Synthesis Of Colloidal Nanoparticles Research Articles

Metal Nanocrystal Formation during Liquid Phase Transmission Electron Microscopy: Thermodynamics and Kinetics of Precursor Conversion, Nucleation, and Growth

Colloidal nanoparticle synthesis involves a complex combination of physical and chemical processes that transform a liquid phase metal precursor into nanoparticles, each containing thousands to mil...

Synthesis of crosslinked poly(methacrylic acid) shell/lipid core colloidal nanoparticles via L-in-Lm interfacial polymerization and their pH responsiveness

In this present work, the synthesis of colloidal nanoparticles with crosslinked poly(methacrylic acid) (PMAA)-shell and lipid core via L-in-Lm interfacial polymerization was illustrated. The oil-in-water pre-emulsion of lipid (L) dispersed in an aqueous continuous phase containing monomer (Lm) was initially formed, and the polymerization took place at the oil/water interface. The oil phase contained sunflower oil (SF) as a model lipid and benzoyl peroxide (BPO) initiator, while an aqueous continuous phase consisted of methacrylic acid (MAA) as a model monomer, N,N’-methylenebis(acrylamide) (MBA) as cross-linker, and sodium dodecyl sulfate (SDS) as surfactant. After polymerization at elevated temperature, crosslinked PMAA was located on the surface of sunflower oil droplets as a shell layer, indicating that MAA monomer and MBA cross-linker were involved in the polymerization at the oil/water interface. The detailed investigation on the effects of polymerization parameters (e.g. polymerization temperature, initiator, monomer, surfactant, and cross-linker concentrations) was conducted. The physico-chemical properties, such as particle size, morphology, chemical composition, and pH-responsiveness were then determined. This synthetic route can provide PMAA-shell nanoparticles with accessibility and availability of carboxyl functional groups, and pH responsiveness that could be useful for various applications.

Influence of the phosphorus source on iron phosphide nanoparticle synthesis for hydrogen evolution reaction catalysis

Iron phosphide (FeP) is in the spotlight as a hydrogen evolution reaction (HER) catalyst due to its cost efficiency, good catalytic activity, and stability within a wide pH range. However, there is still a need to synthesize FeP nanoparticles (NPs) with systematic analysis to improve their catalytic activity. Herein, we report FeP NPs synthesized with various phosphorus sources (TOP, trioctylphosphine; TPP, triphenylphosphite; TEAP, tris(diethylamino)phosphine; and TBP, tri-n-butylphosphine) via phosphorization reaction. We clearly demonstrate that the HER activity of the catalyst based on the FeP phase is dependent on the choice of phosphorus source used in the colloidal NP synthesis. Among the samples, FeP NPs synthesized with TPP achieved the highest HER activity with an overpotential of 76 mV at 10 mA cm−2 in 0.5 M H2SO4. Our results reveal a critical aspect of colloidal synthesis to achieve enhanced catalytic activity in the synthesis of transition metal phosphide NPs.

Correction to “Investigating Particle Size Effects in Catalysis by Applying a Size-Controlled and Surfactant-Free Synthesis of Colloidal Nanoparticles in Alkaline Ethylene Glycol: Case Study of the Oxygen Reduction Reaction on Pt”

ADVERTISEMENT RETURN TO ISSUEPREVCorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to “Investigating Particle Size Effects in Catalysis by Applying a Size-Controlled and Surfactant-Free Synthesis of Colloidal Nanoparticles in Alkaline Ethylene Glycol: Case Study of the Oxygen Reduction Reaction on Pt”Jonathan Quinson*Jonathan QuinsonMore by Jonathan Quinsonhttp://orcid.org/0000-0002-9374-9330, Masanori InabaMasanori InabaMore by Masanori Inaba, Sarah NeumannSarah NeumannMore by Sarah Neumann, Andreas A. SwaneAndreas A. SwaneMore by Andreas A. Swane, J. BucherJ. BucherMore by J. Bucher, Søren B. SimonsenSøren B. SimonsenMore by Søren B. Simonsenhttp://orcid.org/0000-0001-7172-1225, Luise Theil KuhnLuise Theil KuhnMore by Luise Theil Kuhn, Jacob J. K. KirkensgaardJacob J. K. KirkensgaardMore by Jacob J. K. Kirkensgaardhttp://orcid.org/0000-0001-6265-0314, Kirsten M. Ø. JensenKirsten M. Ø. JensenMore by Kirsten M. Ø. Jensenhttp://orcid.org/0000-0003-0291-217X, Mehtap OezaslanMehtap OezaslanMore by Mehtap Oezaslanhttp://orcid.org/0000-0001-8545-7576, Sebastian KunzSebastian KunzMore by Sebastian Kunz, and Matthias Arenz*Matthias ArenzMore by Matthias Arenzhttp://orcid.org/0000-0001-9765-4315Cite this: ACS Catal. 2020, 10, 4, 2692–2693Publication Date (Web):February 10, 2020Publication History Published online10 February 2020Published inissue 21 February 2020https://doi.org/10.1021/acscatal.0c00452Copyright © 2020 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1254Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (720 KB) Get e-AlertsSUBJECTS:Metal nanoparticles,Mixtures,Platinum,Precursors,X-ray scattering Get e-Alerts

A Directed Route to Colloidal Nanoparticle Synthesis of the Copper Selenophosphate Cu3 PSe4.

The first colloidal nanoparticle synthesis of the copper selenophosphate Cu3 PSe4 , a promising new material for photovoltaics, is reported. Because the formation of binary copper selenide impurities seemed to form more readily, two approaches were developed to install phosphorus bonds directly: 1) the synthesis of molecular P4 Se3 and subsequent reaction with a copper precursor, (P-Se)+Cu, and 2) the synthesis of copper phosphide, Cu3 P, nanoparticles and subsequent reaction with a selenium precursor, (Cu-P)+Se. The isolation and purification of Cu3 P nanoparticles and subsequent selenization yielded phase-pure Cu3 PSe4 . Solvent effects and Se precursor reactivities were elucidated and were key to understanding the final reaction conditions.

A Directed Route to Colloidal Nanoparticle Synthesis of the Copper Selenophosphate Cu3PSe4

AbstractThe first colloidal nanoparticle synthesis of the copper selenophosphate Cu3PSe4, a promising new material for photovoltaics, is reported. Because the formation of binary copper selenide impurities seemed to form more readily, two approaches were developed to install phosphorus bonds directly: 1) the synthesis of molecular P4Se3 and subsequent reaction with a copper precursor, (P‐Se)+Cu, and 2) the synthesis of copper phosphide, Cu3P, nanoparticles and subsequent reaction with a selenium precursor, (Cu‐P)+Se. The isolation and purification of Cu3P nanoparticles and subsequent selenization yielded phase‐pure Cu3PSe4. Solvent effects and Se precursor reactivities were elucidated and were key to understanding the final reaction conditions.

Silver Chlorobromide Nanocubes: A Class of Reactive Templates for Synthesizing Nanoplates and Nanocages of Silver Thiolates

ABSTRACTUniform silver chlorobromide nanocubes have been used to regulate the availability of an extremely low concentration of Ag+ that react with different thiol molecules to form silver thiolate nanoplates with high controllability. The sacrificial silver chlorobromide nanocubes also serve as templates to provide surface nucleation sites for forming the silver thiolate nanoplates, which grow against the surfaces of the nanocubes to organize into nanocages upon the consumption of the entire nanocubes. The precise regulation of the extremely low concentration of Ag+ prevents the uncontrolled fast reaction with thiol molecules and the formation of irregular silver thiolate particles. This method represents a versatile strategy to control the reaction rate of fast reactions involving in the synthesis of colloidal nanoparticles, thus enabling the synthesis of uniform nanoparticles with desirable parameters.

In Situ Synchrotron X‐ray Characterization Shining Light on the Nucleation and Growth Kinetics of Colloidal Nanoparticles

AbstractRational synthesis of colloidal nanoparticles with desirable properties relies on precise control over the nucleation and growth kinetics, which is still not well understood. The recent development of in situ high energy synchrotron X‐ray techniques offers an excellent opportunity to quantitatively monitor the growth trajectories of colloidal nanoparticles in real time under real reaction conditions. The time‐resolved, quantitative data of the growing colloidal nanoparticles are unique to reveal the mechanism of nanoparticle formation and determine the corresponding intrinsic kinetic parameters. This review discusses the kinetics of major steps of forming colloidal nanoparticles and the capability of in situ synchrotron X‐ray techniques in studying the corresponding kinetics.

In Situ Synchrotron X-ray Characterization Shining Light on the Nucleation and Growth Kinetics of Colloidal Nanoparticles.

Rational synthesis of colloidal nanoparticles with desirable properties relies on precise control over the nucleation and growth kinetics, which is still not well understood. The recent development of in situ high energy synchrotron X-ray techniques offers an excellent opportunity to quantitatively monitor the growth trajectories of colloidal nanoparticles in real time under real reaction conditions. The time-resolved, quantitative data of the growing colloidal nanoparticles are unique to reveal the mechanism of nanoparticle formation and determine the corresponding intrinsic kinetic parameters. This review discusses the kinetics of major steps of forming colloidal nanoparticles and the capability of in situ synchrotron X-ray techniques in studying the corresponding kinetics.

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.

Controlling the properties of TiO2 nanoparticles generated by nanosecond laser ablation in liquid solution

Laser ablation of titanium target in distilled water for synthesis of colloidal nanoparticles is studied both experimentally and theoretically. The effects of laser parameters such as wavelength, pulse energy, fluence and shot numbers on the ablation rate and size properties of colloidal nanoparticles are investigated. The experimental approach addresses the interesting issue for finding the optimal main experimental parameters of laser ablation. The theoretical thermal model of nanosecond pulsed laser ablation is developed to visualize the evolution of temperature distributions and ablation depth. The simulation result of ablation depth has been compared with the experimental result obtained by Nd:YAG laser, 1064 nm wavelength, 10 ns time duration and 200 µm spot size on the target. This comprehensive model has good agreement with experimental results and it can overcome the limitations of the experimental investigation technique and improves the pulsed laser ablation rate.

Investigating Particle Size Effects in Catalysis by Applying a Size-Controlled and Surfactant-Free Synthesis of Colloidal Nanoparticles in Alkaline Ethylene Glycol: Case Study of the Oxygen Reduction Reaction on Pt

Colloidal platinum nanoparticles are obtained via a surfactant-free polyol process in alkaline ethylene glycol. In this popular synthesis, ethylene glycol functions as solvent and reducing agent. The preparation procedure is known for its reproducibility to obtain 1–2 nm nanoparticles, but at the same time the controlled preparation of larger nanoparticles is challenging. A reliable size control without the use of surfactants is a fundamental yet missing achievement for systematic investigations. In this work it is demonstrated how the molar ratio between NaOH and the platinum precursor determines the final particle size and how this knowledge can be used to prepare and study in a systematic way supported catalysts with defined size and Pt to carbon ratio. Using small-angle X-ray scattering, transmission electron microscopy, infrared spectroscopy, X-ray absorption spectroscopy, pair distribution function, and electrochemical analysis it is shown that when the NaOH/Pt molar ratio is changed from 25 to 3 th...

119Sn Mössbauer spectroscopy of the time-resolved evolution of SnCl3− ligand structure on the surface of growing platinum nanoparticles

The importance of stabilizing ligands cannot be understated for the colloidal synthesis of nanoparticles as well as their dispersion and assembly into macro-structures such as electrodes. We have recently demonstrated a novel all-inorganic ligand approach to Pt nanoparticle synthesis where surface-adsorbed Sn serves as both reducing agent and stabilizing ligand, producing remarkably monodispersed nanoparticles. By eliminating the need to remove organic surfactants prior to nanoparticle incorporation into electrodes, we were able to use electrostatic assembly to achieve well-defined nanoparticle dispersions in contrast to the aggregated structures common in the field. The approach has allowed us to elucidate the nature of structure sensitivity for electrocatalytic oxygen reduction reaction in acidic and alkaline media. In this paper, we provide a detailed investigation of the evolution of surface-adsorbed Sn-Pt ligand interaction during Pt nanoparticle growth. We show that surface adsorbed SnCl3− exists as pyramidally coordinated to the Pt nanoparticle through Sn-Pt bond formation, resulting in a distorted tetrahedrally coordinated Sn-moiety. Furthermore, we show the shift in the bond charge distribution as the Pt is reduced from its initial Pt2+ state to its metallic state. Direct evidence for the distorted tetrahedral coordination of Pt-SnCl3− and the shift in Sn-Pt bond charge during nanoparticle growth emerges from the 119Sn Mossbauer quadrupole splitting (QS) and Isomer-shift (IS) respectively. Evolution of the structure and chemistry of inorganic complexes during nanoparticle growth has never before been demonstrated and our work is the first to identify the strength of the Sn-Pt interaction in these systems. Such an understanding of nanoparticle surface chemistry will permit extension of this technique to other metals and macro-structures.

Colloidal quasicrystal for photonics

In this work a method of the laser synthesis of colloidal nanoparticles and the formation of liquid photonic crystals are discussed. Optical properties of the systems depending on the particle concentration, its sizes and shapes were determined.

Matrix Sputtering Method: A Novel Physical Approach for Photoluminescent Noble Metal Nanoclusters.

Noble metal nanoclusters are believed to be the transition between single metal atoms, which show distinct optical properties, and metal nanoparticles, which show characteristic plasmon absorbance. The interesting properties of these materials emerge when the particle size is well below 2 nm, such as photoluminescence, which has potential application particularly in biomedical fields. These photoluminescent ultrasmall nanoclusters are typically produced by chemical reduction, which limits their practical application because of the inherent toxicity of the reagents used in this method. Thus, alternative strategies are sought, particularly in terms of physical approaches, which are known as "greener alternatives," to produce high-purity materials at high yields. Thus, a new approach using the sputtering technique was developed. This method was initially used to produce thin films using solid substrates; now it can be applied even with liquid substrates such as ionic liquids or polyethylene glycol as long as these liquids have a low vapor pressure. This revolutionary development has opened up new areas of research, particularly for the synthesis of colloidal nanoparticles with dimensions below 10 nm. We are among the first to apply the sputtering technique to the physical synthesis of photoluminescent noble metal nanoclusters. Although typical sputtering systems have relied on the effect of surface composition and viscosity of the liquid matrix on controlling particle diameters, which only resulted in diameters ca. 3-10 nm, that were all plasmonic, our new approach introduced thiol molecules as stabilizers inspired from chemical methods. In the chemical syntheses of metal nanoparticles, controlling the concentration ratio between metal ions and stabilizing reagents is a possible means of systematic size control. However, it was not clear whether this would be applicable in a sputtering system. Our latest results showed that we were able to generically produce a variety of photoluminescent monometallic nanoclusters of Au, Ag, and Cu, all of which showed stable emission in both solution and solid form via our matrix sputtering method with the induction of cationic-, neutral-, and anionic-charged thiol ligands. We also succeeded in synthesizing photoluminescent bimetallic Au-Ag nanoclusters that showed tunable emission within the UV-NIR region by controlling the composition of the atomic ratio by a double-target sputtering technique. Most importantly, we have revealed the formation mechanism of these unique photoluminescent nanoclusters by sputtering, which had relatively larger diameters (ca. 1-3 nm) as determined using TEM and stronger emission quantum yield (max. 16.1%) as compared to typical photoluminescent nanoclusters prepared by chemical means. We believe the high tunability of sputtering systems presented here has significant advantages for creating novel photoluminescent nanoclusters as a complementary strategy to common chemical methods. This Account highlights our journey toward understanding the photophysical properties and formation mechanism of photoluminescent noble metal nanoclusters via the sputtering method, a novel strategy that will contribute widely to the body of scientific knowledge of metal nanoparticles and nanoclusters.

Tunable SERS Platforms from Small Nanoparticle 3D Superlattices: A Comparison between Gold, Silver, and Copper.

Herein we present new substrates for surface-enhanced Raman spectroscopy (SERS). The synthesis of colloidal nanoparticles through an organometallic route allowed us to obtain gold, silver, or copper nanoparticles with well-controlled shapes and sizes (5-12 nm in diameter). The organization of these nanoparticles into large-scale 3D superlattices produces a very large number of "hot spots" at the origin of the signal enhancement. Each superlattice was studied individually to correlate its optical and SERS properties to the thickness, the nanoparticle sizes, and the interparticle distance. This experimental and theoretical study provides insights for the optimization and tuning of the SERS activity. Indeed, significant SERS amplification could be observed regardless of the nature of the metal. In addition, the SERS signal was homogeneous at the surface of the superlattices, which opens the route for a new approach in analytical SERS detection.

From Colloidal Monodisperse Nickel Nanoparticles to Well-Defined Ni/Al2O3 Model Catalysts.

In the past few decades, advances in colloidal nanoparticle synthesis have created new possibilities for the preparation of supported model catalysts. However, effective removal of surfactants is a prerequisite to evaluate the catalytic properties of these catalysts in any reaction of interest. Here we report on the colloidal preparation of surfactant-free Ni/Al2O3 model catalysts. Monodisperse Ni nanoparticles (NPs) with mean particle size ranging from 4 to 9 nm were synthesized via thermal decomposition of a zerovalent precursor in the presence of oleic acid. Five weight percent Ni/Al2O3 catalysts were produced by direct deposition of the presynthesized NPs on an alumina support, followed by thermal activation (oxidation-reduction cycle) for complete surfactant removal and surface cleaning. Structural and morphological characteristics of the nanoscale catalysts are described in detail following the propagation of the bulk and surface Ni species at the different treatment stages. Powder X-ray diffraction, electron microscopy, and temperature-programmed reduction experiments as well as infrared spectroscopy of CO adsorption and magnetic measurements were conducted. The applied thermal treatments are proven to be fully adequate for complete surfactant removal while preserving the metal particle size and the size distribution at the level attained by the colloidal synthesis. Compared with standard impregnated Ni/Al2O3 catalysts, the current model materials display narrowed Ni particle size distributions and increased reducibility with a higher fraction of the metallic nickel atoms exposed at the catalyst surface.

In situ oxidation and reduction of triangular nickel nanoplates via environmental transmission electron microscopy.

Understanding the oxidation and reduction mechanisms of transition metals, such as nickel (Ni), is important for their use in industrial applications of catalysis. A powerful technique for investigating the redox reactive species is in situ environmental transmission electron microscopy (ETEM), where oxidation and reduction can be tracked in real time. One particular difficulty in understanding the underlying reactions is understanding the underlying morphology of the starting structure in a reaction, in particular the defects contained in the material, and the exposed surface facets. Here-in, we use a colloidal nanoparticle synthesis in a continuous flow reactor to form nanoplates of nickel coated with oleylamine as a capping agent. We utilise an in situ heating procedure at 300 °C in vacuum to remove the oleylamine ligands, and then oxidise the Ni nanoparticles at 25 °C with 2 Pa oxygen, and follow the nanoparticles initial oxidation. After that, the nanoparticles are oxidised at 200 and 300 °C, making the size of the oxide shell increase to ∼4 nm. The oxide shell could be reduced under 2 Pa hydrogen at 500 °C to its initial size of ∼1 nm. High temperature oxidation encouraged the nanoparticles to form pure NiO nanoparticles, which occurred via the Kirkendall effect leading to hollowing and void formation.

Synthesis of Cesium Lead Halide Perovskite Quantum Dots

Synthesis of quantum dots is a valuable experiment for demonstration and discussion of quantum phenomena in undergraduate chemistry curricula. Recently, a new class of all-inorganic perovskite quantum dots (QDs) with a formula of CsPbX3 (X = Cl, Br, I) was presented and attracted tremendous attention. Here we adapt the synthesis of CsPbX3 QDs for implementation in inorganic chemistry laboratory class. Perovskite QDs have a number of advantages: they exhibit bright photoluminescence in the visible range of spectrum with a narrow bandwidth, and their emission wavelength can be changed by tuning both size and composition of nanoparticles. The described experiment provides a discussion point on many important concepts of inorganic chemistry, materials science, and nanotechnology, such as colloidal synthesis of nanoparticles, perovskite crystal structure, quantum size effect, as well as photovoltaics and renewable energy.

GaNO colloidal nanoparticles synthesis by nanosecond pulsed laser ablation: Laser fluence dependent optical absorption and structural properties

Colloidal GaN nanoparticles were synthesized in distilled water by pulsed laser ablation (PLA) method. Optical and structural analysis were performed on samples generated under different laser fluence by using ultraviolet–visible (UV–vis) absorption spectrophotometer, X-ray diffractometer (XRD) and Tunneling Electron Microscope (TEM) technique. The mean size and size distribution of the nanoparticles were investigated using image processing technique of collected TEM images, in addition to XRD patterns. It is shown that laser fluence has a significant effect on nanoparticles size properties. Also, it is proven that the ablation process affects the nanoparticles size and size distribution. The results show that higher laser fluence produces larger mean size of nanoparticles with a broader size distribution.