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Aloraini S, Mathias M, Crone J, Bryce K, Yu M, Kirk RA, Ahmad MZ, Asuquo ED, Rico-Martínez S, Volkov AV, Foster AB, Budd PM. Crosslinking of Branched PIM-1 and PIM-Py Membranes for Recovery of Toluene from Dimethyl Sulfoxide by Pervaporation. ACS APPLIED POLYMER MATERIALS 2023; 5:1145-1158. [PMID: 36817336 PMCID: PMC9926464 DOI: 10.1021/acsapm.2c01600] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 12/22/2022] [Indexed: 06/18/2023]
Abstract
Branched forms of the archetypal polymer of intrinsic microporosity PIM-1 and the pyridinecarbonitrile-containing PIM-Py may be crosslinked under ambient conditions by palladium(II) acetate. Branched PIM-1 can arise in polymerizations of 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane with tetrafluoroterephthalonitrile conducted at a high set temperature (160 °C) under conditions, such as high dilution, that lead to a lower-temperature profile over the course of the reaction. Membranes of PIM-1 and PIM-Py crosslinked with palladium acetate are sufficiently stable in organic solvents for use in the recovery of toluene from its mixture with dimethyl sulfoxide (DMSO) by pervaporation at 65 °C. With both PIM-1 and PIM-Py membranes, pervaporation gives high toluene/DMSO separation factors (around 10 with a 77 vol % toluene feed). Detailed analysis shows that the membranes themselves are slightly selective for DMSO and it is the high driving force for toluene evaporation that drives the separation.
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Affiliation(s)
- Sulaiman Aloraini
- Department
of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, United Kingdom
- Department
of Chemistry, College of Science and Arts, Qassim University, Ar Rass52571, Saudi Arabia
| | - Michael Mathias
- Department
of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, United Kingdom
| | - Jessica Crone
- Department
of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, United Kingdom
| | - Kurtis Bryce
- Department
of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, United Kingdom
| | - Ming Yu
- Department
of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, United Kingdom
- Department
of Chemical Engineering, The University
of Melbourne, Melbourne, VIC3010, Australia
| | - Richard A. Kirk
- Department
of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, United Kingdom
| | - Mohd Zamidi Ahmad
- Department
of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, United Kingdom
| | - Edidiong D. Asuquo
- Department
of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, United Kingdom
| | | | - Alexey V. Volkov
- A.
V. Topchiev Institute of Petrochemical Synthesis, 29 Leninsky Avenue, Moscow119991, Russian
Federation
| | - Andrew B. Foster
- Department
of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, United Kingdom
| | - Peter M. Budd
- Department
of Chemistry, University of Manchester, Oxford Road, ManchesterM13 9PL, United Kingdom
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2
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Ricciardulli T, Adams JS, DeRidder M, van Bavel AP, Karim AM, Flaherty DW. H2O-assisted O2 reduction by H2 on Pt and PtAu bimetallic nanoparticles: Influences of composition and reactant coverages on kinetic regimes, rates, and selectivities. J Catal 2021. [DOI: 10.1016/j.jcat.2021.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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3
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Yu X, Chen X, Meng W, Zhu M. Research progress on supported solid superbase and its catalytic application. CHEMICAL PAPERS 2021. [DOI: 10.1007/s11696-021-01669-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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4
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Zakrzewska J, Uznanski P. Synthesis and characterization of bis(amine)palladium(II) carboxylate complexes as precursors of palladium nanoparticles. Dalton Trans 2021; 50:6933-6948. [PMID: 33928977 DOI: 10.1039/d1dt00638j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The synthesis and characterization of the adducts of n-alkyl amine and palladium n-alkyl carboxylate, [Pd(R2NH2)2(R1COO)2] (R1 = 1, 7, and 11; R2 = 8, 12, and 16), as precursors for the synthesis of palladium nanoparticles (PdNPs) was carried out via differential scanning calorimetry, FT-IR, Raman and UV-Vis spectroscopy, NMR spectroscopy (1H, 13C pulsed field gradient spin-echo (PGSE), and 13C CP-MAS), and powder X-ray diffraction. Pd n-alkyl carboxylates were obtained by a ligand exchange reaction from palladium acetate and the appropriate aliphatic carboxylic acid. It is proposed that carboxyl moieties in the presence of amine ligands are bound to palladium ions via monodentate bonding as opposed to bridging bidentate coordination of pure palladium carboxylate which exists in the form of polymer aggregates. All the studied palladium carboxylate/amine complexes form bilayer lamellar structures and exhibit first-order melting transitions. The evidence presented in this study shows that the phase behavior of bivalent metal carboxylates is mainly controlled by the type of coordination of carboxylate head groups. For n-alkyl carboxylates, linear chain type aggregates replace the trimeric units of Pd acetate. In solution, in the presence of amine, palladium salt aggregates disintegrate and the Pd complex is isolated and stabilized by amine molecules. Using bis(amine) palladium carboxylate adducts as precursors, palladium nanoparticles were fabricated. During high temperature thermolysis, the bis(amine) Pd carboxylate complex decomposes to form small sized Pd nanoparticles. Combining NMR techniques with FTIR spectroscopy, it was possible to follow an original stabilization mechanism. PdNPs are stabilized by weakly interacting long chain aliphatic amide and carboxylic acid derived from the palladium precursor.
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Affiliation(s)
- Joanna Zakrzewska
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland.
| | - Pawel Uznanski
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland.
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5
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Ricciardulli T, Gorthy S, Adams JS, Thompson C, Karim AM, Neurock M, Flaherty DW. Effect of Pd Coordination and Isolation on the Catalytic Reduction of O 2 to H 2O 2 over PdAu Bimetallic Nanoparticles. J Am Chem Soc 2021; 143:5445-5464. [PMID: 33818086 DOI: 10.1021/jacs.1c00539] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The direct synthesis of hydrogen peroxide (H2 + O2 → H2O2) may enable low-cost H2O2 production and reduce environmental impacts of chemical oxidations. Here, we synthesize a series of Pd1Aux nanoparticles (where 0 ≤ x ≤ 220, ∼10 nm) and show that, in pure water solvent, H2O2 selectivity increases with the Au to Pd ratio and approaches 100% for Pd1Au220. Analysis of in situ XAS and ex situ FTIR of adsorbed 12CO and 13CO show that materials with Au to Pd ratios of ∼40 and greater expose only monomeric Pd species during catalysis and that the average distance between Pd monomers increases with further dilution. Ab initio quantum chemical simulations and experimental rate measurements indicate that both H2O2 and H2O form by reduction of a common OOH* intermediate by proton-electron transfer steps mediated by water molecules over Pd and Pd1Aux nanoparticles. Measured apparent activation enthalpies and calculated activation barriers for H2O2 and H2O formation both increase as Pd is diluted by Au, even beyond the complete loss of Pd-Pd coordination. These effects impact H2O formation more significantly, indicating preferential destabilization of transition states that cleave O-O bonds reflected by increasing H2O2 selectivities (19% on Pd; 95% on PdAu220) but with only a 3-fold reduction in H2O2 formation rates. The data imply that the transition states for H2O2 and H2O formation pathways differ in their coordination to the metal surface, and such differences in site requirements require that we consider second coordination shells during the design of bimetallic catalysts.
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Affiliation(s)
- Tomas Ricciardulli
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Sahithi Gorthy
- Department of Chemical and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jason S Adams
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Coogan Thompson
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, United States
| | - Ayman M Karim
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, United States
| | - Matthew Neurock
- Department of Chemical and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - David W Flaherty
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
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6
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Liu Q, Yin J, Zhang BB, Chen JK, Zhou Y, Zhang LM, Wang LM, Zhao Q, Hou J, Shu J, Song B, Shirahata N, Bakr OM, Mohammed OF, Sun HT. Theory-Guided Synthesis of Highly Luminescent Colloidal Cesium Tin Halide Perovskite Nanocrystals. J Am Chem Soc 2021; 143:5470-5480. [PMID: 33794093 DOI: 10.1021/jacs.1c01049] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The synthesis of highly luminescent colloidal CsSnX3 (X = halogen) perovskite nanocrystals (NCs) remains a long-standing challenge due to the lack of a fundamental understanding of how to rationally suppress the formation of structural defects that significantly influence the radiative carrier recombination processes. Here, we develop a theory-guided, general synthetic concept for highly luminescent CsSnX3 NCs. Guided by density functional theory calculations and molecular dynamics simulations, we predict that, although there is an opposing trend in the chemical potential-dependent formation energies of various defects, highly luminescent CsSnI3 NCs with narrow emission could be obtained through decreasing the density of tin vacancies. We then develop a colloidal synthesis strategy that allows for rational fine-tuning of the reactant ratio in a wide range but still leads to the formation of CsSnI3 NCs. By judiciously adopting a tin-rich reaction condition, we obtain narrow-band-emissive CsSnI3 NCs with a record emission quantum yield of 18.4%, which is over 50 times larger than those previously reported. Systematic surface-state characterizations reveal that these NCs possess a Cs/I-lean surface and are capped with a low density of organic ligands, making them an excellent candidate for optoelectronic devices without any postsynthesis ligand management. We showcase the generalizability of our concept by further demonstrating the synthesis of highly luminescent CsSnI2.5Br0.5 and CsSnI2.25Br0.75 NCs. Our findings not only highlight the value of computation in guiding the synthesis of high-quality colloidal perovskite NCs but also could stimulate intense efforts on tin-based perovskite NCs and accelerate their potential applications in a range of high-performance optoelectronic devices.
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Affiliation(s)
- Qi Liu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Jun Yin
- Advanced Membranes and Porous Materials Center (AMPMC) & KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Bin-Bin Zhang
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047, Japan.,Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0814, Japan
| | - Jia-Kai Chen
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047, Japan.,Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0814, Japan
| | - Yang Zhou
- Advanced Membranes and Porous Materials Center (AMPMC) & KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Lu-Min Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Lu-Ming Wang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Qing Zhao
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047, Japan
| | - Jingshan Hou
- School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418, China
| | - Jie Shu
- Analysis and Testing Center, Soochow University, Jiangsu 215123, China
| | - Bo Song
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Naoto Shirahata
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047, Japan.,Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0814, Japan.,Department of Physics, Chuo University, Tokyo 112-8551, Japan
| | - Osman M Bakr
- Advanced Membranes and Porous Materials Center (AMPMC) & KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Omar F Mohammed
- Advanced Membranes and Porous Materials Center (AMPMC) & KAUST Catalysis Center (KCC), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Hong-Tao Sun
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047, Japan
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7
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Li W, Taylor MG, Bayerl D, Mozaffari S, Dixit M, Ivanov S, Seifert S, Lee B, Shanaiah N, Lu Y, Kovarik L, Mpourmpakis G, Karim AM. Solvent manipulation of the pre-reduction metal-ligand complex and particle-ligand binding for controlled synthesis of Pd nanoparticles. NANOSCALE 2021; 13:206-217. [PMID: 33325939 DOI: 10.1039/d0nr06078j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Understanding how to control the nucleation and growth rates is crucial for designing nanoparticles with specific sizes and shapes. In this study, we show that the nucleation and growth rates are correlated with the thermodynamics of metal-ligand/solvent binding for the pre-reduction complex and the surface of the nanoparticle, respectively. To obtain these correlations, we measured the nucleation and growth rates by in situ small angle X-ray scattering during the synthesis of colloidal Pd nanoparticles in the presence of trioctylphosphine in solvents of varying coordinating ability. The results show that the nucleation rate decreased, while the growth rate increased in the following order, toluene, piperidine, 3,4-lutidine and pyridine, leading to a large increase in the final nanoparticle size (from 1.4 nm in toluene to 5.0 nm in pyridine). Using density functional theory (DFT), complemented by 31P nuclear magnetic resonance and X-ray absorption spectroscopy, we calculated the reduction Gibbs free energies of the solvent-dependent dominant pre-reduction complex and the solvent-nanoparticle binding energy. The results indicate that lower nucleation rates originate from solvent coordination which stabilizes the pre-reduction complex and increases its reduction free energy. At the same time, DFT calculations suggest that the solvent coordination affects the effective capping of the surface where stronger binding solvents slow the nanoparticle growth by lowering the number of active sites (not already bound by trioctylphosphine). The findings represent a promising advancement towards understanding the microscopic connection between the metal-ligand thermodynamic interactions and the kinetics of nucleation and growth to control the size of colloidal metal nanoparticles.
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Affiliation(s)
- Wenhui Li
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA.
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8
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Ecofriendly Synthesis of Silver Nanoparticles Using Aqueous Extracts of Zingiber officinale (Ginger) and Nigella sativa L. Seeds (Black Cumin) and Comparison of Their Antibacterial Potential. SUSTAINABILITY 2020. [DOI: 10.3390/su122410523] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Applications of chemical synthetic methods for the preparation of metal nanoparticles involve toxic reagents, which are hazardous to both humans and the environment. On the other hand, ecofriendly plant-based techniques offer rapid, non-toxic, and suitable alternatives to the traditional methods. Herein, we report an eco-friendly method for the preparation of silver nanoparticles (Ag NPs) using two different aqueous extracts of Zingiber officinale (ginger) and Nigella sativa L. seeds (black cumin). Successful preparation of Ag NPs was confirmed by X-ray diffraction, ultraviolet–visible (UV-Vis) spectroscopy, and energy dispersive spectroscopy (EDX). Transmission electron microscopy (TEM) analysis revealed that Nigella sativa L. seed extract (NSE) produced a smaller size of NPs (~8 nm), whereas the ginger extract (GE) led to the formation of slightly larger Ag NPs (~12 nm). In addition, to study the effect of concentration of the extract on the quality of resulting NPs, two different samples were prepared from each extract by increasing the concentrations of the extracts while using a fixed amount of precursor (AgNO3). In both cases, a high concentration of extract delivered less agglomerated and smaller-sized Ag NPs. Furthermore, the antibacterial properties of as-prepared Ag NPs were tested against different bacterial strains. Notably, despite the slightly better quality of Ag NPs obtained from NSE (NSE-Ag), NPs prepared by using GE (GE-Ag) demonstrated superior antibacterial properties. In case of the plant-extract-based synthesis of nanoparticles, it is widely reported that during the preparation, the residual phytomolecules remain on the surface of resulting NPs as stabilizing agents. Therefore, in this case, the high antibacterial properties of GE-Ag can be attributed to the contributing or synergetic effect of residual phytomolecules of GE extract on the surface of Ag NPs, since the aqueous extract of GE has been known to possess higher intrinsic bactericidal properties when compared to the aqueous NSE extract.
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9
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New (NHC)Pd(II)(PPh3) complexes: synthesis, characterization, crystal structure and its application on Sonogashira and Mizoroki–Heck cross-coupling reactions. CHEMICAL PAPERS 2020. [DOI: 10.1007/s11696-019-00859-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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10
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Thermo-Diffusion and Multislip Effects on MHD Mixed Convection Unsteady Flow of Micropolar Nanofluid over a Shrinking/Stretching Sheet with Radiation in the Presence of Heat Source. Symmetry (Basel) 2019. [DOI: 10.3390/sym12010049] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The main purpose of this study is to investigate the multislip effects on the magneto-hydrodynamic (MHD) mixed convection unsteady flow of micropolar nano-fluids over a stretching/shrinking sheet along with radiation in the presence of a heat source. The consequences of multislip and buoyancy conditions have been integrated. By using the suitable similarity variables are used to solve the governing non-linear partial differential equations into a system of coupled non-linear ordinary differential equations. The transformed equations are solved numerically by using Runge–Kutta fourth-order method with shooting technique. The impacts of the several parameters on the velocity, temperature, micro-rotation, and concentration profiles as well as on the skin friction coefficient, Sherwood number, and Nusselt number are discussed with the help of graphs and tables.
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11
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Fabrication of Fe3O4@SiO2 Nanofluids with High Breakdown Voltage and Low Dielectric Loss. COATINGS 2019. [DOI: 10.3390/coatings9110716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Insulating oil modified by nanoparticle (often called nanofluids) has recently drawn considerable attention, especially concerning the improvement of electrical breakdown and thermal conductivity of the nanofluids. However, traditional insulating nanofluid often tends to high dielectric loss, which accelerates the ageing of nanofluids and limits its application in electrical equipment. In this paper, three core-shell Fe3O4@SiO2 nanoparticles with different SiO2 shell thickness were prepared and subsequently dispersed into insulating oil to achieve nanofluids. The dispersion stability, breakdown voltages and dielectric properties of these nanofluids were comparatively investigated. Experimental results show the alternating current (AC) and positive lightning breakdown voltage of nanofluids increased by 30.5% and 61%, respectively. Moreover, the SiO2 shell thickness of Fe3O4@SiO2 nanoparticle had significant effects on the dielectric loss of nanofluids.
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12
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Mozaffari S, Li W, Dixit M, Seifert S, Lee B, Kovarik L, Mpourmpakis G, Karim AM. The role of nanoparticle size and ligand coverage in size focusing of colloidal metal nanoparticles. NANOSCALE ADVANCES 2019; 1:4052-4066. [PMID: 36132098 PMCID: PMC9417622 DOI: 10.1039/c9na00348g] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/05/2019] [Indexed: 05/10/2023]
Abstract
Controlling the size distribution of nanoparticles is important for many applications and typically involves the use of ligands during synthesis. In this study, we show that the mechanism of size focusing involves a dependence of the growth rate on the size of the nanoparticles and the ligand coverage on the surface of the nanoparticles. To demonstrate these effects, we used in situ small angle X-ray scattering (SAXS) and population balance kinetic modeling (PBM) to investigate the evolution of size distribution during the synthesis of colloidal Pd metal nanoparticles. Despite temporal overlap of nucleation and growth, our in situ SAXS show size focusing of the distribution under different synthetic conditions (different concentrations of metal and ligand as well as solvent type). To understand the mechanism of size focusing using PBM, we systematically studied how the evolution of the nanoparticle size distribution is affected by nucleation rate, and dependence of the growth rate constant on ligand surface coverage, and size of the nanoparticles. We show that continuous nucleation contributes to size defocusing. However, continuous nucleation results in different reaction times for the nanoparticle population leading to time and size-dependent ligand surface coverage. Using density functional theory (DFT) calculations and Brønsted-Evans-Polanyi relations, we show that as the population grows, larger nanoparticles grow more slowly than smaller ones due to lower intrinsic activity and higher ligand coverage on the surface. Therefore, despite continuous nucleation, the faster growth of smaller nanoparticles in the population leads to size focusing. The size focusing behaviour (due to faster growth of smaller nanoparticles) was found to be model independent and similar results were demonstrated under different nucleation and growth pathways (e.g. growth via ion reduction on the surface and/or monomer addition). Our results provide a microscopic connection between kinetics and thermodynamics of nanoparticle growth and metal-ligand binding, and their effect on the size distribution of colloidal nanoparticles.
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Affiliation(s)
- Saeed Mozaffari
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University Blacksburg VA 24060 USA
| | - Wenhui Li
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University Blacksburg VA 24060 USA
| | - Mudit Dixit
- Department of Chemical Engineering, University of Pittsburgh Pittsburgh Pennsylvania 15261 USA
| | - Soenke Seifert
- Advanced Photon Source, Argonne National Laboratory Argonne IL 60439 USA
| | - Byeongdu Lee
- X-ray Science Division, Argonne National Laboratory Argonne IL 60439 USA
| | - Libor Kovarik
- Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory Richland Washington 99352 USA
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh Pittsburgh Pennsylvania 15261 USA
| | - Ayman M Karim
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University Blacksburg VA 24060 USA
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Sabarinath S, Prabha Rajeev S, Rajendra Kumar PK, Prabhakaran Nair K. Development of fully formulated eco-friendly nanolubricant from sesame oil. APPLIED NANOSCIENCE 2019. [DOI: 10.1007/s13204-019-01121-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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14
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Lionetto F, López-Muñoz R, Espinoza-González C, Mis-Fernández R, Rodríguez-Fernández O, Maffezzoli A. A Study on exfoliation of Expanded Graphite Stacks in Candelilla Wax. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E2530. [PMID: 31398950 PMCID: PMC6721147 DOI: 10.3390/ma12162530] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/30/2019] [Accepted: 08/01/2019] [Indexed: 12/14/2022]
Abstract
A novel, green route for pre-exfoliation of graphite based on a biodegradable polymer and high-power ultrasound is presented. Candelilla wax (CW), derived from the leaves of the candelilla plant, has been used for the first time as a natural non aqueous medium to induce the pre-exfoliation of expanded graphite (EG) under ultrasonic irradiation in an economical way. The proposed method uses also D-limonene as a natural organic solvent for reducing viscosity and increasing the affinity between the polar groups of EG and candelilla wax, thus improving the intercalation/exfoliation of EG. The quality of dispersion of the nanofiller in the natural wax matrix has been evaluated using multiple techniques. The addition of EG to wax and use of ultrasonic treatment leads to a reduced crystallinity, probably due to restrictions of the molecular movements, improved thermal stability of wax, and to an increased shear thinning exponent, which are all indicative of a high degree of EG dispersion. The ultrasonic dynamic mechanical results suggest a reduction in the cluster size and a better filler dispersion in the wax matrix promoted by polar or chemical reactions between the CW fractions and the graphite stacks, which was observed by XPS analysis. The results were compared to those obtained with paraffin, a synthetic wax, and confirmed the dispersion improvement obtained by using natural wax as a pre-exfoliating medium.
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Affiliation(s)
- Francesca Lionetto
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, Via per Arnesano, 73100 Lecce, Italy
| | - Roberto López-Muñoz
- Department of Advanced Materials, Research Center for Applied Chemistry (CIQA), Blvd. Enrique Reyna 140, 25294 Saltillo, Mexico
| | - Carlos Espinoza-González
- Department of Advanced Materials, Research Center for Applied Chemistry (CIQA), Blvd. Enrique Reyna 140, 25294 Saltillo, Mexico.
| | - Ricardo Mis-Fernández
- Applied Physics Department, CINVESTAV-IPN, Apdo. Postal 73, 97310 Mérida, Yucatán, Mexico
| | - Oliverio Rodríguez-Fernández
- Department of Advanced Materials, Research Center for Applied Chemistry (CIQA), Blvd. Enrique Reyna 140, 25294 Saltillo, Mexico
| | - Alfonso Maffezzoli
- Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy.
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15
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Performance and Reinforcement Mechanism of Modified Asphalt Binders with Nano-Particles, Whiskers, and Fibers. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9152995] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The asphalt binders could be modified to improve road perfo rmances by using various methods, and the reinforcement mechanisms are obviously different and quietly affect the road performances. According to the composite reinforcement theory, nano-CaCO3 particles, CaCO3 whiskers, and aramid fibers were used as reinforcements to prepare modified asphalt binders, and the conventional technical performances and dynamic shear rheometer (DSR) rheological properties were measured and investigated. In addition, scanning electron microscopy (SEM) was applied to observe the interfaces between reinforcements and asphalt matrixes and the different reinforcement mechanisms were analyzed. The test results showed that the use of nano-CaCO3 particles, CaCO3 whiskers, and aramid fibers can improve the high-temperature stability of modified asphalt binders by different reinforcement mechanisms. The nano-CaCO3 particles were still effective under high-temperature conditions and could last for a long time through the principle of dispersion enhancement. The CaCO3 whiskers segregate easily and cannot be well dispersed in asphalt binders. The aramid fibers played an important role of stress transmission and fiber reinforcement in asphalt binders, and 2 mm-aramid fibers hold the best reinforcement effects. The conclusions can provide a reference for the selection and application of modifiers in the preparation of modified asphalt in laboratory and engineering projects.
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Amidation of fatty acid methyl ester using metal oxides and hydroxides as catalysts. CHEMICAL PAPERS 2019. [DOI: 10.1007/s11696-019-00706-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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