Tetrapropylammonium Bromide Research Articles

An environmentally friendly deep eutectic solvent for CO2 capture

A leading cause of global warming is the increase of carbon dioxide (CO2) emissions due to anthropogenic activities which prompts an urgent need for substantial reduction. Recently, CO2 absorption in deep eutectic solvents (DESs) has attracted scientific attention, because of their adaptability compared to traditional ionic liquids and aqueous amine solutions. This study employs the heating method to synthesize DESs using tetrapropylammonium bromide (TPAB) and formic acid (Fa) with molar ratios of TPAB-Fa (1:1) and TPAB-Fa (1:2). Absorption experiments by static method quantified CO2 solubility in the DESs under varied pressures and temperatures. TPAB-Fa (1:2) at 25.0 °C was the most efficient with the CO2 solubility of 0.218. Thermodynamic modeling was performed by employing the nonrandom two liquids activity coefficient model and the Peng–Robinson equation of state for the liquid and gas phases, respectively. The Henry’s law constant was determined from experimental data. CO2 physical absorption was confirmed via nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) analyses. TPAB-Fa (1:2), as the superior DES, exhibited regeneration efficiency of 99% after five absorption/desorption cycles.

An experimental-computational study on thermodynamic properties and intermolecular interactions of binary mixtures composed of quaternary ammonium salts-based deep eutectic solvents and [ETN] or [ACN]

To deep understand the thermodynamic properties and intermolecular interactions of quaternary ammonium salts-based deep eutectic solvents (DESs), two novel DESs systems ([TPAB]:[MA] and [TBAB]:[MA]) were synthesized using tetrapropylammonium bromide ([TPAB]) or tetrabutylammonium bromide ([TBAB]) as hydrogen bond acceptor (HBA) and malonic acid ([MA]) as hydrogen bond donor (HBD). Then, the ethanol (ETN) and acetonitrile (ACN) were used to prepare four DESs + solvent mixtures. Based on experimental data of density and surface tension of these four binary mixtures, the thermodynamic parameters such as apparent molar volume (Vϕ), excess molar volume (VE), limiting apparent molar expansibility (E0ϕ), molar surface entropy (s), molar surface Gibbs energy (gs), and molar surface enthalpy (h) were calculated. At the same temperature, the calculated VE values of binary mixtures were arranged in the following sequence: [TBAB]:[MA] + [ETN] > [TPAB]:[MA] + [ETN] > [TPAB]:[MA] + [ACN] > [TBAB]:[MA] + [ACN]. Based on the radial distribution functions (RDFs) theory, this observed phenomenon was attributed to the enhanced interaction between HBA and [ETN] in the DESs + [ETN] as compared to the interaction between HBA and [ACN] in the DESs + [ACN]. The predicted surface tension values (γ(pre)) of the four binary mixtures were calculated and highly correlated with the experimental surface tension values (γ(exp)). Moreover, the Br1 atom in [TPAB], the Br2 atom in [TBAB], and the H9 atom in [MA] were selected as reference sites. The interaction strength sequence between HBD and HBA was investigated using RDFs as follows: [TBAB]:[MA] + [ACN] > [TPAB]:[MA] + [ACN] > [TBAB]:[MA] + [ETN] > [TPAB]:[MA] + [ETN]. This study can provide an important theoretical support for further utilization of quaternary ammonium salts-based DESs.

Regulating the inner Helmholtz plane with an electrophilic cation additive enabled stacked stratiform growth for highly reversible Zn anodes

Achieving consecutive flattening and dendrite-free deposition for the zinc anodes is essential to avoid internal short circuits or premature failure in the Zn-ion hybrid supercapacitor (ZHSC), which largely depends on the crystal growth during the electrocrystallization process. Herein, the tetrapropyl ammonium bromide additive was employed to reconstruct the inner Helmholtz plane (IHP) structure for manipulating the Zn deposition behavior and stabilizing the interfacial electrochemistry. Joint experimental and theoretical results show that electrophilic quaternary ammonium cations (TPA+) provoke the linkage effect after the specifical adsorption at IHP of the Zn electrode, which includes the molecular/ion distribution regulation, electrostatic shielding effect, crystallographic optimization, and solid electrolyte interphase (SEI) layer formation. The adsorbed TPA+ cations at IHP expel SO42− anions, bringing a reconfiguration of the ion/molecule distribution, which leads to a relatively uniform Zn2+ions distribution at electrode/electrolyte interface and a sluggish electroreduction reaction kinetics. Meanwhile, the electrostatic shielding effect regulates the crystallographic energetic preference of Zn deposits and induces the stratiform Zn growth and dominant Zn (002) texture. Concomitantly, the partial interfacial adsorbed TPA+ cations were electrochemically reduced to form the inorganic-organic hybrid SEI layer to further enhance the corrosion resistance and stability of the Zn electrode. Consequently, TPA+ cations mediated electrolyte enables Zn||Zn cells to exhibit a reversible plating/stripping performance for more than 2800 h. Additionally, a long-term cycling life can be obtained in the Zn||activated carbon ZHSC with this electrolyte. The electrolyte mediation strategy to realize the complementary interface effect and crystalline optimization provides promising feasibility on highly reversible Zn anodes.

Thermodynamic properties, electrochemical properties, and interaction behaviors of quaternary ammonium salts-based deep eutectic solvents

To gain a deeper understanding of the formation mechanism for quaternary ammonium salts-based deep eutectic solvents (DESs), it is of great significance to investigate the interaction between hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA), as well as their physicochemical properties. In this study, tetrapropylammonium bromide (TPAB) or tetrabutylammonium bromide (TBAB) as HBA and malonic acid (MA) as HBD with a molar ratio of 1:1 or 1:1.5 were to synthesize four DESs of [TPAB]:[MA]-1, [TPAB]:[MA]-1.5, [TBAB]:[MA]-1 and [TBAB]:[MA]-1.5. The thermodynamic properties, electrochemical properties, and interaction behaviors of these DESs were investigated. The thermodynamic parameters of the standard entropy, lattice energy, molar refraction, molar polarization, and molar electrical conductivity for all DESs were calculated in terms of the Glasser’s classical theory, the molar surface Gibbs energy definition, the molar electrical conductivity definition, and Lorentz-Lorenz equation. Through linear scanning curve tests based on the three-electrode method, electrochemical potential windows (EPW) of all DESs were significantly higher than 2 V. Furthermore, according to DFT calculation and COSMO-RS theoretical model, the sequence of interaction strength for quaternary ammonium salts-based DESs was arranged as follows: [TBAB]:[MA]-1 > [TPAB]:[MA]-1 > [TBAB]:[MA]-1.5 > [TPAB]:[MA]-1.5. These fundamental theoretical studies help to provide significant theoretical reference value for the design of DESs with special properties, and promote the application range of DESs.

Dynamic insights of volumetric and viscometric exploration of Surfactant-QAs behavior in aqueous medium at varied temperatures; molecular docking and antimicrobial perspectives“

Using density (ρ), sound speed (u), viscosity (η), molecular docking and antimicrobial study analyses, this work examined the intermolecular interactions that occur between Quaternary ammonium salts (QAs) (0.005, 0.010, 0.015 molkg−1) and cationic surfactant CTAB (Cetyltrimethylammonium bromide) in aqueous solutions at 298.15 K to 313.15 K at an interval of 5 K. The Quaternary ammonium salts taken are: Tetraethylammonium bromide (TEAB), Tetra propylammonium bromide (TPAB), and Tetrabutylammonium bromide (TBAB). To comprehend and deduce the interactions, apparent molar volumes (Vϕ), apparent molar isentropic value (κS,ϕ), isentropic compressibility (κS), and acoustical parameters (Lf),(RA),(Z) and ([U]) values have been computed using the measured (ρ) and (u) data whereas relative viscosity (ηr) and viscous relaxation time (τ) values have been deduced from viscosity data. These parameters collectively provide a comprehensive understanding of the structural rearrangement of amphiphilic molecules at the interface and the relative contributions of hydrophobic and electrostatic interactions between the surfactant and aqueous solutions of QAs. Additionally, both molecular docking and antimicrobial investigations have also been performed; molecular docking facilitated the examination of interactions between ligands and proteins. Whereas, antimicrobial studies help to evaluate the impact of gram-negative bacteria (S. typhi, P. aeruginosa) and gram-positive bacteria (S. aureus, B. cereus) on CTAB in the presence of aqueous solutions containing TBAB.

Synthesis of clay/Fe/ZSM-5 composite membrane for chromium (vi) removal from aqueous media and its electrochemical performance

The present study explores the potential use of a Clay/Fe/ZSM-5 zeolite membrane as an effective platform for Chromium (VI) filtration. The raw clay sourced from Wadi Haqil Ras Al-Khaimah-UAE was utilized for fabricating the clay support sintered at 1000°C. Clay powder with a granulometry range of 125 µm ≤ Φ ≤ 250 µm, was obtained through crushing and sieving with ASTM sieves and used to prepare the clay support. The Fe/ZSM-5 zeolite was synthesized via the hydrothermal method, using tetrapropylammonium bromide (TPABr) as an organic structure-directing template. The characterization of both the clay support sintered at 1000°C and Fe/ZSM-5 zeolite membrane was conducted through various techniques, including XRD, FTIR, FE-SEM coupled with EDS, and XPS analysis. Notably, the support exhibited a relatively high deionized water flux, stabilizing at 140 L.m−2.h−1 after 120 min of operation, indicating excellent permeability. FE-SEM observations confirmed that Fe/ZSM-5 consisted primarily of granular particles with an orthorhombic crystal lattice, aligning with its crystallinity demonstrated by XRD analysis. The filtration tests for Cr(VI) solutions, conducted using a flow loop designed for cross-flow filtration, demonstrated retention rates of 23 % and 40 % for the clay support and Fe/ZSM-5 zeolite membrane, respectively, after a working time of 120 min. These results suggest the potential of Fe/ZSM-5 zeolite as an effective alternative adsorbent for removing Cr(VI) from wastewater, showcasing outstanding performance in this application. The Clay support and Fe/ZSM-5 zeolite membrane materials were used as electrodes for cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in [Fe(CN)6]3-/4-/0.1 M KCl solution, and Fe/ZSM-5 zeolite membrane material exhibited high electrochemical charge transfer compared to the clay support material.

Lignocellulosic waste biosorbents infused with deep eutectic solvents for biogas desulfurization

This paper introduces an innovative method for treating biogas streams, employing lignocellulosic biosorbents infused with environmentally friendly solvents known as deep eutectic solvents (DES). The primary focus of this study was the elimination of volatile organosulfur compounds (VSCs) from model biogas. Biosorbents, including energetic poplar wood, antipka tree, corncobs, and beech wood, were used, each with varying levels of lignin and hemicellulose content. The selection of the DES with the greatest potential for VSC removal was carried out using COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) modeling. The chosen DES consisted of quaternary ammonium salts and glycols, specifically, tetrapropylammonium bromide and 1,2-hexanediol (1:3). The physicochemical properties of the new DES, such as the viscosity, density, and melting point, were evaluated. The biosorbents were treated with the selected DES after shredding, purifying, and sieving. Comprehensive analysis techniques, including thermogravimetric analysis, scanning electron microscopy, and X-ray diffraction, were employed on the modified biosorbents both before and after modification. The subsequent step involved the adsorption of VSCs from biogas. The results of this study demonstrated the superior performance of a novel sorbent based on corn cob modified by DES compared to commercially available alternatives. The sorption capacity ranged from 103.8 to 112.1 mg/g for various VSCs. The adsorption process using the new biosorbent can be described by the pseudo second order kinetic model, as well as the Yoon-Nelson and Adams-Bohart models. The high efficacy of the VSCs removal was attributed to the concurrent operation of the absorption and adsorption processes. The resulting sorbent was also characterized by its ability to regenerate repeatedly without significant loss of sorption capacity of the new sorbents.

Digital colorimetric detection of ammonium in water samples after microextraction procedure using deep eutectic solvent, based on DLLME method

In this study, we have presented a simple, cost-effective, and efficient method for quantifying ammonium ions based on digital colorimetry using a smartphone. Firstly, ammonium ions are converted into a yellow-colored derivative in an alkaline medium in the presence of acetylacetone and formaldehyde. Then, the colored compound is extracted using the dispersive liquid–liquid microextraction (DLLME) technique and its color intensity was measured using a smartphone as RGB Color Detector. For this purpose, a novel deep green eutectic solvent including tetrapropylammonium bromide (TPABr) and 3-methyl-1-butanol (isoamyl alcohol) was employed, with a molar ratio of 1:6. The impact of key variables on the derivatization and microextraction processes, including solution pH, concentration of acetylacetone and formaldehyde, temperature, reaction time, and extraction solvent volume, was thoroughly investigated and optimized. In the optimized conditions, the method was found to be linear in the range of 0.15–5.00 µg mL−1 with a limit of detection of 0.05 µg mL−1 (S/N = 3). Moreover, the proposed method was successfully applied for the determination of ammonium ions in environmental water samples, fish pond, and aquarium water samples, with recoveries ranging from 94.7 to 106.7 %.

Self-synthesis and performance analysis of a Cu-Fe composite ZSM-5 zeolitic catalyst for NOx reduction and particulate matter removal using NH3 SCR

The NH3-SCR has gained widespread usage due to its exceptional denitrification efficiency. It achieves high nitrogen oxides (NOx) reduction rates within the temperature range of 300⁰C to 400℃. Nonetheless, most of the catalyst have a limited temperature range for effective NOx removal applications. For sustainable utilization of common combustion units, it has become essential to develop a catalyst which can provide a broader spectrum of temperature range for NOx reduction. This study is thus aimed to enhance the structure of ZSM-5 zeolite molecular sieves using tetrapropylammonium bromide. Copper and iron ions (total 3% weight) were incorporated to boost the reaction at temperatures of 180⁰C, 250⁰C and 320⁰C. The overall efficiency of NOx removal was above 81%, highest being 97.6%. The carrier significantly impacts the NOx conversion rate with increased copper ion content in the samples at medium and low temperatures. The Particulate Matter removal efficiency ranged from 90.1% to 93.1%.

Pd-loaded hierarchical titanosilicalite-1 catalysts on CO2 cycloaddition with epoxides: Experimental and DFT investigations

This work presents the synthesis of Pd-loaded microporous titanosilicalite-1 (Pd/TS-1) and Pd-loaded hierarchical titanosilicalite-1 (Pd/HTS-1) with abundant mesopores (2–30 nm) inside the framework via hydrothermal method using polydiallydimethyl ammonium chloride as the non-surfactant mesopore template. XRD, N2 sorption, FT-IR, FESEM-EDX, TEM, XPS, and DR-UV techniques were used to characterize the morphological and physicochemical properties of the synthesized materials. These materials were tested as heterogeneous catalysts, along with tetrapropylammonium bromide as co-catalyst, for cycloaddition reactions of CO2 with epoxides to produce cyclic carbonates. It was found that the epoxide conversions were influenced by acidity and pore accessibility of the catalysts. Using Pd/HTS-1 facilitated bulky substrates to access active sites, resulting in higher conversions than Pd/TS-1. Over 85 % conversions were achieved for at least five consecutive cycles without significant loss in catalytic activity. The interaction between the Pd active surfaces and epichlorohydrin (ECH) was further studied by DFT calculations. The existence of Pd(200) was more influential on adsorbing epichlorohydrin (ECH) and subsequent formation of dissociated ECH (DECH) intermediate than Pd(111) surface. However, Pd(111) was dominant in enhancing the activity of DECH species for capturing CO2. Therefore, the co-existence of Pd(200) and Pd(111) surfaces was needed for cycloaddition of CO2 with ECH.

Catalytic reforming of cellulose pyrolysis volatiles over hierarchical HZSM-5: Mechanism of a protective effect of tetrapropylammonium (TPA+) during alkali treatment

A series of HZSM-5 with hierarchical pores was obtained by using a modified NaOH treatment method. This modification incorporated the use of tetrapropylammonium bromide. Furthermore, their catalytic performance for reforming of cellulose pyrolysis volatiles at 600 °C was investigated. TPAB-assisted alkali treatment increased the mesoporosity, relative crystallinity, and surface integrity of ZSM-5. Additionally, a significant portion of the acidic sites was preserved. The 0.1TPAB-0.2AT, treated with 0.1 M TPAB and 0.2 M NaOH, yielded the highest light aromatics at 156.9 mg/g. The coking resistance of the catalyst was also improved. Tetrapropylammonium (TPA+) achieves surface protective desilication by selectively adsorbing Si(0Al) on the zeolite. Subsequently, the continuous adsorption of TPA+ leads to mesopore formation within the zeolite. This continuous restriction on desilication limits the increase in mesopore volume, resulting in a relatively abundant and uniform distribution of smaller mesopores on ZSM-5. This mechanism holds promise for future synthesis of highly mesoporous ZSM-5.

Catalytic activity of two-dimensional cobalt-ZIF catalyst for NaBH4 hydrolysis

In this work, cobalt-ZIF catalysts were synthesized by water-based synthesis methods. Various hydrogen bond acceptor (tetramethylammonium bromide (TMAB), tetraethylammonium bromide (TEAB), tetrapropylammonium bromide (TPAB), tetrabutylammonium bromide (TBAB) and trimethylphenylammonium bromide (TMPAB)) were co-added during cobalt-ZIF catalyst synthesis procedures to promote the deprotonation of 2-methyl imidazole and the deprotonated 2-methyl imidazole was then further coordinated with cobalt ion to form a ZIF framework. Co-addition of TMPAB during synthesis resulted in 3D imperfect rhombic dodecahedrals with high surface area (432.3 m2/g), while, the rest of used hydrogen bond acceptors (TMAB, TEAB, TPAB and TBAB) provided 2D ZIF-L structure with relatively small surface area and pore volume. All synthesized cobalt-ZIF with different structures and morphologies were used as a catalyst for H2 generation by NaBH4 hydrolysis reaction. It was found that all 2D cobalt-ZIF structures exhibited higher hydrogen production rate than that of the 3D imperfect rhombic dodecahedral structure. This can be explained by the cushion-shaped cavity of a two-dimensional framework exhibiting higher flexibility which can promote more diffusion of reactants than the tetrahedral structure of a 3D-framework. X-ray absorption spectroscopy was used to investigate the electronic state of cobalt and to monitor the changing of cobalt probe atom during hydrolysis reaction. The electronic state of cobalt for all catalysts was Co2+ with the same tetrahedral symmetry. The lowering of pre-edge peaks of cobalt K edge XANES spectra during hydrolysis reaction indicated to distortion of the symmetry which is related to the reduction of the catalytic performance.

Hydrothermal synthesis of kaolin-based ZSM-5 zeolite: Effect of synthesis parameters and its application for bioethanol conversion

In petrochemical applications, improving the catalytic activity and stability of Zeolite as a cutting-edge material has gained research interest. Herein, a local South African clay as a source of high silica and alumina with an organic template of tetrapropylammonium bromide (TPABr) was synthesized hydrothermally. The study then examined the effect of crystallization temperature (120–180 °C), crystallization time (24–96 h) and ageing time (0–48 h) on the crystallinity, surface morphology and functional group of the Kaolin-based ZSM-5 Zeolite formed. Characterization results by X-ray diffraction, scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed the hydrothermal synthesis of the crystalline powder was successful. The XRD revealed the highest intensity at ∑5 with the most intense peaks at 2Ѳ° and a relative crystallinity from 74.6% to 76.66% at the temperature of 180°C and 48 h of ageing and crystallization time of sampled powder. The crystals' growth and pore structure (openings of 5–5.5 Å) was affirmed by the SEM results. Likewise, the BET revealed the surface area (146.15 m2/g), pore volume (0.056 cm3/g) and pore size (59.12 Å). The FTIR spectra vibration within the wavenumber from 545 to 1224 cm−1 also confirmed the sharpness of the beta and pentasil index peaks. Moreso, the bioethanol conversion at the temperature of 180°C over the synthesized ZSM-5 catalyst yielded 2.03% H2, 1.03% CH4, 37.07% C2H4, and 62.4% liquids. This study has demonstrated the synthesized Kaolin-based ZSM-5 Zeolite has the potential for industrial decomposition of ethanol with good catalyst stability.

A Radical Pathway and Stabilized Li Anode Enabled by Halide Quaternary Ammonium Electrolyte Additives for Lithium‐Sulfur Batteries

AbstractPassivation of the sulfur cathode by insulating lithium sulfide restricts the reversibility and sulfur utilization of Li−S batteries. 3D nucleation of Li2S enabled by radical conversion may significantly boost the redox kinetics. Electrolytes with high donor number (DN) solvents allow for tri‐sulfur (S3⋅−) radicals as intermediates, however, the catastrophic reactivity of such solvents with Li anodes pose a great challenge for their practical application. Here, we propose the use of quaternary ammonium salts as electrolyte additives, which can preserve the partial high‐DN characteristics that trigger the S3⋅− radical pathway, and inhibit the growth of Li dendrites. Li−S batteries with tetrapropylammonium bromide (T3Br) electrolyte additive deliver the outstanding cycling stability (700 cycles at 1 C with a low‐capacity decay rate of 0.049 % per cycle), and high capacity under a lean electrolyte of 5 μLelectrolyte mgsulfur−1. This work opens a new avenue for the development of electrolyte additives for Li−S batteries.

A Radical Pathway and Stabilized Li Anode Enabled by Halide Quaternary Ammonium Electrolyte Additives for Lithium-Sulfur Batteries.

Passivation of the sulfur cathode by insulating lithium sulfide restricts the reversibility and sulfur utilization of Li-S batteries. 3D nucleation of Li2 S enabled by radical conversion may significantly boost the redox kinetics. Electrolytes with high donor number (DN) solvents allow for tri-sulfur (S3 ⋅- ) radicals as intermediates, however, the catastrophic reactivity of such solvents with Li anodes pose a great challenge for their practical application. Here, we propose the use of quaternary ammonium salts as electrolyte additives, which can preserve the partial high-DN characteristics that trigger the S3 ⋅- radical pathway, and inhibit the growth of Li dendrites. Li-S batteries with tetrapropylammonium bromide (T3Br) electrolyte additive deliver the outstanding cycling stability (700 cycles at 1 C with a low-capacity decay rate of 0.049 % per cycle), and high capacity under a lean electrolyte of 5 μLelectrolyte mgsulfur -1 . This work opens a new avenue for the development of electrolyte additives for Li-S batteries.

Salt effects on the reactivity for ligand substitution reactions of [Ru(CN)5OH2]3− anion with two naphthalene substituted ligands (nitroso‐R‐salt and α‐nitroso‐β‐naphthol) in presence of Tetrapropylammonium bromide (Pr4NBr) and Sodium chloride (NaCl)

AbstractThe kinetics of the ligand exchange reaction between aquapentacyanoruthenate(II) [Ru(CN)5OH2]3− ion and naphthalene substituted ligands [α‐nitroso‐β‐naphthol (αNβN), and nitroso‐R‐salt (NRS)] has been studied in aqueous salt solutions of sodium chloride (NaCl) or tetrapropylammonium bromide (Pr4NBr) salt. The kinetics was monitored spectrophotometrically at 525 nm corresponding to the λmax of reddish‐brown‐colored substituted products, [Ru(CN)5(αNβN)]3− or [Ru(CN)5(NRS)]3−. Increasing the ionic strength of the reaction mixture using NaCl, exerted a negative salt effect on the rate of formation of naphthalene‐substituted products. At the same time, an increment in the concentration of Pr4NBr imparted a positive salt effect on the reaction. The observed rate constant (kobs) exhibits linear increment with respect to the concentration of NRS or αNβN while remaining invariant with variation in [Ru(CN)5OH2]3−. The computed activation parameters for NRS (∆H# = 24.55 kJ mol−1, Ea = 27.03 kJ mol−1, ∆G# = 87.83 kJ mol−1, and ∆S# = – 212.5 J K−1 mol−1) and αNβN ((∆H# = 17.33 kJ mol−1, Ea = 19.81 kJ mol−1, ∆G# = 87.87 kJ mol−1, and ∆S# = – 236.7 J K−1 mol−1) also support the proposed mechanism.

Unveiling the soluting-out effect of amino acids (S(+)-serine and S(-)-proline) on aqueous solutions of tetraalkylammonium bromide salts

The aqueous ternary systems composed of amino acid and tetraalkylammonium bromide (TAAB) were subjected to vapor–liquid and solid–liquid equilibria (VLE and SLE) studies to investigate the soluting effects in these systems. The amino acids used are S(+)-serine and S(-)-proline, and the TAABs are tetramethylammonium bromide (TMAB), tetrapropylammonium bromide (TPAB), and tetrabutylammonium bromide (TBAB). The water iso-activity curves obtained from the VLE measurements reveal the negative deviations from the linear isopiestic relation (LIR), indicating unfavorable amino acid – TAAB interactions in aqueous media. The incompatibility between amino acid and TAAB leads to solid–liquid demixing above critical concentrations. The results of SLE experiments demonstrate reducing the water-solubility of TAABs in the presence of the amino acids, while the water-solubility of amino acids doesn’t significantly change with the addition of TAABs. According to both VLE and SLE measurements, the amino acids play the role of the soluting-out agents in the investigated systems. The soluting-out strength increases with increasing the hydrophilic character of amino acids and the hydrophobic character of TAABs.

Redoxless Electrochemical Capacitance Spectroscopy for Investigating Surfactant Adsorption on Screen-Printed Carbon Electrodes

Electrochemical impedance spectroscopy (EIS) is a sensitive analytical method for surface and bulk properties. Classical EIS and derived electrochemical capacitance spectroscopy (ECS) with a redox couple are label-free approaches for biosensor development, but doubts arise regarding interpretability when a redox couple is employed (redox EIS) due to interactions between electroactive probes and interfacial charges or forced potential. Here, we demonstrated redoxless ECS for directly determining surfactant adsorption on screen-printed carbon electrodes (SPCEs), validated through a simulation of equivalent circuits and the electrochemistry of electronic dummy cells. Redoxless ECS provides excellent capacitance plot loci for quantifying the interfacial permittivity of di-electric layers on electrode surfaces. Redoxless ECS was compared with redox EIS/ECS, revealing a favorable discrimination of interfacial capacitances under both low and high SDS coverage on SPCEs and demonstrating potential for probeless (reagentless) sensing. Furthermore, the proposed method was applied in an electrolyte without a redox couple and bare electrodes, obtaining a high performance for the adsorption of surfactants Tween-20, Triton-X100, sodium dodecyl sulfate, and tetrapropylammonium bromide. This approach offers a simple and straightforward means for a semi-quantitative evaluation of small molecule interactions with electrode surfaces. Our proposed approach may serve as a starting point for future probeless (reagentless) and label-free biosensors based on electrochemistry, eliminating disturbance with surface charge properties and minimizing forced potential bias by avoiding redox couples. An unambiguous and quantitative determination of physicochemical properties of biochemically recognizable layers will be relevant for biosensor development.

Solid Interhalogen Compounds with Effective Br0 Fixing for Stable High‐energy Zinc Batteries

AbstractThough massive efforts have been devoted to exploring Br‐based batteries, the highly soluble Br2/Br3− species causing rigorous “shuttle effect”, leads to severe self‐discharge and low Coulombic efficiency. Conventionally, quaternary ammonium salts such as methyl ethyl morpholinium bromide (MEMBr) and tetrapropylammonium bromide (TPABr) are used to fix Br2 and Br3−, but they occupy the mass and volume of battery without capacity contribution. Here, we report an all‐active solid interhalogen compound, IBr, as a cathode to address the above challenges, in which the oxidized Br0 is fixed by iodine (I), thoroughly eliminating cross‐diffusing Br2/Br3− species during the whole charging and discharging process. The Zn||IBr battery delivers remarkably high energy density of 385.8 Wh kg−1, which is higher than those of I2, MEMBr3, and TPABr3 cathodes. Our work provides new approaches to achieve active solid interhalogen chemistry for high‐energy electrochemical energy storage devices.

Solid Interhalogen Compounds with Effective Br0 Fixing for Stable High-energy Zinc Batteries.

Though massive efforts have been devoted to exploring Br-based batteries, the highly soluble Br2 /Br3 - species causing rigorous "shuttle effect", leads to severe self-discharge and low Coulombic efficiency. Conventionally, quaternary ammonium salts such as methyl ethyl morpholinium bromide (MEMBr) and tetrapropylammonium bromide (TPABr) are used to fix Br2 and Br3 - , but they occupy the mass and volume of battery without capacity contribution. Here, we report an all-active solid interhalogen compound, IBr, as a cathode to address the above challenges, in which the oxidized Br0 is fixed by iodine (I), thoroughly eliminating cross-diffusing Br2 /Br3 - species during the whole charging and discharging process. The Zn||IBr battery delivers remarkably high energy density of 385.8 Wh kg-1 , which is higher than those of I2 , MEMBr3 , and TPABr3 cathodes. Our work provides new approaches to achieve active solid interhalogen chemistry for high-energy electrochemical energy storage devices.