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Pérez-Álvarez J, Tojo C, Buceta D, López-Quintela MA. Tailored surface composition of Au/Pt nanocatalysts synthesized in microemulsions: a simulation study. RSC Adv 2020; 10:42277-42286. [PMID: 35516746 PMCID: PMC9057839 DOI: 10.1039/d0ra08227a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 11/13/2020] [Indexed: 11/21/2022] Open
Abstract
Au/Pt nanoparticles show an optimized catalytic activity when compared with Pt nanoparticles because Pt activity is improved by the presence of Au on the surface. It was checked whether a controllable surface composition can be achieved by the simple strategy of varying the Au : Pt ratio. We present an in-depth kinetic simulation study on the influence of Au : Pt ratio on the formation of Au/Pt nanoparticles synthesized in microemulsions. This study is able to explain the resulting nanoarrangement as a function of kinetic parameters such as Au : Pt ratio and intermicellar exchange rate. The role of the micelles as a dosing pump of the Au precursor explains that a higher Au amount results in a Au reduction which takes place over a longer period of time. It implies that Au is deposited until longer stages of the synthesis, so Au is present at the nanoparticle surface. Micelles as reaction media produce a minor impact on Pt due to its slower reduction. These different kinetic behaviours of Au and Pt give rise to a surface composition which can be tailored by tuning the Au : Pt ratio. Numerical results on surface composition successfully reproduce experimental data and further support the outcomes of the degree of atomic mixing under different Au : Pt ratios. Pure Pt surface at low Au content and mixed surface at high Au content.![]()
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Affiliation(s)
| | - Concha Tojo
- Physical Chemistry Department
- University of Vigo
- Vigo
- Spain
| | - David Buceta
- Laboratorio de Magnetismo y Nanotecnología
- University of Santiago de Compostela
- Santiago de Compostela
- Spain
| | - M. Arturo López-Quintela
- Laboratorio de Magnetismo y Nanotecnología
- University of Santiago de Compostela
- Santiago de Compostela
- Spain
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Tojo C, Buceta D, López-Quintela MA. Bimetallic nanoparticles synthesized in microemulsions: A computer simulation study on relationship between kinetics and metal segregation. J Colloid Interface Sci 2018; 510:152-161. [DOI: 10.1016/j.jcis.2017.09.057] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/13/2017] [Accepted: 09/14/2017] [Indexed: 11/24/2022]
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Affiliation(s)
- Keti Piradashvili
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | | | - Frederik R. Wurm
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Katharina Landfester
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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Moldes ÓA, Astray G, Cid A, Iglesias-Otero MÁ, Morales J, Mejuto JC. Percolation Threshold of AOT Microemulsions with n-Alkyl Acids as Additives Prediction by Means of Artificial Neural Networks. TENSIDE SURFACT DET 2013. [DOI: 10.3139/113.110268] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Different artificial neural networks architectures have been assayed to predict percolation temperature of AOT/iC8/H2O microemulsions in the presence of n-alkyl acids with a chain length between 0 and 24 carbons, using a multilayer perceptron with five easy-acquired entrance variables (number of carbons, log P, length of the hydrocarbon chain, pKa
and acid concentration). The evaluation of the neural networks was carried out by means of RMSE and IDP, resulting that the architecture with better results consists in five input neurons, two middle layers (with five and ten neuron respectively) and one output neuron. Results prove that Artificial Neural Networks are a useful tool elaborating models to predict percolation temperature of microemulsion systems in the presence of additives.
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Affiliation(s)
- Óscar A. Moldes
- Physical-Chemistry Department, Faculty of Sciences, University of Vigo, Ourense, 32004-Ourense, Spain
| | - Gonzalo Astray
- Physical-Chemistry Department, Faculty of Sciences, University of Vigo, Ourense, 32004-Ourense, Spain
- Faculty of Law, International University of La Rioja, 26002-Logroño, Spain
| | - Antonio Cid
- REQUIMTE, Department of Chemistry, FCT-UNL, 2829-516 Monte de Caparica, Portugal
| | - Manuel Á. Iglesias-Otero
- Physical-Chemistry Department, Faculty of Sciences, University of Vigo, Ourense, 32004-Ourense, Spain
| | - Jorge Morales
- Physical-Chemistry Department, Faculty of Sciences, University of Vigo, Ourense, 32004-Ourense, Spain
| | - Juan C. Mejuto
- Physical-Chemistry Department, Faculty of Sciences, University of Vigo, Ourense, 32004-Ourense, Spain
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Andújar-Matalobos M, García-Río L, López-García S, Rodríguez-Dafonte P. Polarity of the interface in ionic liquid in oil microemulsions. J Colloid Interface Sci 2011; 363:261-7. [PMID: 21820124 DOI: 10.1016/j.jcis.2011.06.066] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/24/2011] [Accepted: 06/25/2011] [Indexed: 11/16/2022]
Abstract
Ionic liquid based microemulsions were characterized by absorption solvatochromic shifts, (1)H NMR and kinetic measurements in order to investigate the properties of the ionic liquid within the restricted geometry provided by microemulsions and the interactions of the ionic liquid with the interface. Experimental results show a significant difference between the interfaces of normal water and the new ionic liquid microemulsions. Absorption solvatochromic shift experiments and kinetic studies on the aminolysis of 4-nitrophenyl laurate by n-decylamine show that the polarity at the interface of the ionic liquid in oil microemulsions (IL/O) is higher than at the interface of water in oil microemulsions (W/O) despite the fact that the polarity of [bmim][BF(4)(-)] is lower than the polarity of water. (1)H NMR experiments showed that an increase in the ionic liquid content of the microemulsion led to an increase in the interaction between [bmim][BF(4)(-)] and TX-100. The reason for the higher polarity of the microemulsions with the ionic liquid can be explained in terms of the incorporation of higher levels of the ionic liquid at the interface of the microemulsions, as compared to water in the traditional systems.
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Affiliation(s)
- María Andújar-Matalobos
- Departamento de Química Física y Centro Singular de Investigación en Química Biológica y Materiales Moleculares, Universidad de Santiago, 15782 Santiago, Spain
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Astray G, Cid A, Manso JA, Mejuto JC, Moldes OA, Morales J. Alkaline Fading of Triarylmethyl Carbocations in Self-Assembly Microheterogeneous Media. Progress in Reaction Kinetics and Mechanism 2011. [DOI: 10.3184/146867811x12984793755693] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This review reports on the alkaline fading of crystal violet and other related carbocations in the presence of different microheterogeneous media (micelles, microemulsions and vesicles).
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Affiliation(s)
- G. Astray
- Physical Chemistry Department, Faculty of Science, University of Vigo at Ourense,32004-Ourense, Spain
| | - A. Cid
- Physical Chemistry Department, Faculty of Science, University of Vigo at Ourense,32004-Ourense, Spain
| | - J. A. Manso
- Physical Chemistry Department, Faculty of Science, University of Vigo at Ourense,32004-Ourense, Spain
| | - J. C. Mejuto
- Physical Chemistry Department, Faculty of Science, University of Vigo at Ourense,32004-Ourense, Spain
| | - O. A. Moldes
- Physical Chemistry Department, Faculty of Science, University of Vigo at Ourense,32004-Ourense, Spain
| | - J. Morales
- Physical Chemistry Department, Faculty of Science, University of Vigo at Ourense,32004-Ourense, Spain
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Crans DC, Baruah B, Ross A, Levinger NE. Impact of confinement and interfaces on coordination chemistry: Using oxovanadate reactions and proton transfer reactions as probes in reverse micelles. Coord Chem Rev 2009. [DOI: 10.1016/j.ccr.2009.01.031] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Astray G, Cid A, García-Río L, Hervella P, Mejuto J, Pérez-Lorenzo M. Organic Reactivity in Aot-Stabilized Microemulsions. Progress in Reaction Kinetics and Mechanism 2008. [DOI: 10.3184/146867807x273173] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Microemulsions are highly versatile reaction media, which currently find many applications. In this review, we shall describe recent trends in the use of microemulsions as organic reaction media, and present models for their functioning, in particular the pseudophase model. This model allows a quantitative explanation of organic reactivity in these microheterogeneous media.
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Affiliation(s)
- G. Astray
- Department of Physical Chemistry, Faculty of Sciences, University of Vigo, 32004-Ourense, Spain
| | - A. Cid
- Department of Physical Chemistry, Faculty of Sciences, University of Vigo, 32004-Ourense, Spain
| | - L. García-Río
- Department of Physical Chemistry, Faculty of Chemistry, University of Santiago de Compostela, 15706-Santiago de Compostela, Spain
| | - P. Hervella
- Department of Physical Chemistry, Faculty of Chemistry, University of Santiago de Compostela, 15706-Santiago de Compostela, Spain
| | - J.C. Mejuto
- Department of Physical Chemistry, Faculty of Sciences, University of Vigo, 32004-Ourense, Spain
| | - M. Pérez-Lorenzo
- Department of Physical Chemistry, Faculty of Sciences, University of Vigo, 32004-Ourense, Spain
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Cid-Samamed A, García-Río L, Fernández-Gándara D, Mejuto J, Morales J, Pérez-Lorenzo M. Influence of n-alkyl acids on the percolative phenomena in AOT-based microemulsions. J Colloid Interface Sci 2008; 318:525-9. [DOI: 10.1016/j.jcis.2007.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2007] [Revised: 10/30/2007] [Accepted: 11/02/2007] [Indexed: 11/29/2022]
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Arias-Estevez M, Astray G, Cid A, Fernández-Gándara D, García-Río L, Mejuto JC. Influence of colloid suspensions of humic acids upon the alkaline fading of carbocations. J PHYS ORG CHEM 2008. [DOI: 10.1002/poc.1317] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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García-Río L, Mejuto JC, Pérez-Lorenzo M. Simultaneous effect of microemulsions and phase-transfer agents on aminolysis reactions. J Phys Chem B 2007; 111:11149-56. [PMID: 17760440 DOI: 10.1021/jp0743323] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The catalytic effect of triethylene glycol dimethyl ether (glyme) on the butylaminolysis of 4-nitrophenylcaprate (NPC) in water/AOT/chlorobenzene microemulsions has been studied. Experimental results show the existence of four simultaneous reaction pathways. One of them takes place at the microemulsion interphase where the rate-determining step of butylaminolysis is the formation of the addition intermediate, T+/-. The locus of the other three pathways is the continuous medium of the microemulsion. These three pathways consist of the decomposition of the addition intermediate catalyzed by butylamine, by glyme, and by both of them. The kinetic model allows us to obtain the value of every rate and distribution constant involved in the overall reaction mechanism. We must emphasize that the reactions located in the continuous medium exhibit a kinetic behavior similar to the corresponding one found in pure chlorobenzene. On the basis of the pseudophase model, the percentage of reaction in each of the microdomains of the microemulsion has been calculated. Likewise, changes in the loci of reaction from the interphase to the continuous medium as a function of catalyst concentration have been proved.
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Affiliation(s)
- L García-Río
- Departamento de Química Física, Facultade de Química, Universidade de Santiago, 15782 Santiago, Spain.
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Samant BS, Saraf YP, Bhagwat SS. Chlorination of aromatic compounds in micellar media: regioselectivity. J Colloid Interface Sci 2006; 302:207-13. [PMID: 16806254 DOI: 10.1016/j.jcis.2006.06.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2006] [Revised: 06/05/2006] [Accepted: 06/08/2006] [Indexed: 11/19/2022]
Abstract
Chlorination of phenol and ortho-chlorophenol was studied in micellar media in order to observe the effect on regioselectivity. Hydrogen peroxide/hydrochloric acid-aqueous system, which is environmentally a safer route was employed for chlorination. Selectivity ratio was found to be dependent on the nature and concentration of the surfactant. Ortho/para selectivity ratio up to 12 was realized for the chlorination of phenol. 2,6-/2,4-dichlorophenol ratio up to 1.01 was realized for the chlorination of ortho-chlorophenol.
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Affiliation(s)
- B S Samant
- Chemical Engineering Division, Institute of Chemical Technology, University of Mumbai, Matunga, Mumbai 400019, India
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