Hydrogen Cations Research Articles

Role of A-Site Cation Hydrogen Bonds in Hybrid Organic-Inorganic Perovskites: A Theoretical Insight.

Hybrid organic-inorganic halide perovskites (HOIPs) have garnered a significant amount of attention due to their exceptional photoelectric conversion efficiency. However, they still face considerable challenges in large-scale applications, primarily due to their instability. One key factor influencing this instability is the lattice softness attributed to the A-site cations. In this study, we investigated the effects of four different A-site cations (MA, FA, EA, and GA) on the lattice softness of perovskites by using a combination of ab initio molecular dynamics and first-principles calculations. Our results demonstrate that an increase in the number of hydrogen bonds for A-site cations correlates with enhanced lattice and atomic fluctuations, resulting in a reduction in the bulk modulus and an increase in the lattice softness. The strength of hydrogen bonding of the A-site cation increases the rotational energy barrier of the cation, along with the formation energy and kinetic coupling between the A-site cation and the [PbI6]4- octahedron. Consequently, this increases the lifetime of hydrogen bonding and enhances the rigidity of the perovskite lattice. Notably, we found that EA cations, which exhibit stronger hydrogen bonding with fewer total hydrogen bonds, can limit the rotation of the A-site cation, inhibit the rocking motion of the [PbI6]4- octahedron, and thereby increase the rigidity of the inherently soft perovskite lattice, ultimately enhancing the stability of the material. Our findings elucidate the effect of hydrogen bonding in A-site cations on the lattice softness of perovskites, providing valuable theoretical insights for the design of more stable HOIPs.

Rapid In Situ Preparation of Conductive Graphite-like Films on Polymer Surfaces via Hydrogen Plasma Technology.

Many special polymer materials with high strength, low density, and high processability have been developed for the substitution of metal products in recent years; however, their electrical insulation properties sometimes limit their application in medicine, electronics, and aerospace fields. Constructing a conductive layer on polymers may be a promising strategy for conquering these problems, but simply obtaining a high-quality conductive layer remains a challenge. Here, we develop a universal strategy to in situ fabricate a conductive graphite-like film on various polymer surfaces based on a simple one-step gas plasma ion implantation method. Theoretical and experimental results confirm that the reducibility of free radicals and the electrophilicity of cations in plasma are critical for the formation of graphite-like films on polymer surfaces. Compared with argon and oxygen plasma, hydrogen plasma with strong reducing hydrogen radicals and weak electrophilic hydrogen cations can produce the highest degree of graphitization of graphite-like films. The as-prepared polymers treated by hydrogen plasma ion implantation presented good surface conductivity and reduced friction coefficient, which has great potential for application in medicine, electronics, and aerospace fields.

Deciphering the genetic basis of salinity tolerance in a diverse panel of cultivated and wild soybean accessions by genome-wide association mapping

Key messageIn a genome-wide association study involving 269 cultivated and wild soybean accessions, potential salt tolerance donors were identified along with significant markers and candidate genes, such as GmKUP6 and GmWRKY33.Salt stress remains a significant challenge in agricultural systems, notably impacting soybean productivity worldwide. A comprehensive genome-wide association study (GWAS) was conducted to elucidate the genetic underpinnings of salt tolerance and identify novel source of salt tolerance among soybean genotypes. A diverse panel comprising 269 wild and cultivated soybean accessions was subjected to saline stress under controlled greenhouse conditions. Phenotypic data revealed that salt tolerance of soybean germplasm accessions was heavily compromised by the accumulation of sodium and chloride, as indicated by highly significant positive correlations of leaf scorching score with leaf sodium/chloride content. The GWAS analysis, leveraging a dataset of 32,832 SNPs, unveiled 32 significant marker-trait associations (MTAs) across seven traits associated with salt tolerance. These markers explained a substantial portion of the phenotypic variation, ranging from 14 to 52%. Notably, 11 markers surpassed Bonferroni’s correction threshold, exhibiting highly significant associations with the respective traits. Gene Ontology enrichment analysis conducted within a 100 Kb range of the identified MTAs highlighted candidate genes such as potassium transporter 6 (GmKUP6), cation hydrogen exchanger (GmCHX15), and GmWRKY33. Expression levels of GmKUP6 and GmWRKY33 significantly varied between salt-tolerant and salt-susceptible soybean accessions under salt stress. The genetic markers and candidate genes identified in this study hold promise for developing soybean varieties resilient to salinity stress, thereby mitigating its adverse effects.

Electric Double Layer Theory of Interfacial Ionic Liquids for Capturing Ion Hierarchical Aggregation and Anisotropic Dynamics

AbstractCompared to aqueous ions, ionic liquids (ILs) consist entirely of cations and anions, and they function in energy conversion and storage owing to unique properties. Classical electric double layer (EDL) theory born a century ago gives essential insights into aqueous interfaces, whereas it fails in ILs due to overlooking ionic geometries and interactions, leaving a theoretical gap in describing IL interfaces. This study captures IL fingerprints by combining nuclear magnetic resonance experiments, quantum chemistry investigations, and first‐principles molecular simulations. Based on these findings, an EDL theory is proposed to reflect hierarchical aggregation structure and anisotropic dynamics for interfacial ILs. It involves four elements including ion geometries, ion–ion interactions, ion–wall interactions, and temperature and interfacial electric field effects. Specifically, polyatomic ions with nonuniform shapes are cornerstones for successive elements. Cation–anion non‐oxygen hydrogen bonds and cation–cation π+–π+ stacking generate bound clusters. Ion–wall adsorption causes hierarchical aggregation patterns, and cation–wall parallel stacking creates anisotropic dynamics at interfaces. Moreover, the thermal‐weakened ionic interactions and electric field‐enhanced interfacial electron transfer alter the aggregation states and dynamic properties of interfacial ILs. This theory is adaptable to various IL–wall combinations, advancing electrolyte design for next‐generation electrochemical energy devices.

Changes in the Aggregation Behaviour of Zinc Oxide Nanoparticles Influenced by Perfluorooctanoic Acid, Salts, and Humic Acid in Simulated Waters.

The increasing utilization of zinc oxide nanoparticles (ZnO-NPs) in many consumer products is of concern due to their eventual release into the natural environment and induction of potentially adverse impacts. The behaviour and environmental impacts of ZnO-NPs could be altered through their interactions with environmentally coexisting substances. This study investigated the changes in the behaviour of ZnO-NPs in the presence of coexisting organic pollutants (such as perfluorooctanoic acid [PFOA]), natural organic substances (i.e., humic acid [HA]), and electrolytes (i.e., NaCl and CaCl2) in simulated waters. The size, shape, purity, crystallinity, and surface charge of the ZnO-NPs in simulated water after different interaction intervals (such as 1 day, 1 week, 2 weeks, and 3 weeks) at a controlled pH of 7 were examined using various characterization techniques. The results indicated alterations in the size (such as 162.4 nm, 1 day interaction to >10 µm, 3 weeks interaction) and zeta potential (such as -47.2 mV, 1 day interaction to -0.2 mV, 3 weeks interaction) of the ZnO-NPs alone and when PFOA, electrolytes, and HA were present in the suspension. Different influences on the size and surface charge of the nanoparticles were observed for fixed concentrations (5 mM) of the different electrolytes. The presence of HA-dispersed ZnO-NPs affected the zeta potential. Such dispersal effects were also observed in the presence of both PFOA and salts due to their large aliphatic carbon content and complex structure. Cation bridging effects, hydrophobic interactions, hydrogen bonding, electrostatic interactions, and van der Waals forces could be potential interaction forces responsible for the adsorption of PFOA. The presence of organic pollutants (PFOA) and natural organic substances (HA) can transform the surface characteristics and fate of ZnO-NPs in natural and sea waters.

Hydrogen Evolution Reaction: Log j0 Versus Work Function Φ As Viewed from Transition State Theory As an Eyring Plot

In 1972, Trasatti correlated the log of the exchange current density (j0) for the hydrogen evolution reaction (HER) with the work functions of 31 metal electrodes to yield two parallel regression lines. [1] The lines are separated by Δ log j0 = 3. Thermodynamically, work function 𝚽 is the energy to remove an electron from a metal to infinity. Perhaps counterintuitively, platinum group metals (PGMs) with the highest 𝚽 sustain the highest j0 values.The elementary, interfacial electron transfer occurs between the electrode and adsorbed hydrogen cation and adsorbed hydrogen atom.H+ ads + e ⇌ H● ads A materials dependent rate expression is developed as follows. [2]The properties of the metal are introduced explicitly into reaction mechanism, characterized by M(e) and M(0), the metal electrode with and without the electron.M(e) + H+ ads ⇄ M(0) + H● ads Classical transition state theory (TST) characterizes the free energy of activation ΔG‡ as the energy difference between the transition state (TS) and the minimum energy of the reactants. The TS forms at equilibrium, where adsorbed hydrogen and metal electrode share the electron.M(e) + H+ ads ⇌ [M ●●● e ●●● Hads]‡ ⇌ M(0) + H● ads Electrochemical potentials set the energy difference in the products and reactant, which sets ΔG‡. Chemical potential (𝞵) difference for the metal without and with the electron define 𝚽. F𝚽 = 𝞵M(0) - 𝞵M(e) F𝚽 is further defined as a chemical free energy that that lowers ΔG‡. F𝚽 is a material specific property that is atypically specified in the rate equation. Because log j0 ∝ - ΔG‡, and chemical free energy F𝚽 lowers ΔG‡, log j0 ∝ F𝚽. Thus, j0 increases exponentially with F𝚽, so PGMs with highest 𝚽 sustain highest j0. Further, the rate expression embeds material specific property 𝚽.The classical Eyring perspective for generic rate constant k’ is k’ = A’ exp[-ΔG‡/RT]. Rate constant is typically determined by varying temperature in a plot of ln k’ versus T-1, where ln k’ = ln A’ - ΔG‡/RT. For isothermal measurements, log j0 is linear with 𝚽 because F𝚽 is a term ΔG‡ chem that is a component in the total ΔG‡. For metals, where 𝚽 > 0, F𝚽 always lowers ΔG‡ for HER; the total activation energy is lowered in proportion to F𝚽. The slopes of log j0 versus 𝚽 is proportional to 𝝰𝚽F𝚽/2.303, where partition coefficient 𝝰𝚽 characterizes ∂ΔG‡/∂𝚽. For the parallel lines in Trasatti’s plot, 𝝰𝚽 = 0.38. The intercepts are independent of 𝚽.The material specific rate expressions derived from classical TST and electrochemical potentials may provide guidance on design of electrocatalysts and provide a path to integration of classical and contemporary modeling of important reaction processes such as HER.

SnF(bipy)(H2O)]2[SnF6], a mixed-valent inorganic tin(II)-tin(IV) compound.

In the title compound, bis-[aqua-(2,2'-bi-pyridine)-fluorido-tin(II)] hexa-fluorido-tin(IV), [SnF(C10H8N2)(H2O)]2[SnF6], an ionic mixed-valent tin(II)-tin(IV) compound, the bivalent tin atom is the center atom of the cation and the tetra-valent tin atom is the center atom of the anion. With respect to the first coordination sphere, the cation is monomeric, with the tin(II) atom having a fourfold seesaw coordination with a fluorine atom in an equatorial position, a water mol-ecule in an axial position and the two nitro-gen atoms of the chelating 2,2'-bi-pyridine ligand in the remaining axial and equatorial positions. The bond lengths and angles of this hypervalent first coordination sphere are described by 2c-2e and 3c-4e bonds, respectively, all of which are based on the orthogonal 5p orbitals of the tin atom. In the second coordination sphere, which is based on an additional, very long tin-fluorine bond that leads to dimerization of the cation, the tin atom is trapezoidal-pyramidally coordinated. The tetra-valent tin atom of the centrosymmetric anion has an octa-hedral coordination. The differences in its tin-fluorine bond lengths are attributed to hydrogen bonding, as the two of the four fluorine atoms are each involved in two hydrogen bonds, linking anions and cations together to form strands.

Multiple Noncovalent Binding in the Intermediates and Products of the Reaction of <i>N,N</i>-Dimethylformamide with Bromine

Reaction of nonionic N,N-dimethylformamide (DMF) with bromine under controllable conditions leads to a number of ionic compounds, mainly to bis(N,N-dimethylformamide)hydrogen dibromobromate. Computations with DFT (ωB97xV/dgdzvp) were made for geometry, thermochemistry and electron configuration of products and supposed intermediates. Two labile particles [bis(N,N-dimethylformamide)hydrogen cation and dibromobromate-anion] form stable highly conductive ionic liquid that can be distilled in vacuo without losses or decomposition. A number of molecular complexes of DMF with bromine and water presumed to be intermediates of this reaction. It is a set of halogen and hydrogen bonding that provide an intramolecular binding in these complexes.

Exploring the conformational dynamics and key amino acids in the CD26-caveolin-1 interaction and potential therapeutic interventions.

This study aimed to decipher the interaction between CD26 and caveolin-1, key proteins involved in cell signaling and linked to various diseases. Using computational methods, we predicted their binding conformations and assessed stability through 100 ns molecular dynamics (MD) simulations. We identified two distinct binding conformations (con1 and con4), with con1 exhibiting superior stability. In con1, specific amino acids in CD26, namely GLU237, TYR241, TYR248, and ARG147, were observed to engage in interactions with the F-J chain of Caveolin-1, establishing hydrogen bonds and cation or π-π interactions. Meanwhile, in con4, CD26 amino acids ARG253, LYS250, and TYR248 interacted with the J chain of Caveolin-1 via hydrogen bonds, cation-π interactions, and π-π interactions. Virtual screening also revealed potential small-molecule modulators, including Crocin, Poliumoside, and Canagliflozin, that could impact this interaction. Additionally, predictive analyses were conducted on the potential bioactivity, drug-likeness, and ADMET properties of these three compounds. These findings offer valuable insights into the binding mechanism, paving the way for new therapeutic strategies. However, further validation is required before clinical application. In summary, we provide a detailed understanding of the CD26 and caveolin-1 interaction, identifying key amino acids and potential modulators, essential for developing targeted therapies.

METROLOGICAL STUDY OF THE EFFECT OF TEMPERATURE ON THE DISSOCIATION OF ACETIC ACID

This article is devoted to the study of the dissociation reaction of acetic acid at a temperature change in the range from room (20 °C) to 75 °C. In the course of research, the methods were considered, the classification of the considered methods was carried out, and the methodology of the experiments was formulated. The selected technique reflects the express measurement of the hydrogen pH indicator using a portable pH-meter. Experiments were carried out in laboratory conditions – Lincoln Park, Chicago, USA. Acetic acid with a concentration of 6 mol/l was chosen as the basis. By adding a distilled water, a base concentration of 1 mol/l was obtained. Nodal temperature points were selected for measurements (four points in the temperature range of 20 °C – 75 °C); five experimental samples of acetic acid (1 mol/l) were formed; the analysis of the measurement results at nodal points was carried out for the accuracy of the measurement results of five test samples of acetic acid using first- and second-order statistical moments (mathematical expectation and variance); accuracy characteristics of experimental data (instrumental and methodical errors) were estimated. Research samples (acetic acid samples) were brought to the nodal points with a positive temperature gradient using a steam bath. The measurement error estimate was determined by the accuracy class of the device and was 0.1%. The obtained pH values were converted to the number of hydrogen cations, followed by the determination of the degree of dissociation and the dissociation constant. These determinations were carried out under the condition of ensuring chemical equilibrium. The nature of the behavior of the degree and constant of dissociation when the temperature of the test samples changes is clearly non-linear. In the course of research, the main measurement errors were established, the main of which is the nonlinearity of the transformation. Quantitative values of nonlinearity errors were determined by the method of measurements with multiple observations using the Student's correction factor. The article provides conclusions based on the results of research and presents the prospects for temperature correction of pH-meters to eliminate the temperature component of the error of pH-meters.

Round-the-Clock and Continuous Generation of Hydrogen and Oxygen

The main methods of industrial hydrogen production are: steam restructuring of methane and natural gas; coal gasification; biotechnology; water electrolysis. The most efficient method for producing pure hydrogen and oxygen is to produce pure hydrogen and oxygen in a photoelectrochemical cell. A photoelectrochemical cell produces hydrogen and oxygen directly from solar energy. In a photoelectrochemical cell, a combined anode, made from silicon semiconductor and metal mesh with large cells, submerged in water electrolyte solution, agitated by four photons of light, forms an oxygen molecule, which in the form of a gas bubble lifts from the surface of anode to the free surface of the water electrolyte solution. Two hydrogen cations, formed because of the dissociation of water, reaching the cathode, form a gaseous hydrogen molecule, which, turn into an electrolysis bubble, lifts from surface of cathode to the free surface of the water electrolyte solution. The article presents a new method for round-the-clock and continuous generation of hydrogen and oxygen, using a developed photoelectrolyzer-generator, taking a horizontally located combine anode, made from silicon semiconductor and metal mesh with large cells and burnt graphite cathode (electrolysis base) at the bottom of the photoelectrolyzer-generator; a membrane from fire hose material, located between electrodes; device, regulating the gap between the electrodes. Round-the-clock and continuous production of hydrogen and oxygen in the photoelectrolyzer-generator is ensured by using lamp, including LED with a daylight battery charger as a useful electrical load, which brightens the combined anode, made from silicon semiconductor and metal mesh with large cells at night until the morning and by continuously filling the photoelectrolyzer-generator with water.

Structural and Dynamical Basis of VP35-RBD Inhibition by Marine Fungi Compounds to Combat Marburg Virus Infection.

The Marburg virus (MBV), a deadly pathogen, poses a serious threat to world health due to the lack of effective treatments, calling for an immediate search for targeted and efficient treatments. In this study, we focused on compounds originating from marine fungi in order to identify possible inhibitory compounds against the Marburg virus (MBV) VP35-RNA binding domain (VP35-RBD) using a computational approach. We started with a virtual screening procedure using the Lipinski filter as a guide. Based on their docking scores, 42 potential candidates were found. Four of these compounds-CMNPD17596, CMNPD22144, CMNPD25994, and CMNPD17598-as well as myricetin, the control compound, were chosen for re-docking analysis. Re-docking revealed that these particular compounds had a higher affinity for MBV VP35-RBD in comparison to the control. Analyzing the chemical interactions revealed unique binding properties for every compound, identified by a range of Pi-cation interactions and hydrogen bond types. We were able to learn more about the dynamic behaviors and stability of the protein-ligand complexes through a 200-nanosecond molecular dynamics simulation, as demonstrated by the compounds' consistent RMSD and RMSF values. The multidimensional nature of the data was clarified by the application of principal component analysis, which suggested stable conformations in the complexes with little modification. Further insight into the energy profiles and stability states of these complexes was also obtained by an examination of the free energy landscape. Our findings underscore the effectiveness of computational strategies in identifying and analyzing potential inhibitors for MBV VP35-RBD, offering promising paths for further experimental investigations and possible therapeutic development against the MBV.

High performance hydrogen evolution energy conversion devices via p type polaron surface state modulation

The processing of solar to hydrogen energy conversion semiconductor devices strongly relies on the charge mobility and reactivity of hydrogen evolution reactions. Intrinsic defects induced polaron has been applied on the surface of Cu2O polyhedron nanoparticles to modulate the hydrogen cations reduction and hydrogen evolution reaction by high charge mobility and H atoms high selective of specific external terminated atoms. With the polaron surface state applied on truncated octahedron Cu2O nanoparticle photocathode, the water splitting efficiency achieved 2.12 % at 0.2 V working bias. The hydrogen generation rate is as high as 9.38 L/m2⋅h. Besides, under 1.23 V applied bias, at 1 atm pressure and room temperature, there are over 64 L hydrogen gases are generated in only one hour, and the hydrogen generation rate is as high as 65.39 L/m2⋅h. During this study, a defined p typed polaron surface state for raising charge mobility and hydrogen evolution in solar to hydrogen conversion system is illustrated, which provides the reliable application in related photon to electron conversion and high performance energy conversion devices.

Steady states and kinetic modelling of the acid-catalysed ethanolysis of glucose, cellulose, and corn cob to ethyl levulinate.

Ethyl levulinate is a promising advanced biofuel and platform chemical that can be derived from lignocellulosic biomass by ethanolysis processes. It can be blended with both diesel and gasoline and, thus, used in conventional engines and infrastructure. Previously, it has been shown that alkyl levulinate/alcohol/alkyl ether mixtures exhibit significantly enhanced fuel properties relative to any of the individual fuel components, particularly when blended with conventional hydrocarbon liquid fuels. Consequently, this study specifically quantifies the three primary components of the alcoholysis reaction mixture: ethyl levulinate, diethyl ether, and ethanol. The steady state and kinetic phase fractions of ethyl levulinate and diethyl ether produced from glucose, cellulose, and corn cob with 0.5-2 mass% sulphuric acid in ethanol are determined for 5, 10, and 20 mass% of feedstock at 150 °C. Knowledge of the steady state equilibrium mixture fraction is specifically targeted due to its importance in assessing commercial-scale production and in modelling analysis as: (i) it defines the maximum yield possible at a given condition, and (ii) it is equitable to the minimum free energy state. Maximum steady state yields (mass%) of ethyl levulinate of (46.6 ± 3.7), (50.2 ± 5.4), and (27.0 ± 1.9)% are determined for glucose, cellulose, and corn cob, respectively. The conversion of glucose and cellulose to ethyl levulinate in the presence of ethanol and sulphuric acid is shown to be a catalytic process, where the ethyl levulinate yield is not dependent on the acid concentration. For corn-cob biomass, in a new and contrasting finding, the ethyl levulinate yield is shown to strongly depend on the acid concentration. This effect is also observed in the fractions of diethyl ether formed, providing strong evidence that the hydrogen cation is not being replenished in the ethanolysis process and the overall reaction with corncob is not wholly catalytic. Thus, for the acid catalysed alcoholysis of lignocellulosic biomass, acid concentration must be scaled with feedstock concentration. The critical corn cob-to-acid ratio that maximises ethyl levulinate yields while minimizing the formation of undesired co-products (diethyl ether) is in the range 10-20 : 1 at 150 °C. A detailed, hierarchical, mass-conserved chemical kinetic model capable of accurately predicting the relative abundance of the three primary components of the ethanolysis reaction: ethyl levulinate, diethyl ether, and ethanol, from the biochemical composition of the feedstock, is elucidated and validated.

An endo-functionalized molecular cage for selective potentiometric determination of creatinine.

Potentiometric ion-selective electrodes (ISEs), which rely on selective and lipophilic ionophores, are commonly employed in clinical diagnostics. However, there are very limited specific ionophores for the detection of creatinine, a critical biomarker for renal function assessment. In the present research, we designed and synthesized an endo-functionalized cage, which is able to selectively bind the creatininium cation (K a = 8.6 × 105 M-1) through the formation of multiple C-H⋯O and N-H⋯N hydrogen bonds and cation⋯π interactions. ISEs prepared with this host show a Nernstian response to creatinine and exhibit excellent selectivity and a low detection limit of 0.95 μM. In addition, the creatinine levels in urine or plasma samples determined by our sensor are consistent with those analyzed using enzymatic assay on a Cobas c702. The method is simple, fast and accurate, and amenable to clinical detection of creatinine levels.

Synthesis, characterization, and density functional theory investigation of (CH6N3)2[NpO2Cl3] and Rb[NpO2Cl2(H2O)] chain structures.

The actinyl tetrachloro complex [An(V/VI)O2Cl4]2-/3- tends to form discrete molecular units in both solution and solid state materials, but related aquachloro complexes have been observed as both discrete coordination compounds and 1-D chain topologies. Subtle differences in the inner sphere coordination significantly influence the formation of structural topologies in the actinyl chloride system, but the exact reasoning for these variations has not been delineated. In the current study, we present the synthesis, structural characterization, and vibrational analysis of two 1-D neptunyl(V) chain compounds: (CH6N3)2[NpO2Cl3] (Np-Gua) and Rb[NpO2Cl2(H2O)] (Np-Rb). Bonding and non-covalent interactions (NCIs) in the systems were evaluated using periodic Density Functional Theory (DFT) to link these properties to related phases. We observed ∼6.5% and ∼3.9% weakening of NpO bonds in Np-Gua and Np-Rb compared to the reference Cs3[NpO2Cl4]. NCI analysis distinguished specific assembly modes, where Np-Gua was connected via hydrogen bonding (N-H⋯Cleq and N-H⋯Oyl) and Np-Rb contained both cation interactions (Rb+⋯Oyl and Rb+⋯Cleq) and hydrogen bonding (Oeq-H⋯Oyl) networks. Thermodynamically viable formation pathways for both compounds were explored using DFT methodology. The [NpO2Cl4](aq)3- and [NpO2Cl3(H2O)](aq)2- substructures were identified as precursors to Np-Gua and [NpO2Cl3(H2O)](aq)2- and [NpO2Cl2(H2O)2](aq)- were isolated as the primary building units of Np-Rb. Finally, we utilized DFT to analyze the vibrational modes for Np-Gua and Np-Rb, where we found evidence of the NpO bond weakening within the Np(V) chain structures compared to [NpO2Cl4]3-.

Simultaneous generation of hydroxyl and hydrogen radicals from H+/OH- pairs caused by water-solid contact electrification.

Water-solid contact electrification is a common physical phenomenon involving interfacial electron and ion transfer, recently discovered to trigger unique redox reactions. Here, we demonstrate the generation of both hydroxyl and hydrogen radicals when water contacts SiO2. The coexistence of hydroxyl and hydrogen radicals is confirmed by simultaneous nitrate reduction and nitrite oxidation during the contact. Increased density of hydroxyl groups on the SiO2 surface enhances its surface electronegativity before the contact, as well as boosting charge transfer and radical generation during the contact. We propose that the simultaneous generation of hydroxyl and hydrogen radicals originates from electron gain and loss between hydroxide anions in water and hydrogen cations adsorbed on the solid surface, which are ion pairs separated by the interfacial electric field. This discovery advances our understanding of redox processes induced by contact electrification.

(Invited) Engineering Local Chemical Environments in Electrolytes and at Electrode-Electrolyte Interface for Efficient Aqueous Batteries

Electrolytes are an essential component of energy storage devices. Electrolyte composition has a significant impact on the environmental footprint, safety, price and performance of a battery. Aqueous electrolytes are non-flammable and can offer safer battery operation and lower toxicity. However, they suffer from a smaller electrochemical stability window compared to traditional organic electrolytes, which leads to lower energy density. To circumvent the small electrochemical stability window, highly concentrated “water-in-salt” (WIS) electrolytes, which demonstrate significantly wider stability window, were proposed and successfully applied to various aqueous energy storage systems including Li-ion and Zn metal batteries that are highly attractive for grid energy storage. However, since WIS electrolytes require large amounts of salt (often toxic) and have dramatically increased viscosity, it in turn limits their transport properties, charge-discharge rates, and usability in batteries.In this talk, the use of highly concentrated "water-in-salt" (WIS) electrolytes as a means of achieving increased charging efficiency and a wider stability window will be discussed in the context of aqueous Li-ion and Zn metal batteries. Further, we elaborate the role of cation solvation environment, electrolyte structure and hydrogen bonding on the physicochemical properties and electrochemical response of the system. We show that electrolyte composition affects the interfacial kinetics of Zn plating/stripping as well as the kinetics of the parasitic processes of electrolyte decomposition. Finally, we discuss how relatively dilute electrolytes can be engineered for efficient aqueous batteries. References Suo, O. Borodin, T. Gao, M. Olguin, J. Ho, X. Fan, C. Luo, C. Wang and K. Xu, Science, 2015, 350, 938Yamada, K. Usui, K. Sodeyama, S. Ko, Y. Tateyama and A. Yamada, Nat. Energy, 2016, 1, 16129R. Lukatskaya, J.I. Feldblyum, D.G. Mackanic, F. Lissel, D.L. Michels, Y. Cui, Z. Bao, Energy Environ. Sci., 2018, 11, 2876-2883 D.G. Vazquez, T. P. Pollard, J. Mars, J.M. Yoo, H.G. Steinrück, S. E. Bone, O. V. Safonova, M. F. Toney, O. Borodin, M.R. Lukatskaya, Energy Environ. Sci., 2023, DOI: 10.1039/D3EE00205E

Cationic Surfactant-Modified Tetraselmis sp. for the Removal of Organic Dyes from Aqueous Solution

The modification of the Tetraselmis sp. algae material (Tetra-Alg) with surfactant Cethyltrimethylammonium Bromide (CTAB) yielded adsorbent Tetra-Alg-CTAB as an adsorbent of methyl orange (MO) and methylene blue (MB) solutions. The characterization of the adsorbent used an infrared (IR) spectrometer to identify functional groups and Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX FEI Inspect-S50, Midland, ON, Canada) to determine the surface morphology and elemental composition. Methyl orange and methylene blue adsorption on the adsorbent Tetra-Alg, Tetraselmis sp. algae-modified Na+ ions (Tetra-Alg-Na), and Tetra-Alg-CTAB were studied, including variations in pH, contact time, concentration, and reuse of adsorbents. The adsorption of MO and MB by Tetra-Alg-CTAB at pH 10, during a contact time of 90 min, and at a concentration of 250 mg L−1 resulted in MO and MB being absorbed in the amounts of 128.369 and 51.013 mg g−1, respectively. The adsorption kinetics and adsorption isotherms of MO and MB and Tetra-Alg, Tetra-Alg-Na, and Tetra-Alg-CTAB tend to follow pseudo-second-order kinetics models and Freundlich adsorption isotherms with each correlation coefficient value (R2) approaching 1. Due to the modification with the cationic surfactant CTAB, anionic dyes can be strongly sorbed in alkaline pH due to strong electrostatic attraction, while MB is more likely to involve cation exchange and hydrogen bonding. The reuse of Tetra-Alg-CTAB was carried out four times with adsorption percent > 70%, and the adsorbent was very effective in the adsorption of anionic dyes such as MO.

Mechanism-based structure-activity relationship investigation on hydrolysis kinetics of atmospheric organic nitrates

Organic nitrates are key components of atmospheric organic aerosols. Hydrolysis is one of their main transformation pathways, affecting atmospheric nitrogen cycle and the properties of organic aerosols. Studying hydrolysis using experiments is hindered by limited authentic chemical standards. To advance our understanding on the hydrolysis of organic nitrates, we apply quantum chemistry methods here to establish a structure-activity relationship of the mechanisms and kinetics by selecting eight organic nitrates as model compounds. The results indicate that an acid-catalyzed mechanism is dominant for the most considered organic nitrates at pH corresponding to ambient organic aerosol (pH < 5). More importantly, a hydrolysis pathway driven by the shift of hydrogen or methyl cation is unveiled. Based on the revealed mechanisms, quaternary C at the α-site, tertiary/quaternary C at the β-site, and –C=C at the β/γ-site of the −ONO2 group are determined to be the key structural factors for the fast hydrolysis kinetics. An important feature for the hydrolysis of organic nitrates with such structural factors is proceeding via a carbocation intermediate. The formed carbocation could further mediate the organic aerosol chemistry, affecting the composition and properties of organic aerosols. This study provides a basis to further develop predictive models for hydrolysis kinetics of organic nitrates.