The role of hydrophobic hydration in the free energy of chemical reactions at the gold/water interface: Size and position effects

2021 ◽  
Vol 155 (20) ◽  
pp. 204706
Author(s):  
Alessandra Serva ◽  
Martina Havenith ◽  
Simone Pezzotti
Keyword(s):  
Free Energy ◽  
Chemical Reactions ◽  
Hydrophobic Hydration ◽  
Water Interface ◽  
Position Effects

scholarly journals Size dependence of hydrophobic hydration at electrified gold/water interfaces

2021 ◽  
Vol 118 (15) ◽  
pp. e2023867118
Author(s):  
Alessandra Serva ◽  
Mathieu Salanne ◽  
Martina Havenith ◽  
Simone Pezzotti
Keyword(s):  
Free Energy ◽  
Energy Cost ◽  
Correction Term ◽  
Hydrophobic Hydration ◽  
Outer Sphere ◽  
Gold Surface ◽  
Electrochemical Reactions ◽  
Water Interface ◽  
Hydrophobic Solutes ◽  
Small Hydrophobic

Hydrophobic hydration at metal/water interfaces actively contributes to the energetics of electrochemical reactions, e.g. CO2 and N2 reduction, where small hydrophobic molecules are involved. In this work, constant applied potential molecular dynamics is employed to study hydrophobic hydration at a gold/water interface. We propose an adaptation of the Lum–Chandler–Weeks (LCW) theory to describe the free energy of hydrophobic hydration at the interface as a function of solute size and applied voltage. Based on this model we are able to predict the free energy cost of cavity formation at the interface directly from the free energy cost in the bulk plus an interface-dependent correction term. The interfacial water network contributes significantly to the free energy, yielding a preference for outer-sphere adsorption at the gold surface for ideal hydrophobes. We predict an accumulation of small hydrophobic solutes of sizes comparable to CO or N2, while the free energy cost to hydrate larger hydrophobes, above 2.5-Å radius, is shown to be greater at the interface than in the bulk. Interestingly, the transition from the volume dominated to the surface dominated regimes predicted by the LCW theory in the bulk is also found to take place for hydrophobes at the Au/water interface but occurs at smaller cavity radii. By applying the adapted LCW theory to a simple model addition reaction, we illustrate some implications of our findings for electrochemical reactions.

Evaluation of Asphaltene Adsorption Free Energy at the Oil–Water Interface: Role of Heteroatoms

2020 ◽  
Vol 34 (5) ◽  
pp. 5267-5280 ◽  
Author(s):  
Jo Mizuhara ◽  
Yunfeng Liang ◽  
Yoshihiro Masuda ◽  
Kazuya Kobayashi ◽  
Hiroki Iwama ◽  
...  
Keyword(s):  
Free Energy ◽  
Water Interface ◽  
Adsorption Free Energy ◽  
Oil Water

scholarly journals Modeling C. elegans as a thermodynamic stable system

2015 ◽  
Author(s):  
Joshua Elkington
Keyword(s):  
Free Energy ◽  
Survival Rate ◽  
Chemical Reactions ◽  
Small Rna ◽  
Redox Reactions ◽  
C Elegans ◽  
Short Lifespan ◽  
Different Types ◽  
Rna Pathways

The nematode, C. elegans is a useful organism to study aging due to its relatively short lifespan and genetic tractability. The lifespan of a population of worms can be easily determined. Under normal conditions worms can live up to 2 weeks, and if they are under heat shock, most worms die within 2 days. In order to investigate the effects of drug concentration and temperature on an organism ability to survive, a model based on Gibbs Free Energy was used to determine under what conditions is survival rate increased or decreased. Furthermore, along with wildtype, N2, worms, a small RNA mutant, eri-6 (mg379), was studied to try to understand the role of small RNA pathways in aging and stress response. The ultimate goal of the model is to prove that the types of chemical reactions within an organism depend on temperature and substrate concentration. Worm lifespan was used as a marker for chemical reactions within an organism. Differences in aging may be a result of different types of chemistry occurring in an organism. For example a long-lived species may used redox reactions more than a short-lived species.

scholarly journals Modeling C. elegans as a thermodynamic stable system

2015 ◽  
Author(s):  
Joshua Elkington
Keyword(s):  
Free Energy ◽  
Survival Rate ◽  
Chemical Reactions ◽  
Small Rna ◽  
Redox Reactions ◽  
C Elegans ◽  
Short Lifespan ◽  
Different Types ◽  
Rna Pathways

The nematode, C. elegans is a useful organism to study aging due to its relatively short lifespan and genetic tractability. The lifespan of a population of worms can be easily determined. Under normal conditions worms can live up to 2 weeks, and if they are under heat shock, most worms die within 2 days. In order to investigate the effects of drug concentration and temperature on an organism ability to survive, a model based on Gibbs Free Energy was used to determine under what conditions is survival rate increased or decreased. Furthermore, along with wildtype, N2, worms, a small RNA mutant, eri-6 (mg379), was studied to try to understand the role of small RNA pathways in aging and stress response. The ultimate goal of the model is to prove that the types of chemical reactions within an organism depend on temperature and substrate concentration. Worm lifespan was used as a marker for chemical reactions within an organism. Differences in aging may be a result of different types of chemistry occurring in an organism. For example a long-lived species may used redox reactions more than a short-lived species.

Fine structure and properties of defects in naturally occurring silicates and oxides

1990 ◽  
Vol 48 (4) ◽  
pp. 460-461
Author(s):  
David R. Veblen
Keyword(s):  
Chemical Reactions ◽  
High Resolution Electron Microscopy ◽  
Extended Defects ◽  
Single Chain ◽  
Naturally Occurring ◽  
Resolution Electron ◽  
Fine Structures ◽  
Image Simulations ◽  
Similar Crystal Structure

Extended defects and interfaces control many processes in rock-forming minerals, from chemical reactions to rock deformation. In many cases, it is not the average structure of a defect or interface that is most important, but rather the structure of defect terminations or offsets in an interface. One of the major thrusts of high-resolution electron microscopy in the earth sciences has been to identify the role of defect fine structures in reactions and to determine the structures of such features. This paper will review studies using HREM and image simulations to determine the structures of defects in silicate and oxide minerals and present several examples of the role of defects in mineral chemical reactions. In some cases, the geological occurrence can be used to constrain the diffusional properties of defects.The simplest reactions in minerals involve exsolution (precipitation) of one mineral from another with a similar crystal structure, and pyroxenes (single-chain silicates) provide a good example. Although conventional TEM studies have led to a basic understanding of this sort of phase separation in pyroxenes via spinodal decomposition or nucleation and growth, HREM has provided a much more detailed appreciation of the processes involved.

The role of (bio)surfactant sorption in promoting the bioavailability of nutrients localized at the solid-water interface

1999 ◽  
Vol 39 (7) ◽  
pp. 91-98 ◽  
Author(s):  
Ryan N. Jordan ◽  
Eric P. Nichols ◽  
Alfred B. Cunningham
Keyword(s):  
Mass Transfer ◽  
Cell Membrane ◽  
Substrate Concentration ◽  
Water Interface ◽  
Industrial Systems ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Surfactant Sorption

Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.

Comments on the Antonow and interfacial interaction rules

1990 ◽  
Vol 55 (5) ◽  
pp. 1143-1148 ◽  
Author(s):  
Jan Kloubek
Keyword(s):  
Free Energy ◽  
Energy Minimization ◽  
Interfacial Interaction ◽  
Aliphatic Hydrocarbon ◽  
Theoretical Base ◽  
Water Interface ◽  
Free Energy Minimization ◽  
Interaction Rule

Results presented for the aliphatic hydrocarbon-water interface show that the recent hypothesis of the free energy minimization called interfacial interaction rule, which was suggested as a theoretical base of the Antonow rule, cannot be generally valid.

Critical role of nanocomposites at air–water interface: From aqueous foams to foam-based lightweight functional materials

2021 ◽  
Vol 416 ◽  
pp. 129121
Author(s):  
Kai Yu ◽  
Bin Li ◽  
Huagui Zhang ◽  
Zhentao Wang ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Critical Role ◽  
Functional Materials ◽  
Water Interface ◽  
Aqueous Foams ◽  
Air Water Interface

Topography of the Free Energy Landscape on the Claisen-Schmidt Condensation: Solvent and Temperature Effect in the Rate-Controlling Step

2021 ◽  
Author(s):  
Nayara Dantas Coutinho ◽  
Hugo Gontijo Machado ◽  
Valter Henrique Carvalho-Silva ◽  
Wender A. Silva
Keyword(s):  
Free Energy ◽  
Temperature Effect ◽  
Strong Influence ◽  
Aldol Condensation ◽  
Energy Landscape ◽  
Bond Formation ◽  
Free Energy Landscape ◽  
Rate Controlling Step ◽  
Formation Step

Recent studies have assigned hydroxide elimination and C=C bond formation step in base-promoted aldol condensation the role of having a strong influence in the overall rate reaction, in contrast to...

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