Effect Of Cations Research Articles

The effect of different exchangeable cations on the CO2 adsorption capacity of Laponite RD®

The effect of different exchangeable cations on the CO₂ adsorption capacity of Laponite RD^®

Effect of Divalent Cations on Polarity and Hydration at the Lipid/Water Interface Probed by 4-Aminophthalimide-Based Dyes.

The ion binding to the lipid/water interface can substantially influence the structural, functional, and dynamic properties of the cell membrane. Despite extensive research on ion-lipid interactions, the specific effects of ion binding on the polarity and hydration at the lipid/water interface remain poorly understood. This study explores the influence of three biologically relevant divalent cations─Mg2+, Ca2+, and Zn2+─on the depth-dependent interfacial polarity and hydration of zwitterionic DPPC lipid in its gel phase at room temperature. To measure these depth-dependent properties, we use a series of solvatochromic fluorescent probes synthesized based on 4-aminophthalimide with varying alkyl chain lengths (4AP-Cn; n = 5, 7, and 9). Employing steady-state fluorescence experiments and all-atom molecular dynamics (MD) simulations, we quantify changes in interfacial polarity and hydration induced by the cations binding to the lipid/water interface. Our results reveal that Zn2+ induces a significant blue shift in the fluorescence spectra of all 4AP-Cn dyes, indicating a marked decrease in local polarity (ETN ≤ 0.05) at the lipid/water interface compared to Mg2+ and Ca2+, which results in a higher polarity (ETN ≥ 0.2). The depth-dependent fluorescence spectra of dyes at the interface in the presence of Mg2+ and Ca2+ remain similar to those in the absence of cations, with only a minor red shift observed for Mg2+, implying a slight hydration effect. MD simulations show that cations primarily bind to the headgroup and glycerol regions of lipid. Simulations also reveal that Zn2+ causes substantial dehydration at the lipid/water interface, as detected by the 4AP-Cn dyes, while Mg2+ and Ca2+ have less pronounced effects, with only slight hydration induced by Mg2+. This study highlights the distinct positional effects of cations probed by 4AP-Cn probes at the lipid-water interface, underscoring the potential of 4AP-Cn dyes for monitoring depth-dependent changes in membrane properties induced by external agents or environmental conditions.

Clay-catalyzed ozonation of Norfloxacin - Effects of metal cation and degradation rate on aqueous media toxicity towards Lemna minor.

Norfloxacin was ozonized in aqueous montmorillonite suspensions and the resulting toxicity on Lemna minor was investigated for understanding the impact of natural partial oxidation of antibiotics on clay-containing ecosystems. Ion-exchanged montmorillonites (Mt) were used as catalysts because of their large occurrence in soils and aquatic media, while Lemna minor, an aquatic macrophyte is regarded as a bioindicator highly responsive to ecotoxicity change in the environment. NOF solutions exhibit intrinsic toxicity on L. minor expressed in terms of fresh mass, frond number, chlorophyll content and production of reactive oxygen species. This toxicity was found to trigger through oxidative stress and was enhanced by ozonation. UV-Vis spectrophotometry and liquid chromatography coupled to mass spectrometry (LC-MS) showed that the toxicity specifically evolves in time according to the clay exchangeable cations, oxidation advancement and derivatives distribution, and confirmed the unavoidable formation of hydroxylated and acidic intermediates. The cleavage of the phenyl and pyridinyl groups appear to occur even in non-catalytic ozonation and generate potentially more toxic derivatives than the parent molecule with excessive oxidative stress and changes in the distribution of the photosynthetic pigments. Addition of Fe(II)Mt and Cu(II)Mt induced a more effective ozonation with, but with much less toxicity with Fe2+ exchanged Mt catalyst. This research provides valuable insights into the environmental fate of antibiotics under aerobic conditions, and allows understanding their impact evolution on biodiversity, envisaging strategies targeting optimized water treatments with complete mineralization of organic pollutants.

Understanding the Role of Potential and Cation Effect on Electrocatalytic CO2 Reduction in All-Alkynyl-Protected Ag15 Nanoclusters.

Atomically precise metal nanoclusters (NCs) have emerged as an intriguing class of model catalysts for electrochemical CO2 reduction reactions (CO2RR). However, the interplay between the interface environment (e.g., potential, cation concentration) and electron-proton transfer (ET/PT) kinetics─particularly in alkynyl-protected metal NCs─remains poorly understood. Here, we combined first-principles simulations and electrochemical experiments to investigate the role of potential and cation effect on CO2RR performance in a prototype all-alkynyl-protected Ag15(C≡C-CH3)+ cluster. Our simulations revealed that the applied reduction potential triggers the elimination of the alkynyl ligand via sequentially breaking two π-type Ag-C bonds and one σ-type Ag-C bond to expose the catalytically active Ag sites, and the barrier of the Ag-C breakage monotonically decreases with the lowering in potential. Furthermore, we show that introducing the inner-sphere Na+ ions greatly enhances *CO2 activation and promotes proton transfer to generate *COOH and *CO by forming the Na+-CO2(*COOH) complexes, while the competitive hydrogen evolution reaction (HER) from water dissociation is greatly suppressed, thus dramatically improving the selectivity of CO2 electroreduction. The electrochemical measurements further validated our predictions, where the CO Faradaic efficiency (FECO) and current density (jCO) show a pronounced dependence on the Na+ concentration. At an optimal concentration of 0.1 M NaCl, FECO can reach up to ∼96%, demonstrating the crucial role of cations in promoting the CO2RR. Our findings provide vital insights into the atomic-level reaction mechanism of the CO2RR on alkynyl-protected Ag15 NCs and highlight the important role of potential and electrolyte cation in governing the electron/proton transfer kinetics.

Effect of Short-Chain Organic Acids, Cations and Anions on the Retention of Citicoline Under Hydrophilic Interaction Liquid Chromatography Conditions

Effect of Short-Chain Organic Acids, Cations and Anions on the Retention of Citicoline Under Hydrophilic Interaction Liquid Chromatography Conditions

Regulated Li+ Solvation via Competitive Coordination Mechanism of Organic Cations for High Voltage and Fast Charging Lithium Metal Batteries.

Li+ solvation exerted a decisive effect on electrolyte physicochemical properties. Suitable tuning for Li+ solvation enabled batteries to achieve unexpected performance. Here, we introduced inert organic cations to compete with Li+ for combining electrolyte molecules to modulate Li+ coordination in the electrolyte. The relevance between the number of cationic sites in organic cations and the competitive solvation ability was explored. The organic cations with multiple cationic sites attracted solvent molecules and anions away from Li+ to form new solvated shell, improving the Li+ transport kinetics and desolvation process in electrolyte while enhancing electrolyte oxidation tolerance. Moreover, electrostatic shielding provided by organic cations and anion-derived robust SEI promoted uniform and rapid Li+ deposition on Li electrodes. With the positive effect of organic cations, Li||LiCoO2 (LCO) batteries showed high specific capacity (136.46 mAh g-1) at high charge/discharge rate (10 C). Furthermore, Li||LCO batteries exhibited good capacity retention (70 % after 500 cycles) at 4.6 V charge cut-off voltage. This work provides fresh insights for the optimization of electrolytes and battery performance.

Regulated Li+ Solvation via Competitive Coordination Mechanism of Organic Cations for High Voltage and Fast Charging Lithium Metal Batteries

AbstractLi+ solvation exerted a decisive effect on electrolyte physicochemical properties. Suitable tuning for Li+ solvation enabled batteries to achieve unexpected performance. Here, we introduced inert organic cations to compete with Li+ for combining electrolyte molecules to modulate Li+ coordination in the electrolyte. The relevance between the number of cationic sites in organic cations and the competitive solvation ability was explored. The organic cations with multiple cationic sites attracted solvent molecules and anions away from Li+ to form new solvated shell, improving the Li+ transport kinetics and desolvation process in electrolyte while enhancing electrolyte oxidation tolerance. Moreover, electrostatic shielding provided by organic cations and anion‐derived robust SEI promoted uniform and rapid Li+ deposition on Li electrodes. With the positive effect of organic cations, Li||LiCoO2 (LCO) batteries showed high specific capacity (136.46 mAh g−1) at high charge/discharge rate (10 C). Furthermore, Li||LCO batteries exhibited good capacity retention (70 % after 500 cycles) at 4.6 V charge cut‐off voltage. This work provides fresh insights for the optimization of electrolytes and battery performance.

Weakly Solvating Electrolytes for Safe and Fast-Charging Sodium Metal Batteries.

Electrolytes for high-performance sodium metal batteries (SMBs) are expected to have high electrode compatibility, low solvation energy, and nonflammability. However, conventional flammable carbonate ester electrolytes show high Na+ desolvation energy and poor compatibility with sodium metal anodes, leading to slow Faradaic reactions and significant degradation of SMBs. Herein, we report a weakly solvating electrolytes (WSEs) design developed by an ionized ether-induced solvent molecule polarization strategy. The steric hindrance and electron-withdrawing effect of the pyrrolidine cation weaken the solvation ability of the ionized ether and enable carbonate ester with low solvation energy through intermolecular polarization interactions. It enables WSEs with fast Na+ migration kinetics and electric-field-reinforced cationic electrode/electrolyte interface, thereby promoting the stability and reversibility of SMBs even under high-charge-rate conditions. The Na||Na3V2(PO4)3 battery with ionized ether-based WSEs exhibits a capacity retention of 83.5% with an average Coulombic efficiency (CE) of 99.69% after 500 cycles at 10C. Furthermore, the Na||Na2Fe2(SO4)3 cells maintained 92.8% capacity retention after 1000 cycles at 5C with an average CE of 99.77% at a cutoff voltage of 4.5 V. The ionized ether also eliminates the fire and safety risks associated with WSEs. This work offers valuable insights into the design of WSEs for safe and high-performance sodium metal batteries.

Erratum to: The effect of typical seawater cations on the adhesion of mussel protein Mefp-1 based on dissipative quartz crystal microbalance

Erratum to: The effect of typical seawater cations on the adhesion of mussel protein Mefp-1 based on dissipative quartz crystal microbalance

Effect of Copper and Lead Cations on Flotation Behavior of Pyrite in Alkaline Seawater

ABSTRACT In this study, pyrite flotation in seawater in the presence of Cu2+and Pb2+ and the underlying mechanisms were investigated systematically. Flotation results indicated that Cu2+ and Pb2+ increased pyrite recovery from 52.51% to 79.45% and 72.57% in weak alkaline seawater (pH 8) due to the increased surface hydrophobicity. Solution species distribution and electrochemical studies cross-confirmed that the Cu2S and Pb(OH)2 layer formed on the pyrite surface at pH 8, subsequently increasing the adsorption sites of xanthate on the pyrite surface. Differently, the pyrite flotation remained at a lower recovery of around 20% than that with the addition of 10−7–10−5 M Cu2+ and Pb2+ in strong alkaline seawater (pH 10). No activation species were adsorbed on the pyrite surface at pH 10 due to the coverage of hydrophilic precipitation on the pyrite surface, resulting in a poor floatability. This study therefore provides scientific guidelines for pyrite separation in seawater in the presence of Cu2+ and Pb2+.

On the pH-Dependence of the Hupd Peak of Pt-Group Nanoparticles

Understanding the electrochemical behavior of hydrogen adsorption at Pt-group metal surfaces, particularly in the context of non-well-defined nanoparticle surfaces, is crucial for advancing electrocatalytic applications such as the hydrogen evolution reaction (HER). This study investigates the non-Nernstian pH shifts observed for underpotential deposited Hupd-like cyclic voltammetry peaks on Pt, Ir, Pd, and Rh nanoparticles. Utilizing density functional theory calculations, we explore the potential-dependent stability of H and OH adsorbates at undercoordinated surface sites, emphasizing the role of non-ideal electrosorption valencies in these shifts. Our results support that the peaks arise predominantly from a direct H-OH replacement process and suggest the primary influence of partial charge transfer. The theoretical predictions show good agreement with experimental observations across various Pt-group metals, even on non-well-defined surfaces, and provide insights into cation-specific effects at Pt across the entire pH scale. This work not only clarifies the origin of the Hupd-like peak within the water stability region but also offers a foundation for understanding cation effects in HER kinetics, paving the way for more detailed analyses of cation type, concentration, and interfacial solvent structure.

Modulation of gel characteristics in surimi-curdlan gel system by different valence metal cations: Mechanical properties, ionic distribution and microstructure visualization.

The valence state of metal cations is a potential factor in regulating the structural properties of surimi gels. In this study, Surimi-Curdlan dual network (SCDN) gel was prepared by NaCl, KCl, CaCl2, and MgCl2, combined with the concept of dual network hydrogel. The effects of different valence metal cations on mechanical properties, water state, microstructure, protein structure and composition of SCDN gel were studied. The results showed that the monovalent metal cations conferred higher G' and G" to the SCDN gel and promoted the unfolding of the α-helix structure in the proteins, providing more binding sites for adequate binding of protein and curdlan. It also increased the compatibility of proteins and curdlan, forming a regular and tight three-dimensional network structure. The monovalent metal cations enhanced the gel's mechanical properties such as strength and hardness, and retained more water through the net-trapping effect. However, the divalent metal cation-mediated SCDN gels had low G' and G", inadequate unfolding of the protein secondary structure and the aggregates formed by each of them were dispersed in the gel system, resulting in an inhomogeneous gel structure and texture. This structural feature reduced water retention and gel strength. After comprehensive comparative analysis, K+ has the potential to replace Na+ in preparing SCDN gel. This study provides some insights into the development of sodium alternatives for the surimi gel industry.

Alkali and alkaline earth metals cation effects on the formation of akageneite in corrosion products of steel artifacts embedded in soil: a study under simulated laboratory conditions

Alkali and alkaline earth metals cation effects on the formation of akageneite in corrosion products of steel artifacts embedded in soil: a study under simulated laboratory conditions

Amplifying cation effects on high-curvature nanostructures via enhancing interfacial electric field for CO 2RR to multicarbon product

Amplifying cation effects on high-curvature nanostructures via enhancing interfacial electric field for CO ₂RR to multicarbon product

Specific cation effects on soil water infiltration and soil aggregate stability–Comparison study on variably and permanently charged soils

Improving soil hydraulic properties is one of important purposes of soil tillage. Recent studies on permanently charged soil have shown specific cation effect on soil water infiltration. In this study, specific cation effects on soil water infiltration and soil aggregate stability of both variably and permanently charged soils were comparatively examined. It was found that, specific cation effects on soil water infiltration and soil aggregate stability are quite different for permanently and variably charged soils. For the permanently charged soil, the sequence of specific cation effects on soil water infiltration was Li+ << K+ < Cs+, which was in accordance with the cation polarizability sequence of Li+ (0.029 Å3) << K+ (0.88 Å3) < Cs+ (2.56Å3); but for the variably charged soil, the sequence changed to Cs+ > Li+ > K+. Moreover, the sequence of cation concentration effect on permanently charged soil water infiltration rate (SWIR) was SWIR (0.0001 mol/L) < SWIR (0.001 mol/L) < SWIR (0.01 mol/L) < SWIR (0.1 mol/L) whereas that for the variably charged soil changed to SWIR (0.1 mol/L) < SWIR (0.0001 mol/L) ≈ SWIR (0.01 mol/L) < SWIR (0.001 mol/L). The differences of specific cation and cation concentration effects on soil water infiltration for the two soils came from those on soil aggregate stability. For permanently charged soils, soil electric field determined soil aggregate stability. However, for variably charged soils, besides soil electric field, osmotic pressure, positively charged colloids and surface reaction of metal cation may possibly play critical role in soil aggregate stability.

Mixed magnesium, cobalt, nickel, copper, and zinc sulfates as thermochemical heat storage materials

Thermochemical energy storage is an emerging technology being researched for harvesting waste heat and promoting integration of renewable energy in order to combat climate change. While many simple salts such as MgSO4⋅7H2O have been investigated thoroughly, there remains much work to be done in the domain of materials that take advantage of synergetic effects of multiple different cations located in the same crystal. To this end, a solid solution library of divalent metal sulfates of the formula M1-xM2xSO4·nH2O (M, M2 = Mg, Co, Ni, Cu, Zn) has been synthesized. Following X-ray powder diffraction to confirm phase purity, scanning electron microscopy provided insight into particle morphology. One of the most conspicuous features was the presence of star-shaped cracks in some of the materials, which may contribute to increased surface area and enhance reaction kinetics. The simultaneous thermal analysis of the mixed salt sulfates led to several conclusions. Corresponding to the high initial dehydration barrier of NiSO4⋅6H2O, incorporation of nickel into other sulfates led to lower degrees of dehydration at low temperatures. The opposite effect was observed with the addition of copper. Of great interest was the surprisingly facile dehydration of hydrated Mg0.25Zn0.75SO4, which exceeded that of both pure MgSO4⋅7H2O and ZnSO4⋅7H2O. This promising compound is one representative of three different compounds with 75 % zinc which all have the highest dehydration activity up to 100 °C of all compounds in the series of hydrates of M1-xZnxSO4·nH2O (M = Mg, Ni, Cu).

Effect of Cations Contamination on Durability of Proton Exchange Membrane Water Electrolyzer

Cation contamination in proton exchange membrane water electrolyzers (PEMWE) presents a significant challenge for industrial applications impacting both performance and durability. Common sources of cation contamination include salts present in the feed water or those resulting from corrosion of components and balance of plant systems. The cations ion-exchange with the protons in Nafion® membrane, leading to a significant reduction in proton conductivity of the membrane.1 This decrease in conductivity directly affects the performance of electrolyzers resulting in increased energy consumption, and reduction in lifetime of the PEMWE, which places a significant economic and operational barrier on commercial hydrogen production.2 The cation can accelerate the degradation of the catalyst and the membrane. However, the effect of cation on the durability are not well understood.In this work, the effects of cation contamination, originating from various sources, on the performance and durability were investigated. Specifically, we investigated cations that are present in feed water (Na+, K+, Mg2+) and metal cations (Fe2+, Ti+, Al3+, Cu2+) that are introduced as the result of corrosion of the PEMWE components. In this study, cations were introduced by soaking the catalyst coated membranes (CCMs) in a solution with a known concentration of cation. The effect of PEMWE performance as a function of the cation concentration was studied. Subsequently, accelerated stress tests (AST) were performed to evaluate how cation concentrations affect the degradation of the membrane and the catalyst.AcknowledgementThis research is supported by the U.S. Department of Energy (DOE) Hydrogen and Fuel Cell Technologies Office through the Hydrogen from Next-generation Electrolyzers of Water (H2NEW) consortium. Program manager Dave Peterson and Mackenzie Hubert.LA-UR-24-23217References(1) Li, N.; Araya, S. S.; Cui, X.; Kær, S. K. The effects of cationic impurities on the performance of proton exchange membrane water electrolyzer. Journal of Power Sources 2020, 473. DOI: 10.1016/j.jpowsour.2020.228617.(2) Becker, H.; Murawski, J.; Shinde, D. V.; Stephens, I. E. L.; Hinds, G.; Smith, G. Impact of impurities on water electrolysis: a review. Sustainable Energy & Fuels 2023, 7 (7), 1565-1603. DOI: 10.1039/d2se01517j.

Investigating the Effect of Alkali Metal Cations on Electrochemical Ammonia Oxidation Reaction on Polycrystalline Platinum Electrode

It is widely recognized that hydrogen is an appropriate fuel for the sustainable energy system because it can be utilized as an energy storage material of intermittent renewable energy sources, and it generate no environmentally harmful products after combustion. However, in region where green hydrogen production cannot follow the need, import is necessary. In this case, transportation and storage of pure hydrogen can be a problem because of the high cost of maintaining liquefied state and low amount of hydrogen in compressed gas. In this regard, ammonia has received much attention as a hydrogen carrier with advantageous properties of relatively mild condition for liquefaction, high volumetric density of hydrogen, and no carbon content. Electrochemical ammonia oxidation reaction (AOR) to extract the hydrogen has been researched as much less energy is required for electrolysis when replacing oxygen evolution reaction to the AOR in aqueous alkaline condition. But high overpotential even when the most active electrocatalyst, platinum, is used and rapid poisoning by strongly adsorbed N species inhibit the practical application. To deal with these problems, there are a lot of on-going researches with various methods and perspectives. In this study, we investigated the effect of alkali metal cations on electrochemical AOR on polycrystalline platinum electrode. With same concentration but different alkali metal cations, measured the activity of platinum was different for the AOR peak (K+ > Na+ > Li+ ≈ Cs+). The reaction kinetics were also affected, supported by the electrochemical impedance spectroscopy and Tafel slope. Also, we checked that the alkali metal cation promotes the AOR by comparing the cyclic voltammetry results with and without the cation in ammonia solution. These kinds of cation effects are also demonstrated in other electrochemical reactions including the hydrogen evolution reaction, carbon dioxide reduction reaction, nitrogen reduction reaction, and oxygen evolution reaction. Mainly, there are two explanations i) the degree of interaction between cations and water structure and reaction intermediates at the interface, ii) the local electric field between electrode and hydrated cation in electric double layer. We will present and discuss the effect of alkali metal cations on the AOR in this point of view and competitive adsorption of water, proton, hydroxide and ammonia on the platinum surface in aqueous alkaline electrolyte.

The Cations Effect on Polymer-Assisted Anti-Crystallization of Alkali Metal Salts

To realize carbon neutrality, expanding the use of electric vehicles and stationary storage batteries for renewable energy is one of the effective procedures. The demand of rapid charging and discharging of Li-ion batteries continues to grow, but to achieve this, it is essential to improve Li+ transference number (t Li) of electrolytes as well as improving ionic conductivity (σ ion)1. Molten Li salts, consisted only of ions, do not cause concentration polarization, so that high Li+ transfer numbers (t Li ~ 1) have been reported under anion-blocking condition2. Although most Li salts have high melting point (T m > 100 °C) and are crystalline solids at room temperature, molten Li salt can facilitate formation of interface between electrode and electrolyte owing to the liquid state. Recently, the addition of a small amount of polymers was found to suppress crystallization and produce supercooled liquid (Li-Deeply Supercooled Salt, Li-DSS) that is stable for a long time at room temperature. Li-DSS achieved high t Li similar to the molten Li salts. In this study, DSSs were prepared with various alkali metal salts (Li, Na, K salts) and polymer to elucidate the effects of cationic and anionic structure on the formation of DSSs. The salts consisting of alkali metal cations and perfluoroamide anions such as (fluorosulfonyl)(trifluoromethansulfonyl)amide (FTA−) and bis (fluorosulfonyl)amide (FSA−), which have a relatively low melting point and low crystallinity, were selected. For polymer, we selected poly (methyl methacrylate) (PMMA), which is an amorphous polymer and has coordination sites with alkali metal cations. We could obtain Li-, Na-, and K-DSS with the addition of a small amounts of PMMA, but the stability (lifetime) of the supercooled state was in the order Li-, K-, Na-DSS, which did not follow the order of the ionic radius. The effects of cation on the thermal properties and ionic conductivity were also discussed. Acknowledgement This study was supported by the Advanced Low Carbon Technology Research and Development Program (ALCA-Next) of the Japan Science and Technology Agency (JST). References M. Diederichsen, E. J. McShane and B. D. McCloskey, ACS Energy Letters, 2017, 2, 2563-2575.Kubota and H. Matsumoto, The Journal of Physical Chemistry C, 2013, 117, 18829-18836.

Cation Effect on the Product Selectivity of Electrochemical CO Reduction

Renewable electricity-powered reduction of CO2 (CO2R) is a promising route to upgrade CO2 to ethylene, an industrial feedstock in high demand. Compared with direct CO2 electroreduction to ethylene, CO2-CO-C2H4 tandem electrolysis is more carbon efficient, circumventing CO2 crossover and carbonate formation. However, current CO electroreduction produces a mixture of multi-carbon products (ethylene, ethanol, acetate, and propanol), and the mechanism underlying this dispersion of selectivity remains unclear.We studied the role of the microenvironment of the electrode in selectivity among C2+ products, and hypothesized that destabilizing the oxygen-containing intermediates would direct the reaction pathway toward the sole oxygen-free C2+ product, ethylene. When we explore the cations in electrolyte, we find the one with the most robust hydration shell (Li) promotes ethylene production, among C2+ products, compared to weakly hydrated cations (e.g. K). This is a distinctive trend compared to studies of activity that found reverse cation trend in jc2+. A combined study of operando Raman spectroscopy, MD simulation, and DFT calculation suggests that the strongly hydrated Li+ on the electrode surface has the greatest H2O-Ointermediate interaction and the least cation-Ointermediate interaction. This increases the difference in activation energy of the selectivity-determining step between ethylene pathway and oxygenates pathway, and hence leads to the preference of Li for hydrocarbons over oxygenates. Figure 1