 성장 속도 조절에 그들의 역할은 잘 이해 되지 않습니다. 이 작품 보여 줍니다 trioctylphosphine (맨 위)의 역할의 기계적 조사를 다른 용 매 (톨루엔 및 피리 딘)에서 Pd 나노 입자에 제자리에 SAXS 및 리간드 기반 운동 모델링을 사용 하 여. 다른 합성 조건 하에서 우리의 결과 공개 nucleation의 중복 및 모순 LaMer 형 nucleation 및 성장 모델 반응 동안 Pd 나노 입자의 성장. 모델은, 전조와 입자 제자리의 농도 뿐만 아니라 크기 진화를 잡으려고 필수적 이다 입자 표면에 대 한 바인딩 Pd-가기의 활동에 대 한 계정. 또한, 우리는 원하는 크기와 나노 입자를 합성 조건 설계 통해 리간드 기반 모델의 예측 능력을 설명 합니다. 제안 된 방법론 다른 합성 시스템에 적용 될 수 있다 하 고 따라서 콜 로이드 나노 입자의 예측 합성에 대 한 효과적인 전략으로 봉사 한다.

체계적으로 상한 ligands의 nucleation 및 성장 속도 론 변경 여부를 검토, 우리는 다음 두 가지 방법 했다: (i) 금속 ligand의 바인딩 이전 연구와 유사한 운동 모델에 고려 하지 않은 (즉,., nucleation 및 autocatalytic 성장) (ii) 전조와 표면에 나노 입자의 리간드를 상한의 가역 바인딩 모델에서 계정에 찍은 (즉., 리간드 기반 모델 프로토콜에서 설명). 톨루엔에 Pd 합성에 ?...

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

Ligand 중재 Nucleation 및 팔라듐 금속 나노 입자의 성장

이 작품의 주요 목표 상한n 원래의 작은 각 x 선 산란 (SAXS)와 리간드 기반 운동 모델링 난을 결합 하 여 팔라듐 나노 입자의 크기 조절에 에이전트의 역할을 명료 하 게 하는.

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

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10.3K 조회수.  Virginia Polytechnic Institute and State University. 이 작품의 주요 목표 상한n 원래의 작은 각 x 선 산란 (SAXS)와 리간드 기반 운동 모델링 난을 결합 하 여 팔라듐 나노 입자의 크기 조절에 에이전트의 역할을 명료 하 게 하는.

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

A Technique to Functionalize and Self-assemble Macroscopic Nanoparticle-ligand Monolayer Films onto Template-free Substrates

This protocol describes a self-assembly technique to create macroscopic monolayer films composed of ligand-coated nanoparticles1,2. The simple, robust and scalable technique efficiently functionalizes metallic nanoparticles with thiol-ligands in a miscible water/organic solvent mixture allowing for rapid grafting of thiol groups onto the gold nanoparticle surface. The hydrophobic ligands on the nanoparticles then quickly phase separate the nanoparticles from the aqueous based suspension and confine them to the air-fluid interface. This drives the ligand-capped nanoparticles to form monolayer domains at the air-fluid interface.&#160; The use of water-miscible organic solvents is important as it enables the transport of the nanoparticles from the interface onto template-free substrates.&#160; The flow is mediated by a surface tension gradient3,4 and creates macroscopic, high-density, monolayer nanoparticle-ligand films.&#160; This self-assembly technique may be generalized to include the use of particles of different compositions, size, and shape and may lead to an efficient assembly method to produce low-cost, macroscopic, high-density, monolayer nanoparticle films for wide-spread applications.

A simple, robust and scalable technique to functionalize and self-assemble macroscopic nanoparticle-ligand monolayer films onto template-free substrates is described in this protocol.

템플릿이없는 기판에 육안 나노 입자 - 리간드 단층 필름을 기능화 및 자기 조립 기술

This protocol describes a self-assembly technique to create macroscopic monolayer films composed of ligand-coated nanoparticles1,2. The simple, robust and ...

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화학

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family of easy accessible, very cheap, and air stable, but highly active and universally applicable C-C cross-coupling catalysts with an excellent functional group tolerance. Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1), the least stable complex within this series towards protons; e.g. in the form of water, allows an eased nanoparticle formation and hence, proved to be the most active Heck catalyst within this series at 100 &#176;C and is a very rare example of an effective and versatile catalyst system that efficiently operates under mild reaction conditions. Rapid and complete catalyst degradation under work-up conditions into phosphonates, piperidinium salts and other, palladium-containing decomposition products assure an easy separation of the coupling products from catalyst and ligands. The facile, cheap, and rapid synthesis of 1,1',1"-(phosphinetriyl)tripiperidine and 1 respectively, the simple and convenient use as well as its excellent catalytic performance in the Heck reaction at 100 &#176;C make 1 to one of the most attractive and greenest Heck catalysts available.
We provide here the visualized protocols for the ligand and catalyst syntheses as well as the reaction protocol for Heck reactions performed at 10 mmol scale at 100 &#176;C and show that this catalyst is suitable for its use in organic syntheses.

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions

Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1) is an easy accessible, cheap, and air stable, but highly active Heck catalyst with an excellent functional group tolerance that efficiently operates under mild reaction conditions to give the coupling products in very high yields.

온화한 반응 조건 하에서 팔라듐 - 디클로로 {비스 [(phosphinetriyl) tripiperidine 1,1 &#39;, 1 &#39;&#39;]} 의해 촉매 Mizoroki-헥 크로스 커플 링 반응

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family ...

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.

영가 코어 금속 나노 입자의 생성은 사용 N- (2- 아미노 에틸) -3- aminosilanetriol

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

Synthesis of Bimetallic Pt/Sn-based Nanoparticles in Ionic Liquids

We demonstrate a method for the synthesis of bimetallic nanoparticles consisting of Pt and Sn. A synthesis strategy is used in which the particular physico-chemical properties of ionic liquids (ILs) are exploited to control both nucleation and growth processes. The nanoparticles form colloidal sols of very high colloidal stability in the IL, which is particularly interesting in view of their use as quasi-homogeneous catalysts. Procedures for both nanoparticle extraction in conventional solvents and for nanoparticle precipitation are presented. The size, structure and composition of the synthesized nanocrystals are confirmed using inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDX). By this, we show that the nanocrystals are random-type alloy and of small (2-3 nm) size. The catalytic activity and selectivity in the hydrogenation of &#945;,&#946;-unsaturated aldehydes is tested in a semi-continuous batch-type reactor. In this context, the bimetallic Pt/Sn-based nanoparticles reveal a high selectivity towards the unsaturated alcohol.

A protocol for the synthesis of bimetallic nanoparticles in ionic liquids and the procedure of their catalytic testing in the selective hydrogenation of unsaturated aldehydes are described.

이온 액체의 바이메탈 Pt/Sn 기반 나노 입자의 합성

We demonstrate a method for the synthesis of bimetallic nanoparticles consisting of Pt and Sn. A synthesis strategy is used in which the particular ...

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.

금속 나노 입자의 정확 하 게 제어 증 착에 대 한 연속 흐름 촉매 반응 기

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

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.

셀룰로오스 나노 섬유 바이오 템플릿 팔라듐 복합 에어로겔에 대한 합성 방법

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

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.

표면 플라스몬 여기에 의해 콜로이드 Au 나노로드에 Pd의 포토포지션

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

Preparation of Silver-Palladium Alloyed Nanoparticles for Plasmonic Catalysis under Visible-Light Illumination

Localized surface plasmon resonance (LSPR) in plasmonic nanoparticles (NPs) can accelerate and control the selectivity of a variety of molecular transformations. This opens possibilities for the use of visible or near-IR light as a sustainable input to drive and control reactions when plasmonic nanoparticles supporting LSPR excitation in these ranges are employed as catalysts. Unfortunately, this is not the case for several catalytic metals such as palladium (Pd). One strategy to overcome this limitation is to employ bimetallic NPs containing plasmonic and catalytic metals. In this case, the LSPR excitation in the plasmonic metal can contribute to accelerate and control transformations driven by the catalytic component. The method reported herein focuses on the synthesis of bimetallic silver-palladium (Ag-Pd) NPs supported on ZrO2 (Ag-Pd/ZrO2) that acts as a plasmonic-catalytic system. The NPs were prepared by co-impregnation of corresponding metal precursors on the ZrO2 support followed by simultaneous reduction leading to the formation of bimetallic NPs directly on the ZrO2 support. The Ag-Pd/ZrO2 NPs were then used as plasmonic catalysts for the reduction of nitrobenzene under 425 nm illumination by LED lamps. Using gas chromatography (GC), the conversion and selectivity of the reduction reaction under the dark and light irradiation conditions can be monitored, demonstrating the enhanced catalytic performance and control over selectivity under LSPR excitation after alloying non-plasmonic Pd with plasmonic metal Ag. This technique can be adapted to a wide range of molecular transformations and NPs compositions, making it useful for the characterization of the plasmonic catalytic activity of different types of catalysis in terms of conversion and selectivity.

Presented here is a protocol for the synthesis of silver-palladium (Ag-Pd) alloy nanoparticles (NPs) supported on ZrO2 (Ag-Pd/ZrO2). This system allows for harvesting energy from visible light irradiation to accelerate and control molecular transformations. This is illustrated by nitrobenzene reduction under light irradiation catalyzed by Ag-Pd/ZrO2 NPs.

가시광선 조명 아래 플라스모닉 촉매용 실버 팔라듐 합금 나노 입자 의 준비

Localized surface plasmon resonance (LSPR) in plasmonic nanoparticles (NPs) can accelerate and control the selectivity of a variety of molecular ...

Studying the Effects of Temperature on the Nucleation and Growth of Nanoparticles by Liquid-Cell Transmission Electron Microscopy

Temperature control is a recent development that provides an additional degree of freedom to study nanochemistry by liquid cell transmission electron microscopy. In this paper, we describe how to prepare an in situ heating experiment for studying the effect of temperature on the formation of gold nanoparticles driven by radiolysis in water. The protocol of the experiment is fairly simple involving a special liquid cell with uniform heating capabilities up to 100 &#176;C, a liquid-cell TEM holder with flow capabilities and an integrated interface for controlling the temperature. We show that the nucleation and growth mechanisms of gold nanoparticles are drastically impacted by the temperature in liquid cell. Using STEM imaging and nanodiffraction, the evolution of the density, size, shape and atomic structure of the growing nanoparticles are revealed in real time. Automated image processing algorithms are exploited to extract useful quantitative data from video sequences, such as the nucleation and growth rates of nanoparticles. This approach provides new inputs for understanding the complex physico-chemical processes at play during the liquid-phase synthesis of nanomaterials.

Temperature control during liquid-phase electron microscopy experiments opens up new perspectives of studying the dynamic of nanoparticles in liquid environments mimicking their formation or application media. Using recently developed heating liquid cells, we directly observed the influence of temperature on the nucleation and growth processes of gold nanoparticles in water.

액체 세포 전송 전자 현미경 검사법에 의한 나노 입자의 핵 형성 및 성장에 온도의 효과 연구

Temperature control is a recent development that provides an additional degree of freedom to study nanochemistry by liquid cell transmission electron ...

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes

Ligands like amines are used in the colloidal synthesis approach to protect platinum nanoparticles (Pt NP&#39;s) from agglomeration. Normally, ligands like amines are removed by diverse pre-treatment procedures before use in heterogeneous catalysis as amines are considered as a catalyst poison. However, a possible beneficial influence of these surface modifiers on hydrogenation reactions, which is known from spectator species on metal surfaces, is often neglected.
Therefore, amine-stabilized Pt nanoparticles supported by titania (P25) were used without any pre-treatment in order to elucidate a possible influence of the ligand in liquid phase hydrogenation reactions. The catalytic activity of amine-stabilized Pt nanoparticles of two different sizes was investigated in a double-walled stirring tank reactor at 69 &#176;C to 130 &#176;C and 1 atm hydrogen pressure. The conversion of cyclohexene to cyclohexane was determined by gas chromatography (GC) and was compared to ligand-free Pt particles. All catalysts were checked before and after reaction by transmission electron spectroscopy (TEM) and X-ray photoelectron spectroscopy (XPS) for possible changes in size, shape, and ligand shell. The hydrogenation of cyclohexene in liquid phase revealed a higher conversion for amine-stabilized Pt nanoparticles on titania than the ligand-free particles. The hydrogenation of 5-methylfurfural (5-MF) was chosen for a further test reaction, since the hydrogenation of &#945;, &#946;-unsaturated aldehydes is more complex and exhibits various reaction paths. However, XPS and infrared spectroscopy (IR) proved that 5-MF acts as catalyst poison at the given reaction conditions.

This protocol shows a convenient method for comparing the catalytic properties of supported platinum catalysts, synthesized by deposition of nanosized colloids or by impregnation. The hydrogenation of cyclohexene serves as a model reaction to determine the catalytic activity of the catalysts.

알켄과 알데히드의 수소화 동안 티타니아에 지지된 아민 안정화 및 리간드가 없는 백금 나노입자에서의 촉매 반응

Ligands like amines are used in the colloidal synthesis approach to protect platinum nanoparticles (Pt NP&#39;s) from agglomeration. Normally, ligands ...