Physchem

Research

9 pages, 3075 KiB

Open AccessArticle

Acid-Catalyzed Esterification of Betaines: Theoretical Exploration of the Impact of the Carbon Chain Length on the Reaction Mechanism

by Richail Dubien Moulandou-Koumba, Frédéric Guégan, Jean-Maurille Ouamba, Samuel N’Sikabaka and Gilles Frapper

Physchem 2021, 1(3), 288-296; https://doi.org/10.3390/physchem1030022 - 7 Dec 2021

Viewed by 3046

Abstract

Betaine derivatives, especially esters, are compounds of interest for the development of a more sustainable fine chemistry, as they are widely available from biomass and currently produced as side-products from various industries (among which, sugar production). In this publication, we studied the impact [...] Read more.

Betaine derivatives, especially esters, are compounds of interest for the development of a more sustainable fine chemistry, as they are widely available from biomass and currently produced as side-products from various industries (among which, sugar production). In this publication, we studied the impact of carbon chain length on three considered reaction mechanisms for the esterification of (CH₃)₃N(CH₂)_nCO₂ betaine (n = 1, 2, 3) with glycerol under acid catalysis. DFT calculations show that the mechanism proposed by Bachmann–Frapper et al. may also be active here, but it can interestingly be seen as an avatar of the former proposition by Watson. Conversely, Ingold’s proposition is in this case too energetically prevented. Overall, lower activation barriers and higher reaction exergonicity are reported, suggesting esterification of longer carbon-chain based betaines is more readily achieved. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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9 pages, 2166 KiB

Open AccessArticle

The Local Structure of the BiS₂ Layer in RE(O,F)BiS₂ Determined by In-Plane Polarized X-ray Absorption Measurements

by G. M. Pugliese, L. Tortora, E. Paris, T. Wakita, K. Terashima, A. Puri, M. Nagao, R. Higashinaka, T. D. Matsuda, Y. Aoki, T. Yokoya, T. Mizokawa and N. L. Saini

Physchem 2021, 1(3), 250-258; https://doi.org/10.3390/physchem1030019 - 10 Nov 2021

Cited by 1 | Viewed by 3054

Abstract

We have investigated the local structure of BiS

_{2}

-based layered materials by Bi L

_{3}

-edge extended X-ray absorption fine structure (EXAFS) measurements performed on single crystal samples with polarization of the X-ray beam parallel to the BiS

_{2}

plane. The results [...] Read more.

We have investigated the local structure of BiS

_{2}

-based layered materials by Bi L

_{3}

-edge extended X-ray absorption fine structure (EXAFS) measurements performed on single crystal samples with polarization of the X-ray beam parallel to the BiS

_{2}

plane. The results confirm highly instable nature of BiS

_{2}

layer, characterized by ferroelectric like distortions. The distortion amplitude, determined by the separation between the two in-plane (Bi-S1) bonds, is found to be highest in LaO

_{0.77}

F

_{0.23}

BiS

_{2}

with

Δ

R∼0.26 Å and lowest in NdO

_{0.71}

F

_{0.29}

BiS

_{2}

with

Δ

R∼0.13 Å. Among the systems with intrinsic doping, CeOBiS

_{2}

shows smaller distortion (

Δ

R∼0.15 Å) than PrOBiS

_{2}

(

Δ

R∼0.18 Å) while the highest distortion appears for EuFBiS

_{2}

revealing

Δ

R∼0.22 Å. It appears that the distortion amplitude is controlled by the nature of the RE(O,F) spacer layer in the RE(O,F)BiS

_{2}

structure. The X-ray absorption near edge structure (XANES) spectra, probing the local geometry, shows a spectral weight transfer that evolves systematically with the distortion amplitude in the BiS

_{2}

-layer. The results provide a quantitative measurements of the local distortions in the instable BiS

_{2}

-layer with direct implication on the physical properties of these materials. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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11 pages, 3349 KiB

Open AccessArticle

A Computational Study of Molecular Mechanism of Chloroquine Resistance by Chloroquine Resistance Transporter Protein of Plasmodium falciparum via Molecular Modeling and Molecular Simulations

by Chandan Patel and Dipankar Roy

Physchem 2021, 1(3), 232-242; https://doi.org/10.3390/physchem1030017 - 14 Oct 2021

Cited by 4 | Viewed by 3427

Abstract

The molecular mechanism of chloroquine resistance by the chloroquine resistance transporter protein of Plasmodium sp. is explored using molecular modeling and computational methods. The key mutation, lysine(K)-76 to threonine(T) (LYS76THR) in the transporter protein pertains to increased recognition of the protonated forms of [...] Read more.

The molecular mechanism of chloroquine resistance by the chloroquine resistance transporter protein of Plasmodium sp. is explored using molecular modeling and computational methods. The key mutation, lysine(K)-76 to threonine(T) (LYS76THR) in the transporter protein pertains to increased recognition of the protonated forms of the antimalarial drug. Such enhanced affinity can promote drug efflux from host digestive vacuole, rendering aminoquinoline-based treatment ineffective. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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7 pages, 571 KiB

Open AccessArticle

Dislocations as a Tool for Nanostructuring Advanced Materials

by Vladyslav Turlo

Physchem 2021, 1(3), 225-231; https://doi.org/10.3390/physchem1030016 - 26 Sep 2021

Cited by 1 | Viewed by 2584

Abstract

Dislocations present unique opportunities for nanostructuring advanced structural and functional materials due to the recent discoveries of linear complexions thermodynamically stable nanoscale features with unique chemistry and structure confined at dislocations. The formation of such features is driven by solute segregation near the [...] Read more.

Dislocations present unique opportunities for nanostructuring advanced structural and functional materials due to the recent discoveries of linear complexions thermodynamically stable nanoscale features with unique chemistry and structure confined at dislocations. The formation of such features is driven by solute segregation near the dislocation core and results in the stabilization of dislocations, altering mechanical, thermodynamic, and transport properties of the final material. This perspective article gives an overview of the recent discoveries and predictions made by high-resolution experimental characterization techniques, as well as large-scale atomistic simulations in the newly emerging field of linear complexions. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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10 pages, 1421 KiB

Open AccessArticle

Predicting 1,9-Decadiene−Water Partition Coefficients Using the 3D-RISM-KH Molecular Solvation Theory

by Dipankar Roy, Devjyoti Dutta and Andriy Kovalenko

Physchem 2021, 1(2), 215-224; https://doi.org/10.3390/physchem1020015 - 4 Sep 2021

Viewed by 2934

Abstract

The Three-Dimensional Reference Interaction Site Model (3D-RISM) with Kovalenko−Hirata (KH) closure is applied to calculate the 1,9-Decadiene/Water partition coefficients for a diverse class of compounds. The liquid state of 1,9-Decadiene is represented with the united atom TraPPE force field parameters. The 3D-RISM-KH computed [...] Read more.

The Three-Dimensional Reference Interaction Site Model (3D-RISM) with Kovalenko−Hirata (KH) closure is applied to calculate the 1,9-Decadiene/Water partition coefficients for a diverse class of compounds. The liquid state of 1,9-Decadiene is represented with the united atom TraPPE force field parameters. The 3D-RISM-KH computed partition functions are in good agreement with the experimental results. Our computational scheme can be used for a quantitative structure partitioning prediction for decadiene-water system, which has been used in membrane-mimicking of the egg-lecithin/water permeability experiments. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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13 pages, 754 KiB

Open AccessArticle

The Water Polymorphism and the Liquid–Liquid Transition from Transport Data

by Francesco Mallamace, Domenico Mallamace, Giuseppe Mensitieri, Sow-Hsin Chen, Paola Lanzafame and Georgia Papanikolaou

Physchem 2021, 1(2), 202-214; https://doi.org/10.3390/physchem1020014 - 25 Aug 2021

Cited by 4 | Viewed by 3225

Abstract

NMR spectroscopic literature data are used, in a wide temperature-pressure range (180–350 K and 0.1–400 MPa), to study the water polymorphism and the validity of the liquid–liquid transition (LLT) hypothesis. We have considered the self-diffusion coefficient

D_{S}

and the reorientational correlation time [...] Read more.

NMR spectroscopic literature data are used, in a wide temperature-pressure range (180–350 K and 0.1–400 MPa), to study the water polymorphism and the validity of the liquid–liquid transition (LLT) hypothesis. We have considered the self-diffusion coefficient

D_{S}

and the reorientational correlation time

τ_{θ}

(obtained from spin-lattice

T_{1}

relaxation times), measured, respectively, in bulk and emulsion liquid water from the stable to well inside the metastable supercooled region. As an effect of the hydrogen bond (HB) networking, the isobars of both these transport functions evolve with T by changing by several orders of magnitude, whereas their pressure dependence become more and more pronounced at lower temperatures. Both these transport functions were then studied according to the Adam–Gibbs model, typical of glass forming liquids, obtaining the water configurational entropy and the corresponding specific heat contribution. The comparison of the evaluated

C_{P, c o n f}

isobars with the experimentally measured water specific heat reveals the full consistency of this analysis. In particular, the observed

C_{P, c o n f}

maxima and its diverging behaviors clearly reveals the presence of the LLT and with a reasonable approximation the liquid–liquid critical point (LLCP) locus in the phase diagram. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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13 pages, 1715 KiB

Open AccessArticle

Unusual Para-Substituent Effects on the Intramolecular Hydrogen Bond in Hydrazone-Based Switches: Insights from Chemical Landscape Analysis and DFT Calculations

by Vesselina Paskaleva, Stefan Dobrev, Nikolay Kochev, Silvia Angelova and Liudmil Antonov

Physchem 2021, 1(2), 189-201; https://doi.org/10.3390/physchem1020013 - 5 Aug 2021

Cited by 1 | Viewed by 2865

Abstract

Тhe adequacy of chemical property predictions strongly depends on the structure representation, including the proper treatment of the tautomeric and isomeric forms. A combination of an in-house developed open-source tool for automatic generation of tautomers, Ambit-Tautomer, based on H-atom shift rules and standard [...] Read more.

Тhe adequacy of chemical property predictions strongly depends on the structure representation, including the proper treatment of the tautomeric and isomeric forms. A combination of an in-house developed open-source tool for automatic generation of tautomers, Ambit-Tautomer, based on H-atom shift rules and standard quantum chemical (DFT) calculations is used for a detailed investigation of the possible geometric isomers, conformers and tautomers of unsubstituted and para-substituted phenylhydrazones, systems with experimentally observed unusual para-substituent effects on the intramolecular hydrogen bond (IMHB) for E-isomers of the compounds. The computational results show that the energetically preferred E-isomers are characterized by stronger IMHBs than the corresponding Z-isomers. The HN–N=C–C=N molecular fragment in the E-configurations is less sensitive to the substitution effect than the HN–N=C–C=O fragment in the isomers with Z-configuration. A probable reason for this decreased sensitivity of E-isomers to phenyl ring substitution is the more efficient conjugation and charge distribution in the HN–N=C–C=N fragment. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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13 pages, 1840 KiB

Open AccessArticle

Raman Sensor for the Determination of Gas Solubility

by Gregor Lipinski and Markus Richter

Physchem 2021, 1(2), 176-188; https://doi.org/10.3390/physchem1020012 - 4 Aug 2021

Viewed by 3469

Abstract

Efficient and environmentally responsible use of resources requires the development and optimization of gas separation processes. A promising approach is the use of liquids that are designed for specific tasks, e.g., the capture of carbon dioxide or other greenhouse gases. This requires an [...] Read more.

Efficient and environmentally responsible use of resources requires the development and optimization of gas separation processes. A promising approach is the use of liquids that are designed for specific tasks, e.g., the capture of carbon dioxide or other greenhouse gases. This requires an accurate determination of gas solubilities for a broad range of temperatures and pressures. However, state of the art measurement techniques are often very time consuming or exhibit other pitfalls that prevent their use as efficient screening tools. Here, we show that the application of Raman spectroscopy through a compact measuring system can simplify data acquisition for the determination of gas solubilities in liquids. To demonstrate that this approach is expedient, we determined gas solubilities of carbon dioxide in water for three isotherms T = (288.15, 293.15, 298.15) K over a pressure range from p = (0.5–5) MPa and in three imidazolium-based ionic liquids for one isotherm T = 298.15 K at pressures from p = (0.1–5) MPa. When compared to data in the literature, all results are within the reported uncertainties of the measurement techniques involved. The developed analysis method eliminates the need for a lengthy volume or mass calibration of the sample prior to the measurements and, therefore, allows for fast screening of samples, which can help to advance gas separation processes in scientific and industrial applications. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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13 pages, 6307 KiB

Open AccessArticle

Plasmon-Mediated Oxidation Reaction on Au/p-Cu₂O: The Origin of Hot Holes

by Philipp Hawe, Vitor R. R. Silveira, Robert Bericat Vadell, Erik Lewin and Jacinto Sá

Physchem 2021, 1(2), 163-175; https://doi.org/10.3390/physchem1020011 - 27 Jul 2021

Cited by 2 | Viewed by 3156

Abstract

More sustainable solutions are needed to produce chemicals and fuels, mainly to face rising demands and mitigate climate change. Light, as a reagent, has emerged as a route to activate small molecules, e.g., H₂O, CO₂, N₂, and [...] Read more.

More sustainable solutions are needed to produce chemicals and fuels, mainly to face rising demands and mitigate climate change. Light, as a reagent, has emerged as a route to activate small molecules, e.g., H₂O, CO₂, N₂, and make complex chemicals in a process called photocatalysis. Several photosystems have been proposed, with plasmonic technology emerging as one the most promising technologies due to its high optical absorption and hot-carrier formation. However, the lifetime of hot carriers is unsuitable for direct use; therefore, they are normally coupled with suitable charge-accepting materials, such as semiconductors. Herein, a system is reported consisting of Au supported in p-Cu₂O. The combination of p-Cu₂O intrinsic photoactivity with the plasmonic properties of Au extended the system’s optical absorption range, increasing photocatalytic efficiency. More importantly, the system enabled us to study the underlying processes responsible for hot-hole transfer to p-Cu₂O. Based on photocatalytic studies, it was concluded that most of the holes involved in aniline photo-oxidation come from hot-carrier injections, not from the PIRET process. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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19 pages, 5930 KiB

Open AccessArticle

Adhesion and Structural Changes of PEGylated Lipid Nanocarriers on Silica Surfaces

by Philipp Grad, Katarina Edwards and Víctor Agmo Hernández

Physchem 2021, 1(2), 133-151; https://doi.org/10.3390/physchem1020009 - 15 Jul 2021

Cited by 1 | Viewed by 3854

Abstract

PEGylated lipid nanoparticles have a continuously expanding range of applications, particularly within pharmaceutical areas. Hereby, it is shown with the help of the Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) and other surface sensitive techniques that, at room temperature, PEGylated liposomes and lipodisks [...] Read more.

PEGylated lipid nanoparticles have a continuously expanding range of applications, particularly within pharmaceutical areas. Hereby, it is shown with the help of the Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) and other surface sensitive techniques that, at room temperature, PEGylated liposomes and lipodisks adhere strongly to silica surfaces resulting in the displacement of the hydration layer of silica and the formation of immobilized nanoparticle films. Furthermore, it is shown that drastic changes in the structure of the immobilized films occur if the temperature is increased to >35 °C. Thus, intact immobilized PEGylated liposomes rupture and spread, even in the gel phase state; immobilized lipodisks undergo complete separation of their components (bilayer forming lipids and PEGylated lipids) resulting in a monolayer of adsorbed PEGylated lipids; and PEGylated supported lipid bilayers release part of the water trapped between the lipid membrane and the surface. It is hypothesized that these changes occur mainly due to the changes in the configuration of PEG chains and a drastic decrease of the affinity of the polymer for water. The observed phenomena can be applied, e.g., for the production of defect-free supported lipid bilayers in the gel or liquid ordered phase states. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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13 pages, 3066 KiB

Open AccessArticle

Methane Production from H₂ + CO₂ Reaction: An Open Molecular Science Case for Computational and Experimental Studies

by Stefano Falcinelli, Andrea Capriccioli, Marzio Rosi, Carles Martì, Marco Parriani and Antonio Laganà

Physchem 2021, 1(1), 82-94; https://doi.org/10.3390/physchem1010006 - 2 Jun 2021

Cited by 4 | Viewed by 7183

Abstract

The article illustrates the synergy between theoretical/computational advances and advanced experimental achievements to pursue green chemistry and circular economy technological implementations. The specific green chemistry focus concerns the production of carbon neutral fuels by converting waste carbon dioxide into methane. Both theoretical-computational and [...] Read more.

The article illustrates the synergy between theoretical/computational advances and advanced experimental achievements to pursue green chemistry and circular economy technological implementations. The specific green chemistry focus concerns the production of carbon neutral fuels by converting waste carbon dioxide into methane. Both theoretical-computational and technological means were adopted to design a functional option implementing a heterogeneous catalysis process (Paul Sabatier (PS) catalytic reduction) to convert carbon dioxide into methane, and to further drive its evolution towards the employment of an alternative homogeneous gas phase plasma assisted technology. The details of both the theoretical and the experimental components of the study are presented and discussed. Future potential developments, including industrial ones, are outlined that are also from innovative collaborative economic prosumer model perspectives. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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13 pages, 2959 KiB

Open AccessArticle

An Electrochemical Impedance Study of Alkaline Water Splitting Using Fe Doped NiO Nanosheets

by Zhen Qiu, Yue Ma, Gunnar A. Niklasson and Tomas Edvinsson

Physchem 2021, 1(1), 69-81; https://doi.org/10.3390/physchem1010005 - 31 May 2021

Cited by 9 | Viewed by 6072

Abstract

Mixed nickel-iron (Ni-Fe) compounds have recently emerged as promising non-precious electrocatalysts for alkaline water splitting. The understanding of the charge-transfer mechanism involved in the multi-step Faradic reaction, however, is still limited for the overall electrochemical process. In this paper, electrochemical impedance spectroscopy (EIS) [...] Read more.

Mixed nickel-iron (Ni-Fe) compounds have recently emerged as promising non-precious electrocatalysts for alkaline water splitting. The understanding of the charge-transfer mechanism involved in the multi-step Faradic reaction, however, is still limited for the overall electrochemical process. In this paper, electrochemical impedance spectroscopy (EIS) measurements of Fe incorporated Ni oxide nanosheets were used to study the reaction kinetics for both hydrogen (HER) and oxygen (OER) evolution reactions in alkaline media. Our results showed that Fe incorporation improves the catalytic property of NiO nanosheets because of the lower reaction resistance and faster intermediate transformations. Detailed EIS modeling enables a separation of the surface coverage relaxation from the charge transfer resistance, with an inductive behavior observed in the low-frequency range for HER, holding important information on the dominating reaction mechanism. For OER, the good agreement between the EIS experimental results and a model with an inductance loop indicated that similar inductive behavior would be determining the EIS response at very low frequencies. The physical significance of the elementary steps gives insight into the governing reaction mechanisms involved in the electron and hole charge transfer, as well as the inherent properties of catalysts and their surface coverage relaxation. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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24 pages, 2585 KiB

Open AccessArticle

Vibrational Analysis of Benziodoxoles and Benziodazolotetrazoles

by Seth Yannacone, Kapil Dev Sayala, Marek Freindorf, Nicolay V. Tsarevsky and Elfi Kraka

Physchem 2021, 1(1), 45-68; https://doi.org/10.3390/physchem1010004 - 14 May 2021

Cited by 6 | Viewed by 5216

Abstract

Tetrazoles are well known for their high positive enthalpy of formation which makes them attractive as propellants, explosives, and energetic materials. As a step towards a deeper understanding of the stability of benziodazolotetrazole (BIAT)-based materials compared to their benziodoxole (BIO) counterparts, we investigated [...] Read more.

Tetrazoles are well known for their high positive enthalpy of formation which makes them attractive as propellants, explosives, and energetic materials. As a step towards a deeper understanding of the stability of benziodazolotetrazole (BIAT)-based materials compared to their benziodoxole (BIO) counterparts, we investigated in this work electronic structure features and bonding properties of two monovalent iodine precursors: 2-iodobenzoic acid and 5-(2-iodophenyl)tetrazole and eight hypervalent iodine (III) compounds: I-hydroxybenzidoxolone, I-methoxybenziodoxolone, I-ethoxybenziodoxolone, I-iso-propoxybenziodoxolone and the corresponding I-hydroxyben ziodazolotetrazole, I-methoxybenziodazolotetrazole, I-ethoxybenziodazolotetrazole and I-iso- propoxybenziodazolotetrazole. As an efficient tool for the interpretation of the experimental IR spectra and for the quantitative assessment of the I−C, I−N, and I−O bond strengths in these compounds reflecting substituent effects, we used the local vibrational mode analysis, originally introduced by Konkoli and Cremer, complemented by electron density and natural bond orbital analyses. Based on the hypothesis that stronger bonds correlate with increased stability, we predict that, for both series, i.e., substituted benziodoxoles and benziodazolotetrazoles, the stability increases as follows: I-iso-propoxy < I-ethoxy < I-methoxy < I-hydroxy. In particular, the I−N bonds in the benziodazolotetrazoles could be identified as the so-called trigger bonds being responsible for the initiation of explosive decomposition in benziodazolotetrazoles. The new insight gained by this work will allow for the design of new benziodazolotetrazole materials with controlled performance or stability based on the modulation of the iodine bonds with its three ligands. The local mode analysis can serve as an effective tool to monitor the bond strengths, in particular to identify potential trigger bonds. We hope that this article will foster future collaboration between the experimental and computational community being engaged in vibrational spectroscopy. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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Review

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15 pages, 5195 KiB

Open AccessReview

An Overview of Common Infrared Techniques for Detecting CO Intermediates on Metal Surfaces for Hydrocarbon Products

by Ahmed M. El-Zohry

Physchem 2022, 2(1), 1-15; https://doi.org/10.3390/physchem2010001 - 8 Jan 2022

Cited by 2 | Viewed by 2864

Abstract

Detection of intermediates during the catalytic process by infrared techniques has been widely implemented for many important reactions. For the reduction of CO₂ into hydrocarbons on metal surfaces, CO molecule is one of the most important transient species to be followed due [...] Read more.

Detection of intermediates during the catalytic process by infrared techniques has been widely implemented for many important reactions. For the reduction of CO₂ into hydrocarbons on metal surfaces, CO molecule is one of the most important transient species to be followed due to its involvement in several products’ pathways, and its distinct vibrational features. Herein, basic understandings behind these utilized infrared techniques are illustrated aiming for highlighting the potential of each infrared technique and its advantages over the other ones for detecting CO molecules on metal surfaces. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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12 pages, 1465 KiB

Open AccessReview

Molecular Terms of Dioxygen and Nitric Oxide

by Igor V. Khudyakov and Boris F. Minaev

Physchem 2021, 1(2), 121-132; https://doi.org/10.3390/physchem1020008 - 1 Jul 2021

Cited by 3 | Viewed by 4108

Abstract

Molecular terms of dioxygen and nitic oxide are presented. Electron spin resonance spectra of diatomic molecules corresponding to these terms are discussed. Gas-phase ESR can be a convenient method of monitoring paramagnetic pollutants in the atmosphere. We ran additional calculations in molecular physics [...] Read more.

Molecular terms of dioxygen and nitic oxide are presented. Electron spin resonance spectra of diatomic molecules corresponding to these terms are discussed. Gas-phase ESR can be a convenient method of monitoring paramagnetic pollutants in the atmosphere. We ran additional calculations in molecular physics for terms of these molecules and Zeeman transitions. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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26 pages, 6274 KiB

Open AccessReview

Net Zero and Catalysis: How Neutrons Can Help

by Stewart F. Parker and David Lennon

Physchem 2021, 1(1), 95-120; https://doi.org/10.3390/physchem1010007 - 9 Jun 2021

Cited by 9 | Viewed by 5485

Abstract

Net Zero has the aim of achieving equality between the amount of greenhouse gas emissions produced and the amount removed from the atmosphere. There is widespread acceptance that for Net Zero to be achievable, chemistry, and hence catalysis, must play a major role. [...] Read more.

Net Zero has the aim of achieving equality between the amount of greenhouse gas emissions produced and the amount removed from the atmosphere. There is widespread acceptance that for Net Zero to be achievable, chemistry, and hence catalysis, must play a major role. Most current studies of catalysts and catalysis employ a combination of physical methods, imaging techniques and spectroscopy to provide insight into the catalyst structure and function. One of the methods used is neutron scattering and this is the focus of this Perspective. Here, we show how neutron methods are being used to study reactions and processes that are directly relevant to achieving Net Zero, such as methane reforming, Fischer–Tropsch synthesis, ammonia and methanol production and utilization, bio-mass upgrading, fuel cells and CO₂ capture and exploitation. We conclude by describing some other areas that offer opportunities. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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Other

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7 pages, 787 KiB

Open AccessPerspective

Toward Computational Accuracy in Realistic Systems to Aid Understanding of Field-Level Water Quality Issues

by William A. Alexander

Physchem 2021, 1(3), 243-249; https://doi.org/10.3390/physchem1030018 - 31 Oct 2021

Cited by 1 | Viewed by 2622

Abstract

Contemplating what will unfold in this new decade and those after, it is not difficult to imagine the increasing importance of conservation and protection of clean water supplies. A worrying but predictable offshoot of humanity’s technological advances is the seemingly ever-increasing chemical load [...] Read more.

Contemplating what will unfold in this new decade and those after, it is not difficult to imagine the increasing importance of conservation and protection of clean water supplies. A worrying but predictable offshoot of humanity’s technological advances is the seemingly ever-increasing chemical load burdening our waterways. In this perspective are presented a few modest areas where computational chemistry modelling could provide benefit to these efforts by harnessing the continually improving computational power available to the field. In the acute event of a chemical spill incident, true quantum-chemistry-based predictions of physicochemical properties and surface-binding behaviors can be used to help decision making in remediating the spill threat. The chronic burdens of microplastics and perfluorinated “forever chemicals” can also be addressed with computational modelling to fill the gap between feasible laboratory experiment timescales and the much-longer material lifetimes. For all of these systems, field-level accuracy models will avail themselves as the model computational systems are able to incorporate more realistic features that are relevant to water quality issues. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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11 pages, 1012 KiB

Open AccessPerspective

Basic Residue Clusters in Intrinsically Disordered Regions of Peripheral Membrane Proteins: Modulating 2D Diffusion on Cell Membranes

by Miquel Pons

Physchem 2021, 1(2), 152-162; https://doi.org/10.3390/physchem1020010 - 19 Jul 2021

Cited by 2 | Viewed by 3515

Abstract

A large number of peripheral membrane proteins transiently interact with lipids through a combination of weak interactions. Among them, electrostatic interactions of clusters of positively charged amino acid residues with negatively charged lipids play an important role. Clusters of charged residues are often [...] Read more.

A large number of peripheral membrane proteins transiently interact with lipids through a combination of weak interactions. Among them, electrostatic interactions of clusters of positively charged amino acid residues with negatively charged lipids play an important role. Clusters of charged residues are often found in intrinsically disordered protein regions, which are highly abundant in the vicinity of the membrane forming what has been called the disordered boundary of the cell. Beyond contributing to the stability of the lipid-bound state, the pattern of charged residues may encode specific interactions or properties that form the basis of cell signaling. The element of this code may include, among others, the recognition, clustering, and selective release of phosphatidyl inositides, lipid-mediated protein-protein interactions changing the residence time of the peripheral membrane proteins or driving their approximation to integral membrane proteins. Boundary effects include reduction of dimensionality, protein reorientation, biassing of the conformational ensemble of disordered regions or enhanced 2D diffusion in the peri-membrane region enabled by the fuzzy character of the electrostatic interactions with an extended lipid membrane. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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19 pages, 1670 KiB

Open AccessPerspective

The Importance of Interphases in Energy Storage Devices: Methods and Strategies to Investigate and Control Interfacial Processes

by Chiara Ferrara, Riccardo Ruffo and Piercarlo Mustarelli

Physchem 2021, 1(1), 26-44; https://doi.org/10.3390/physchem1010003 - 13 Apr 2021

Viewed by 4427

Abstract

Extended interphases are playing an increasingly important role in electrochemical energy storage devices and, in particular, in lithium-ion and lithium metal batteries. With this in mind we initially address the differences between the concepts of interface and interphase. After that, we discuss in [...] Read more.

Extended interphases are playing an increasingly important role in electrochemical energy storage devices and, in particular, in lithium-ion and lithium metal batteries. With this in mind we initially address the differences between the concepts of interface and interphase. After that, we discuss in detail the mechanisms of solid electrolyte interphase (SEI) formation in Li-ion batteries. Then, we analyze the methods for interphase characterization, with emphasis put on in-situ and operando approaches. Finally, we look at the near future by addressing the issues underlying the lithium metal/electrolyte interface, and the emerging role played by the cathode electrolyte interphase when high voltage materials are employed. Full article

(This article belongs to the Special Issue Physical Chemistry Perspectives for the New Decade)

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