Controlling the size of Pt nanoparticles with a cationic surfactant, CnTABr

CrystEngComm ◽  
2018 ◽  
Vol 20 (14) ◽  
pp. 2010-2015 ◽  
Author(s):  
Jongsu Seo ◽  
Siwon Lee ◽  
Bonjae Koo ◽  
WooChul Jung
Keyword(s):  
Cationic Surfactant ◽  
Pt Nanoparticles ◽  
Particle Growth ◽  
Colloidal Synthesis ◽  
Chemical Affinity ◽  
Organic Complex ◽  
Wide Range ◽  
Chain Lengths

We report how the size of Pt nanoparticles varies by using a wide range of chain lengths and concentrations of CnTABr, a cationic surfactant, in aqueous-based colloidal synthesis and confirm that the chemical affinity between the organic complex formed in the solution and the aggregate of the surfactant is an important factor for Pt particle growth.

scholarly journals Moisture-assisted Near-UV Emission Enhancement of Lead-free Cs4CuIn2Cl12 Double Perovskite Nanocrystals

2021 ◽  
Author(s):  
Maning Liu ◽  
Sri Kasi Matta ◽  
Anastasia Matuhina ◽  
G. Krishnamurthy Grandhi ◽  
Harri Ali-Löytty ◽  
...  
Keyword(s):  
Double Perovskite ◽  
Lead Free ◽  
Colloidal Synthesis ◽  
Morphological Transformation ◽  
Perovskite Nanocrystals ◽  
Uv Emission ◽  
Radiative Transitions ◽  
Emission Enhancement ◽  
Wide Range ◽  
Halide Perovskite

Lead-based halide perovskite nanocrystals (NCs) are recognized as emerging emissive materials with superior photoluminescence (PL) properties. However, the toxicity of lead and the swift chemical decomposition under atmospheric moisture severely hinder their commercialization process. Herein, we report the first colloidal synthesis of lead-free Cs4CuIn2Cl12 layered double perovskite NCs via a facile moisture-assisted hot-injection method stemming from relatively nontoxic precursors. While moisture is typically detrimental to NC synthesis, we demonstrate that the presence of water molecules in Cs4CuIn2Cl12 synthesis enhances the PL quantum yield (mainly in the near-UV range), induces a morphological transformation from 3D nanocubes to 2D nanoplatelets, and converts the dark transitions to radiative transitions for the observed self-trapped excitons relaxation. This work paves the way for further studies on the moisture-assisted synthesis of novel lead-free halide perovskite NCs for a wide range of applications.

scholarly journals Exploring New Synthetic Strategies for the Production of Advanced Complex Inorganic Nanocrystals

2015 ◽  
Vol 229 (1-2) ◽  
Author(s):  
Neus G. Bastús ◽  
Edgar Gonzalez ◽  
Joan Esteve ◽  
Jordi Piella ◽  
Javier Patarroyo ◽  
...  
Keyword(s):  
Materials Science ◽  
Chemical Properties ◽  
Synthetic Methods ◽  
Colloidal Synthesis ◽  
Hollow Structures ◽  
Physico Chemical ◽  
Composition And Structure ◽  
Wide Range ◽  
Potential Applicability ◽  
New Generation

AbstractThe design of new protocols for the colloidal synthesis of complex nanocrystals (NCs) with advanced functionalities, comprising both hybrid and hollow structures, and the study of their fundamental properties is of paramount importance for the development of a new generation of nanostructured materials. The possibility of tailoring the dimensional regime of NCs, along with its composition and structure, represents a landmark achievement in the control of their unique physico-chemical properties. These properties, alongside with the ability to cheaply produce high quality NCs in fairly large amounts by wet-chemistry techniques, leads to their potential applicability from materials science to nanomedicine. Within this context, this review is focused on describing a successful framework for designing synthetic strategies for the production of advanced complex NCs, integrating the development of new synthetic methods with its structural characterization, monitoring of their properties, and study of its reactivity. As a result, it is expected to provide new routes to produce robust and easy-to-process NCs in a wide range of sizes, shapes and configurations that can be explored to achieve the combination of all degrees of control, aiming to produce a complete and diverse library of material combinations that will expand its applicability in a wide diversity of fields.

scholarly journals Rapid growth of organic aerosol nanoparticles over a wide tropospheric temperature range

2018 ◽  
Vol 115 (37) ◽  
pp. 9122-9127 ◽  
Author(s):  
Dominik Stolzenburg ◽  
Lukas Fischer ◽  
Alexander L. Vogel ◽  
Martin Heinritzi ◽  
Meredith Schervish ◽  
...  
Keyword(s):  
Growth Rates ◽  
Rapid Growth ◽  
Aerosol Particles ◽  
Particle Growth ◽  
Molecular Cluster ◽  
Tropospheric Temperature ◽  
Initial Growth ◽  
European Organization ◽  
Cold Temperatures ◽  
Wide Range

Nucleation and growth of aerosol particles from atmospheric vapors constitutes a major source of global cloud condensation nuclei (CCN). The fraction of newly formed particles that reaches CCN sizes is highly sensitive to particle growth rates, especially for particle sizes <10 nm, where coagulation losses to larger aerosol particles are greatest. Recent results show that some oxidation products from biogenic volatile organic compounds are major contributors to particle formation and initial growth. However, whether oxidized organics contribute to particle growth over the broad span of tropospheric temperatures remains an open question, and quantitative mass balance for organic growth has yet to be demonstrated at any temperature. Here, in experiments performed under atmospheric conditions in the Cosmics Leaving Outdoor Droplets (CLOUD) chamber at the European Organization for Nuclear Research (CERN), we show that rapid growth of organic particles occurs over the range from −25 °C to 25 °C. The lower extent of autoxidation at reduced temperatures is compensated by the decreased volatility of all oxidized molecules. This is confirmed by particle-phase composition measurements, showing enhanced uptake of relatively less oxygenated products at cold temperatures. We can reproduce the measured growth rates using an aerosol growth model based entirely on the experimentally measured gas-phase spectra of oxidized organic molecules obtained from two complementary mass spectrometers. We show that the growth rates are sensitive to particle curvature, explaining widespread atmospheric observations that particle growth rates increase in the single-digit-nanometer size range. Our results demonstrate that organic vapors can contribute to particle growth over a wide range of tropospheric temperatures from molecular cluster sizes onward.

A universal approach to the preparation of colloidal mesoporous platinum nanoparticles with controlled particle sizes in a wide range from 20 nm to 200 nm

2014 ◽  
Vol 16 (19) ◽  
pp. 8787-8790 ◽  
Author(s):  
Cuiling Li ◽  
Masataka Imura ◽  
Yusuke Yamauchi
Keyword(s):  
Platinum Nanoparticles ◽  
Surfactant Concentration ◽  
Pt Nanoparticles ◽  
Particle Sizes ◽  
Universal Method ◽  
Wide Range ◽  
Universal Approach ◽  
20 Nm ◽  
Mesoporous Platinum

We report a universal method for the preparation of mesoporous Pt nanoparticles with tunable particle sizes by changing the surfactant concentration.

scholarly journals Vapor-Phase Furfural Decarbonylation over a High-Performance Catalyst of 1%Pt/SBA-15

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1304
Author(s):  
Qiang Yuan ◽  
Jifeng Pang ◽  
Wenguang Yu ◽  
Mingyuan Zheng
Keyword(s):  
High Performance ◽  
Catalyst Support ◽  
Pt Nanoparticles ◽  
Space Velocity ◽  
Acid Sites ◽  
Pt Catalyst ◽  
Reaction Conditions ◽  
Weight Hourly Space Velocity ◽  
Wide Range ◽  
Superior Property

A high-performance Pt catalyst supported on SBA-15 was developed for furfural decarbonylation. Compared to Pt catalysts loaded on microporous DeAl-Hbeta zeolite and hierarchical micro-mesoporous MFI nanosheet (NS) materials, the 1%Pt/SBA-15 catalyst afforded notably higher activity, furan selectivity and stability owing to the negligible acid sites and proper mesopores on the SBA-15 support. Among a set of 1%Pt/SBA-15 catalysts bearing Pt nanoparticles (NPs) with sizes of 2.4–4.3 nm, the catalyst with 3.7 nm Pt NPs afforded the highest furan selectivity. Over the optimal catalyst, 88.6% furan selectivity and ca. 90% furfural conversion were obtained at 573 K and a high weight hourly space velocity (WHSV) of 16.5 h−1. Moreover, the reaction temperatures at 440–573 K and the ratios of H2 to furfural at 0.79–9.44 did not affect the reaction selectivity notably, showing that the reaction over 1%Pt/SBA-15 can be conducted over a wide range of conditions. The catalyst was stable under the harsh reaction conditions and lasted for 90 h without significant deactivation, demonstrating the superior property of SBA-15 as a catalyst support for furfural decarbonylation.

Aluminoborosilicate waste glass dissolution under alkaline conditions at 40°C: implications for a chemical affinity-based rate equation

2008 ◽  
Vol 5 (1) ◽  
pp. 73 ◽  
Author(s):  
E. M. Pierce ◽  
E. L. Richards ◽  
A. M. Davis ◽  
L. R. Reed ◽  
E. A. Rodriguez
Keyword(s):  
Low Flow ◽  
Chemical Affinity ◽  
Solution Composition ◽  
Dissolution Rates ◽  
Residual Rate ◽  
Glass Dissolution ◽  
Daunting Task ◽  
Wide Range ◽  
The Impact ◽  
Low Activity

Environmental context. The production of nuclear materials has generated a very large amount of highly radioactive wastes that need to be disposed of in a manner that will keep them from posing a danger for millions of years until the radioactivity decays. The process being considered for this daunting task is to contain the wastes in glass. Although studies with ancient and natural glass suggest the weathering of glass is slow, experiments are being conducted to determine the impact of this material on the natural environment and attempt to predict its long-term behaviour. The present paper briefly discusses three models that are being considered for implementing this process and the one that appears to hold the most promise. Abstract. Single-pass flow-through experiments were conducted with aluminoborosilicate waste glasses to evaluate how changes in solution composition affect the dissolution rate (r) at 40°C and pH (23°C) = 9.0. The three prototypic low-activity waste (LAW) glasses, LAWE-1A, -95A and -290A, used in these experiments span a wide range covering the expected processing composition of candidate immobilised low-activity waste (ILAW) glasses. Results suggest incongruent release of Al, B, Na, and Si at low flow-rate (q) to sample surface area (S), in units of (m s–1), (log10(q/S) < –8.9) whereas congruent release is observed at high q/S (log10(q/S) > –7.9). Dissolution rates increase from log10(q/S) ≈ –9.3 to –8.0 and then become constant at log10(q/S) > –7.9. Forward (maximum) dissolution rates, based on B release, are the same irrespective of glass composition, evident by the dissolution rates being within the experimental error of one another (r1A = 0.0301 ± 0.0153 g m–2 day–1, r95A = 0.0248 ± 0.0125 g m–2 day–1, and r290A = 0.0389 ± 0.0197 g m–2 day–1). The results also illustrate that as the activity of SiO2(aq) increases, the rate of glass dissolution decreases to a residual rate. The pseudo-equilibrium constant, Kg, (log10(Kg) = –3.7) predicted with these results is slightly lower than the K for chalcedony (log10(K) = –3.48) at 40°C. Finally, these results support the use of a chemical affinity-based rate law to describe glass dissolution as a function of solution composition.

scholarly journals Using measurements of the aerosol charging state in determination of the particle growth rate and the proportion of ion-induced nucleation

2013 ◽  
Vol 13 (1) ◽  
pp. 463-486 ◽  
Author(s):  
J. Leppä ◽  
S. Gagné ◽  
L. Laakso ◽  
H. E. Manninen ◽  
K. E. J. Lehtinen ◽  
...  
Keyword(s):  
Growth Rate ◽  
Data Analysis ◽  
Charged Particles ◽  
Particle Diameter ◽  
Particle Growth ◽  
Assessment Procedure ◽  
Actual Measurement ◽  
Analysis Methods ◽  
Wide Range ◽  
Data Analysis Methods

Abstract. The fraction of charged nucleation mode particles as a function of particle diameter depends on the particle growth rate and the proportion of particles formed via ion-induced nucleation. In this study we have tested the applicability of recent data analysis methods to determine the growth rate and the proportion of ion-induced nucleation from the measured charged fractions. For this purpose we have conducted a series of aerosol dynamic simulations covering a wide range of atmospheric conditions. The growth rate and initial fraction of charged particles were estimated from simulated data using these methods and compared with the values obtained directly from the simulations. We found that the data analysis methods used in this study should not be used when the nuclei growth rate is less than ~3 nm h−1, or when charged particles grow much more rapidly than neutral ones. Furthermore, we found that the difference in removal rates of neutral and charged particles should be taken into account when estimating the proportion of ion-induced nucleation. Neglecting the higher removal rate of charged particles compared with that of neutral ones could result in an underestimation of the proportion of ion-induced nucleation by up to a factor of 2. This underestimation is further increased if charged particles grow more rapidly than neutral ones. We also provided a simple way of assessing whether these methods are suitable for analyzing data measured under specific conditions. The assessment procedure was illustrated using a few examples of actual measurement sites with a more detailed examination of the typical conditions observed at the SMEAR II station in Hyytiälä, Finland.

scholarly journals Development and Application of a Wide Dynamic Range and High Resolution Atmospheric Aerosol Water-Based Supersaturation Condensation Growth Measurement System

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 558
Author(s):  
Jiejie Bian ◽  
Huaqiao Gui ◽  
Xiuli Wei ◽  
Tongzhu Yu ◽  
Zhibo Xie ◽  
...  
Keyword(s):  
Measurement System ◽  
Atmospheric Aerosol ◽  
Ultrafine Particles ◽  
Dynamic Range ◽  
Growth Control ◽  
Particle Growth ◽  
Hygroscopic Growth ◽  
Growth Measurement ◽  
Wide Range ◽  
Condensation Growth

The supersaturated condensation of atmospheric aerosol is important in the study of mechanisms of cloud condensation and even heavy air pollution. The existing technology cannot realize accurate dynamic control of wide range supersaturation, so it is difficult to study condensation growth characteristics of nanoparticles through different levels of supersaturation. Here, a supersaturated condensation growth measurement system with three-stage microscope pipes was developed. The resolution of supersaturated condensation system is 0.14, within the range of 0.92 to 2.33 after calibration. Stabilization time is only about 80 s for saturation range 0.92–1.01, which helps to control saturation rapidly, and the control deviation of saturation is no more than 0.06. Measurement of different supersaturated condensation growth control conditions showed that, the particle size increased significantly compared with hygroscopic growth at high humidity. For single-component particles, the increase in size increased to a similar size at the same saturation, with a difference within 7.4%. The increase in size for ammonium sulfate (AS) increased by 13.4–30.2% relative to that of glucose. For the mixed-component, the increase in size decreased about 15.9–25.0% with the increase of the glucose. Because the glucose coating on the surface of AS have hindered particle growth. This also shows that atmospheric ultrafine particles, especially inorganic salt particles, will rapidly grow into larger particles under supersaturated conditions such as increased environmental humidity, thus having some impact on environmental pollution and climate change.

Intestinal absorption of 25-hydroxyvitamin D3 in unanesthetized rat.

1979 ◽  
Vol 236 (4) ◽  
pp. E441 ◽  
Author(s):  
D Hollander ◽  
E Rim ◽  
D Morgan
Keyword(s):  
Fatty Acids ◽  
Bile Acid ◽  
Acid Concentration ◽  
Diffusion Mechanism ◽  
Water Layer ◽  
Bile Acid Concentration ◽  
Unstirred Water Layer ◽  
Wide Range ◽  
Bile Drainage ◽  
Chain Lengths

We investigated the mechanism and characteristics of 25-hydroxyvitamin D3 (25-OH-D3) absorption in the unanesthetized rat by using a single-pass intestinal perfusion technique. The rate of 25-OH-D3 absorption remained linear for a wide range of concentrations (2-900 nM). Absorption rate of 25-OH-D3 increased as the pH, the bile acid concentration, and thickness of the unstirred water layer were decreased. Absorption did not change after the additions of fatty acids of varied chain lengths and degrees of saturation. In rats with lymph and bile fistulas, 18.5% and 16.3% of the infused radio-activity appeared in the lymph and bile drainage, respectively. These experiments indicate that 25-OH-D3 is absorbed by a passive diffusion mechanism that is influenced by the intestinal pH, bile acid concentration, and thickness of the unstirred water layer, but not by the presence of fatty acids. Approximately equal fractions of the infused hydroxylated vitamin are recovered from the lymphatic and biliary fluids.

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