The Experts below are selected from a list of 107721 Experts worldwide ranked by ideXlab platform
Joseph A Gauthier - One of the best experts on this subject based on the ideXlab platform.
-
unified approach to implicit and explicit solvent simulations of Electrochemical Reaction energetics
Journal of Chemical Theory and Computation, 2019Co-Authors: Joseph A Gauthier, Stefan Ringe, Colin F Dickens, Hendrik H Heenen, Sudarshan Vijay, Karen ChanAbstract:One of the major open challenges in ab initio simulations of the Electrochemical interface is the determination of Electrochemical barriers under a constant driving force. Existing methods to do so include extrapolation techniques based on fully explicit treatments of the electrolyte, as well as implicit solvent models which allow for a continuous variation in electrolyte charge. Emerging hybrid continuum models have the potential to revolutionize the field, since they account for the electrolyte with little computational cost while retaining some explicit electrolyte, representing a "best of both worlds" method. In this work, we present a unified approach to determine Reaction energetics from fully explicit, implicit, and hybrid treatments of the electrolyte based on a new multicapacitor model of the Electrochemical interface. A given electrode potential can be achieved by a variety of interfacial structures; a crucial insight from this work is that the effective surface charge gives a good proxy of the local potential, the true driving force of Electrochemical processes. In contrast, we show that the traditionally considered work function gives rise to multivalued functions depending on the simulation cell size. Furthermore, we show that the Reaction energetics are largely insensitive to the countercharge distribution chosen in hybrid implicit/explicit models, which means that any of the myriad implicit electrolyte models can be equivalently applied. This work thus paves the way for the accurate treatment of ab initio Reaction energetics of general surface Electrochemical processes using both implicit and explicit electrolytes.
-
challenges in modeling Electrochemical Reaction energetics with polarizable continuum models
ACS Catalysis, 2019Co-Authors: Joseph A Gauthier, Stefan Ringe, Colin F Dickens, Alejandro J Garza, Alexis T Bell, Martin HeadgordonAbstract:A major challenge in the modeling of Electrochemical phenomena is the accurate description of the interface between an electrolyte and a charged conductor. Polarizable continuum models (PCM) have b...
J Olivierfourcade - One of the best experts on this subject based on the ideXlab platform.
-
changes in oxidation state and magnetic order of iron atoms during the Electrochemical Reaction of lithium with nife2o4
Electrochemistry Communications, 2003Co-Authors: Ricardo Alcantara, M Jaraba, P Lavela, J L Tirado, J C Jumas, J OlivierfourcadeAbstract:The mixed transition-metal spinel oxide NiFe2O4 is used for the first time as active electrode materials vs. lithium metal in test cells. Reversible capacities close to 900 mAh/g are found. Due to the poorly crystalline nature of the products of Electrochemical Reaction, diffraction procedures give little information about the iron forms in the Reaction products. The use of Mossbauer spectroscopy allows to monitor the mechanism of the Electrochemical Reaction with lithium of the spinel. During the first discharge, the amorphization process is accompanied by metal reduction. The reversible redox Reaction FeIII↔Fe0 accounts for the cycling capacity. However, magnetic ordering is lost during the first discharge and is not recovered in subsequent cycling or in the iron metal products.
-
changes in oxidation state and magnetic order of iron atoms during the Electrochemical Reaction of lithium with nife2o4
Electrochemistry Communications, 2003Co-Authors: Ricardo Alcantara, M Jaraba, P Lavela, J L Tirado, J C Jumas, J OlivierfourcadeAbstract:Abstract The mixed transition-metal spinel oxide NiFe2O4 is used for the first time as active electrode materials vs. lithium metal in test cells. Reversible capacities close to 900 mAh/g are found. Due to the poorly crystalline nature of the products of Electrochemical Reaction, diffraction procedures give little information about the iron forms in the Reaction products. The use of 57 Fe Mossbauer spectroscopy allows to monitor the mechanism of the Electrochemical Reaction with lithium of the spinel. During the first discharge, the amorphization process is accompanied by metal reduction. The reversible redox Reaction FeIII↔Fe0 accounts for the cycling capacity. However, magnetic ordering is lost during the first discharge and is not recovered in subsequent cycling or in the iron metal products.
Andras Kis - One of the best experts on this subject based on the ideXlab platform.
-
Electrochemical Reaction in single layer mos2 nanopores opened atom by atom
Nano Letters, 2015Co-Authors: Jiandong Feng, Ke Liu, Dumitru Dumcenco, M J Graf, Martina Lihter, Roman D Bulushev, Duncan T L Alexander, Daria Krasnozhon, T Vuletic, Andras KisAbstract:Ultrathin nanopore membranes based on 2D materials have demonstrated ultimate resolution toward DNA sequencing. Among them, molybdenum disulfide (MoS2) shows long-term stability as well as superior sensitivity enabling high throughput performance. The traditional method of fabricating nanopores with nanometer precision is based on the use of focused electron beams in transmission electron microscope (TEM). This nanopore fabrication process is time-consuming, expensive, not scalable, and hard to control below 1 nm. Here, we exploited the Electrochemical activity of MoS2 and developed a convenient and scalable method to controllably make nanopores in single-layer MoS2 with subnanometer precision using Electrochemical Reaction (ECR). The Electrochemical Reaction on the surface of single-layer MoS2 is initiated at the location of defects or single atom vacancy, followed by the successive removals of individual atoms or unit cells from single-layer MoS2 lattice and finally formation of a nanopore. Step-like fe...
-
Electrochemical Reaction in single layer mos2 nanopores opened atom by atom
arXiv: Soft Condensed Matter, 2015Co-Authors: Jiandong Feng, Ke Liu, Dumitru Dumcenco, M J Graf, Martina Lihter, Roman D Bulushev, Duncan T L Alexander, Daria Krasnozhon, T Vuletic, Andras KisAbstract:Ultrathin nanopore membranes based on 2D materials have demonstrated ultimate resolution toward DNA sequencing. Among them, molybdenum disulphide (MoS2) shows long-term stability as well as superior sensitivity enabling high throughput performance. The traditional method of fabricating nanopores with nanometer precision is based on the use of focused electron beams in transmission electron microscope (TEM). This nanopore fabrication process is time-consuming, expensive, not scalable and hard to control below 1 nm. Here, we exploited the Electrochemical activity of MoS2 and developed a convenient and scalable method to controllably make nanopores in single-layer MoS2 with sub-nanometer precision using Electrochemical Reaction (ECR). The Electrochemical Reaction on the surface of single-layer MoS2 is initiated at the location of defects or single atom vacancy, followed by the successive removals of individual atoms or unit cells from single-layer MoS2 lattice and finally formation of a nanopore. Step-like features in the ionic current through the growing nanopore provide direct feedback on the nanopore size inferred from a widely used conductance vs. pore size model. Furthermore, DNA translocations can be detected in-situ when as-fabricated MoS2 nanopores are used. The atomic resolution and accessibility of this approach paves the way for mass production of nanopores in 2D membranes for potential solid-state nanopore sequencing.
Ricardo Alcantara - One of the best experts on this subject based on the ideXlab platform.
-
electron paramagnetic resonance x ray diffraction mossbauer spectroscopy and Electrochemical studies on nanocrystalline fesn2 obtained by reduction of salts in tetraethylene glycol
Chemistry of Materials, 2010Co-Authors: Uche G Nwokeke, Ricardo Alcantara, J L Tirado, R Stoyanova, M Yoncheva, E ZhechevaAbstract:Nanocrystalline FeSn2 was prepared by chemical reduction of Sn−Fe chlorides in tetraethylene glycol using a “one-pot” method. Structural characterization is carried out by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and 119Sn Mossbauer spectroscopy. The Electrochemical Reaction of nanocrystalline FeSn2 with Li was examined by electron paramagnetic resonance (EPR) and 57Fe Mossbauer spectroscopy. Nanocrystalline FeSn2 delivers reversible capacities of about 600 mAhg−1 vs lithium after 20 cycles. The mechanism of the Electrochemical Reaction involves the conversion of FeSn2 into LixSn phases and superparamagnetic iron (or tin-doped iron) nanoparticles. The composition and the dimensions of the superparamagnetic particles depend on the depth of discharge. The Electrochemically formed superparamagnetic particles are preserved in the course of the reverse Electrochemical Reaction.
-
changes in oxidation state and magnetic order of iron atoms during the Electrochemical Reaction of lithium with nife2o4
Electrochemistry Communications, 2003Co-Authors: Ricardo Alcantara, M Jaraba, P Lavela, J L Tirado, J C Jumas, J OlivierfourcadeAbstract:The mixed transition-metal spinel oxide NiFe2O4 is used for the first time as active electrode materials vs. lithium metal in test cells. Reversible capacities close to 900 mAh/g are found. Due to the poorly crystalline nature of the products of Electrochemical Reaction, diffraction procedures give little information about the iron forms in the Reaction products. The use of Mossbauer spectroscopy allows to monitor the mechanism of the Electrochemical Reaction with lithium of the spinel. During the first discharge, the amorphization process is accompanied by metal reduction. The reversible redox Reaction FeIII↔Fe0 accounts for the cycling capacity. However, magnetic ordering is lost during the first discharge and is not recovered in subsequent cycling or in the iron metal products.
-
changes in oxidation state and magnetic order of iron atoms during the Electrochemical Reaction of lithium with nife2o4
Electrochemistry Communications, 2003Co-Authors: Ricardo Alcantara, M Jaraba, P Lavela, J L Tirado, J C Jumas, J OlivierfourcadeAbstract:Abstract The mixed transition-metal spinel oxide NiFe2O4 is used for the first time as active electrode materials vs. lithium metal in test cells. Reversible capacities close to 900 mAh/g are found. Due to the poorly crystalline nature of the products of Electrochemical Reaction, diffraction procedures give little information about the iron forms in the Reaction products. The use of 57 Fe Mossbauer spectroscopy allows to monitor the mechanism of the Electrochemical Reaction with lithium of the spinel. During the first discharge, the amorphization process is accompanied by metal reduction. The reversible redox Reaction FeIII↔Fe0 accounts for the cycling capacity. However, magnetic ordering is lost during the first discharge and is not recovered in subsequent cycling or in the iron metal products.
Stefan Ringe - One of the best experts on this subject based on the ideXlab platform.
-
unified approach to implicit and explicit solvent simulations of Electrochemical Reaction energetics
Journal of Chemical Theory and Computation, 2019Co-Authors: Joseph A Gauthier, Stefan Ringe, Colin F Dickens, Hendrik H Heenen, Sudarshan Vijay, Karen ChanAbstract:One of the major open challenges in ab initio simulations of the Electrochemical interface is the determination of Electrochemical barriers under a constant driving force. Existing methods to do so include extrapolation techniques based on fully explicit treatments of the electrolyte, as well as implicit solvent models which allow for a continuous variation in electrolyte charge. Emerging hybrid continuum models have the potential to revolutionize the field, since they account for the electrolyte with little computational cost while retaining some explicit electrolyte, representing a "best of both worlds" method. In this work, we present a unified approach to determine Reaction energetics from fully explicit, implicit, and hybrid treatments of the electrolyte based on a new multicapacitor model of the Electrochemical interface. A given electrode potential can be achieved by a variety of interfacial structures; a crucial insight from this work is that the effective surface charge gives a good proxy of the local potential, the true driving force of Electrochemical processes. In contrast, we show that the traditionally considered work function gives rise to multivalued functions depending on the simulation cell size. Furthermore, we show that the Reaction energetics are largely insensitive to the countercharge distribution chosen in hybrid implicit/explicit models, which means that any of the myriad implicit electrolyte models can be equivalently applied. This work thus paves the way for the accurate treatment of ab initio Reaction energetics of general surface Electrochemical processes using both implicit and explicit electrolytes.
-
challenges in modeling Electrochemical Reaction energetics with polarizable continuum models
ACS Catalysis, 2019Co-Authors: Joseph A Gauthier, Stefan Ringe, Colin F Dickens, Alejandro J Garza, Alexis T Bell, Martin HeadgordonAbstract:A major challenge in the modeling of Electrochemical phenomena is the accurate description of the interface between an electrolyte and a charged conductor. Polarizable continuum models (PCM) have b...