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Developing facile methods to modulate the structure and performance of photocatalysts plays a pivotal role in the potential large-scale application of photocatalytic hydrogen production. Herein, a series of uniformly sized and highly dispersed copper-doped cadmium sulfide (CdS) nanoparticles (NPs) were successfully synthesized through a facile cation exchange strategy. The resulting Cu-doped CdS samples exhibited a remarkable photocatalytic hydrogen production rate of 2459.3 μ mol·h−1g−1, nearly 11 times that of pure CdS. The introduction of Cu+ ions effectively reduced the band gap, leading to enhanced light absorption, as well as improved charge carrier separation and transfer efficiency. Meanwhile, the theoretical investigation further confirmed that Cu+ doping substantially decreased the free energy of hydrogen adsorption and provided more suitable active sites, thereby promoting the photocatalytic hydrogen production activity on CdS NPs. This work provides compelling evidence for the exploration of novel transition metal-doped photocatalysts for hydrogen production using the cation exchange method. [Display omitted] • Controllable Cu-doped CdS was prepared via cation-exchange approach. • Cu doping induced extended light absorption and accelerated charge separation. • HER was promoted by reduced free energy of hydrogen adsorption via Cu doping. • Photocatalytic hydrogen production of CdS was enhanced by 11 times. [ABSTRACT FROM AUTHOR]

Therapeutic antibodies play an important role in the public healthcare system to treat patients with a variety of diseases. Protein characterization using an array of analytical tools provides in-depth information for drug quality, safety, efficacy, and the further understanding of the molecule. A therapeutic antibody candidate MAB1 exhibits unique binding properties to both cation and anion exchange columns at neutral pH. This uniqueness disrupts standard purification processes and necessitates adjustments in manufacturing. This study identifies that the charge heterogeneity of MAB1 is primarily due to the N-terminal cyclization of glutamine to pyroglutamine and, to a lesser extent, succinimide intermediate, deamidation, and C-terminal lysine. Using three approaches, i.e., deferential chemical labeling, H/D exchange, and molecular modeling, the binding to anion exchange resins is attributed to negatively charged patches on the antibody's surface, involving specific carboxylic acid residues. The methodologies shown here can be extended to study protein binding orientation in column chromatography. [ABSTRACT FROM AUTHOR]

Phase control over cation exchange (CE) reactions has emerged as an important approach for the synthesis of nanomaterials (NMs), enabling precise determination of their reactivity and properties. Although factors such as crystal structure and morphology have been studied for the phase engineering of CE reactions in NMs, there remains a lack of systematic investigation to reveal the impact for the factors in heterogeneous materials. Herein, we report a molybdenum disulfide induced phase control method for synthesizing multidimensional Co3S4‐MoS2 heteronanostructures (HNs) via cation exchange. MoS2 in parent Cu1.94S‐MoS2 HNs are proved to affect the thermodynamics and kinetics of CE reactions, and facilitate the formation of Co3S4‐MoS2 HNs with controlled phase. This MoS2 induced phase control method can be extended to other parent HNs with multiple dimensions, which shows its diversity. Further, theoretical calculations demonstrate that Co3S4 (111)/MoS2 (001) exhibits a higher adhesion work, providing further evidence that MoS2 enables phase control in the HNs CE reactions, inducing the generation of novel Co3S4‐MoS2 HNs. As a proof‐of‐concept application for crystal phase‐ and dimensionality‐dependent of cobalt sulfide based HNs, the obtained Co3S4‐MoS2 heteronanoplates (HNPls) show remarkable performance in hydrogen evolution reactions (HER) under alkaline media. This synthetic methodology provides a unique design strategy to control the crystal structure and fills the gap in the study of heterogeneous materials on CE reaction over phase engineering that are otherwise inaccessible. [ABSTRACT FROM AUTHOR]

Metal chalcogenide nanocrystals with variable composition and shape can conveniently be produced using cation exchange synthesis; however, the presence of cation‐containing ligands inherited from the starting material often results in contamination of the final product. To address this issue, a two‐step ligand replacement strategy is developed to fabricate CuInSe2/CuInS2 nanorods from CdSe/CdS nanorods via removal of Cd‐phosphonates from an intermediate Cu2‐xSe/Cu2‐xS phase used in the cation exchange conversion. This synthetic approach furnishes CuInSe2/CuInS2 nanorods with cadmium content below 1 at.%, and high photoluminescence quantum yields reaching 40% in the near‐infrared spectral range. Transient absorption studies reveal that the band alignment in the CuInSe2/CuInS2 heterostructure features a quasi‐type II character, with an electron localized in the core and a hole wavefunction spread over the entire nanorod. The efficient passivation of the core and the reduced Cd content leads to excitonic emission with full width at half maximum down to 110 meV, superimposed with a broad emission band from copper‐induced defects. Field‐effect transistors based on cadmium‐free CuInSe2/CuInS2 nanorods show two orders of magnitude lower noise current density compared with the cadmium‐rich devices. The responsivity and specific detectivity of these devices reach 230 mA W−1 and 108 Jones, respectively, under near‐infrared excitation at room temperature. [ABSTRACT FROM AUTHOR]

The synthesis of the accurate composition and morphological/structural design of multielement semiconductor materials is considered an effective strategy for obtaining high-performance hybrid photocatalysts. Herein, sulfur vacancy (Vs)-bearing In2S3/CuInS2 microflower heterojunctions (denoted Vs-In2S3/CuInS2) were formed in situ using In2S3 microsphere template-directed synthesis and a metal ion exchange-mediated growth strategy. Photocatalysts with flower-like microspheres can be obtained using hydrothermally synthesized In2S3 microspheres as a template, followed by Ostwald ripening growth during the metal cation exchange of Cu+ and In3+. The optimal heterostructured Vs-In2S3/CuInS2 microflowers exhibited CO and CH4 evolution rates of 80.3 and 11.8 μmol g−1 h−1, respectively, under visible-light irradiation; these values are approximately 4 and 6.8 times higher than those reported for pristine In2S3, respectively. The enhanced photocatalytic performance of the Vs-In2S3/CuInS2 catalysts could be attributed to the synergistic effects of the following factors: (i) the constructed heterojunctions accelerate charge-carrier separation; (ii) the flower-like microspheres exhibit highly uniform morphologies and compositions, which enhance electron transport and light harvesting; and (iii) the vs. may trap excited electrons and, thus, inhibit charge-carrier recombination. This study not only confirms the feasibility of the design of heterostructures on demand, but also presents a simple and efficient strategy to engineer metal sulfide photocatalysts with enhanced photocatalytic performance. [ABSTRACT FROM AUTHOR]

Lepidocrocite-type layered sodium titanate (NaxH2−xTi2O5) is widely used in environmental remediation because of its large specific surface area, formed by anisotropic crystal growth, and its ability to store and exchange cations between layers. Additionally, peroxo-titanate nanotubes (PTNTs), which are tubular titanates with peroxy groups, exhibit visible-light absorption capabilities, rendering them suitable for photocatalytic applications under visible light irradiation. However, because of cation exchange reactions, the Na+ concentration and pH of the solution can fluctuate under aqueous conditions, affecting the photocatalytic performance of the PTNTs. Herein, we evaluated the impact of cation exchange reactions on the photocatalytic degradation of Rhodamine B (Rh B) by PTNTs at controlled Na+ ratios. The observed pH of Rh B solutions increases due to the cation exchange reaction with Na+ and H3O+, leading to the formation of zwitter-ionic Rh B molecules, eventually weakening their adsorption and photodegradation performance. Moreover, the results indicate that inhibiting the pH increase of the Rh B solution can prevent the weakening of both the adsorption and photodegradation performance of PTNTs. This study highlights the significance of regulating the sodium ion content in layered titanate materials, emphasizing their importance in optimizing these materials' photocatalytic efficacy for environmental purification applications. [ABSTRACT FROM AUTHOR]

The concentration of heavy metals in soil layers has increased due to the rapid development of the industry. Lead and zinc are two frequent heavy metal contaminants in soil. This paper aims to study the effect of these types of contaminants on different fines, including kaolinite, bentonite, and zeolite mixed with sand. First, mixtures of sand and kaolinite, bentonite, and zeolite were prepared, then they were contaminated by two contaminants of lead and zinc nitrates, separately. Consolidated undrained triaxial tests, Soil Conservation Service (SCS) double hydrometer tests, scanning electron microscope (SEM), Atterberg limits, and pH determination tests were conducted on the soil samples to investigate the changes in the strength and microstructure in the presence of heavy metals. In general, triaxial test results showed that various parameters influence the strength results of these heavy metal-contaminated sandy soil samples such as type, percentage, and structure of the fine portion, type, and concentration of contaminants, bonding mechanism of fine grains, and ion exchange capacity. For instance, in the presence of kaolinite (and kaolinite-zeolite mixtures), contamination with lead decreased the strength of soil samples, but in the soil mixtures containing bentonite (and bentonite-kaolinite mixtures), an opposite trend was seen. The plasticity index of mixtures containing kaolinite and zeolite increased in the presence of heavy metal contaminants, but it decreased when the fine portion of the soil was bentonite. Heavy metal contaminants decreased the pH of all soil mixtures and made them to be acidic. The results of the SCS double hydrometer test and SEM indicated that contaminated kaolinite and zeolite soil mixtures have a dispersed structure, while bentonite soil mixtures are not dispersive. [ABSTRACT FROM AUTHOR]

A geosynthetic clay liner (GCL) was exhumed from a composite liner (geomembrane over GCL containing granular sodium bentonite) in the base of a landfill cell after 12 years of atmospheric exposure. The GCL was altered appreciably during exposure, despite being overlain by a geomembrane. Water content, hydration, and bentonite erosion varied considerably along the slope. GCL samples from the top of the slope were dry, with visible bentonite granules comparable to those in a virgin GCL as if the bentonite had not hydrated. No substantial change in exchange complex or swell index (SI) occurred in samples from the top of the slope, and hydraulic conductivity of these samples to water was low (≈10−11 m/s). GCL samples from the toe of the slope varied considerably, from moist and soft to dry and cracked, but all had undergone hydration, and had low SI, a small mole fraction of monovalent cations in the exchange complex, and high hydraulic conductivity (10−8 m/s or higher). Bentonite in GCL samples from midslope had a cracked structure commonly observed in GCLs that have undergone wet–dry cycling. Midslope GCLs typically had hydraulic conductivity greater than 10−7 m/s. A sample from the top of the slope from a location near a GCL panel separation was comparable to other samples from the top of the slope. GCL samples from the anchor trench differed considerably, being very permeable or having low hydraulic conductivity. Hydraulic conductivity was strongly correlated with SI; GCL samples with SI<15 mL/2 g were highly permeable, and those with SI>15 mL/2 g were comparable to a virgin GCL. The variation in SI was related directly to replacement of sodium by calcium in the exchange complex of the bentonite. Hydraulic conductivity also was affected by the thinning of the GCL. [ABSTRACT FROM AUTHOR]

Salt stress seriously hinders the normal growth of plant seedling roots. Magnesium, as one of the essential medium elements for plant growth, can effectively alleviate the damage of salt stress to plant roots, but the key genes involved and their mechanism are still unclear. The purpose of this study was to explore the related molecular mechanism of exogenous magnesium regulating cation homeostasis in peanut seedlings under salt stress. Firstly, according to plant physiology experiments, it was found that exogenous magnesium treatment significantly improved the tolerance of peanut seedlings to salt stress. After that, the transcriptome data were integrated, and further gene expression analysis showed that the expression of genes such as CNGC1, NCLs, and NHX7 was regulated under exogenous magnesium treatment, which effectively reduced the accumulation of sodium ions in cells. At the same time, exogenous magnesium also regulates the expression of genes such as ACAs and POTs and maintains the homeostasis of calcium and potassium ions in cells. These results reveal the molecular mechanism of exogenous magnesium regulating the cation homeostasis of peanut seedlings under salt stress, which provides an important reference for further revealing the key genes of salt tolerance in plants. [ABSTRACT FROM AUTHOR]

Interactions at the oil/brine/rock interfaces play a pivotal role in the mobility of crude oil within reservoir matrices. Unraveling the microscopic mechanisms of these interactions is crucial for ion-engineered water flooding in secondary and tertiary oil recovery. In this study, the occurrence and transport behavior of crude oil in kaolinite nanopores covered with thin brine films was investigated by molecular dynamics simulation. There is an apparent interface layered phenomenon for the liquid molecules in slit pores and the polar oil components primarily concentrate at the oil/brine interfacial region and form various binding connections with ions. The interfacial interactions between the polar oil components and brine ions exhibit an inhibitory effect on the transport of crude oil through nanopores. The interaction mechanism between acetic acid molecules and hydrated ions was elucidated by interaction modes and interaction intensity, which was proved to illustrate the flow difference in different brine film systems. Moreover, a strategy of exchanging the binding sites of divalent cations with acetic acid molecules by monovalent cations with a higher concentration was proposed. The cation exchange scheme was further validated, demonstrating an enhancement in the oil mobility within nanopores. These findings deepen our understanding of oil/brine/rock interfacial interactions and provide a significant molecular perspective on ion-engineered water flooding for enhanced oil recovery. [ABSTRACT FROM AUTHOR]

Montmorillonite (Mt) is a ubiquitous swelling clay mineral and major component of soft rocks, sediments, and soils with an inherent capability to sorb metal cations. This unique feature renders Mt important for the enrichment and mobilization of environmentally important metal cations, retardation of heavy metals and radionuclide ions, the evolution of clay mineral itself, soils and sediments, and other geological processes. Understanding the interfacial interactions of Mt with metal cations at the molecular level is of fundamental importance in all these processes, but still remains elusive, due to the chemical and structural complexity of Mt surfaces and the diverse chemistries of metal cations. In this Review, we aim to provide the reader with a comprehensive overview of the adsorption modes of metal cations on basal and edge surfaces of Mt, local chemical environments of the cation binding sites, the driving forces for metal sorption, and factors influencing the dynamics of cation uptake onto Mt surfaces. Various surface complexation models [i.e., nonelectrostatic model (NEM), constant capacitance model (CCM), diffuse layer model (DLM), and triple-layer model (TLM)], advanced spectroscopic techniques (i.e., NEM, CCM, DLM, and TLM), and atomistic simulation methods (i.e., MD, DFT, and FPMD) have been used in conjunction with macroscopic adsorption experiments to gain detailed insights into the interfacial interactions of metal cations on Mt. Mt adsorbs metal cations via three independent pathways: (1) cation exchange; (2) surface complexation; and (3) nucleation and surface precipitation. The principal driving force for cation exchange is electrostatic interaction, while chemical bonding governs the two other mechanisms that depend on the basal and edge surface properties of Mt. The siloxane cavities on the tetrahedral basal plane exhibit the strongest adsorption sites for cation exchange and are greatly affected by the the degree of Al3+/Si4+ tetrahedral substitutions. At the amphoteric edge surfaces bearing hydroxyl groups, metal cations could form mono/multidentate surface complexes on Mt [010] and [110] edges. Ionic strength, pH, the presence of competing cations, temperature, and layer charge have been shown to affect the adsorption mechanisms and quantity of adsorbed cations. The updated information on the interfacial interactions of metal cations with Mt basal and edge surfaces presented in this review provides an improved understanding of the enrichment of metals, formation of metal ores, and natural biogeochemical cycles, as well as may promote technological and engineering applications of this important clay mineral in environmental remediation, geological repository, petroleum exploration and extraction, and extraterrestrial research. [ABSTRACT FROM AUTHOR]

To trace Critical Zone processes and to quantify Li fluxes from one Critical Zone compartment into another, we investigated the Li concentration and isotopic composition (δ7Li) of time-series water samples (including subsurface flow, groundwater and creek water), vegetation, bedrock (including separated minerals from bedrock), and regolith (including exchangeable fraction and clay-sized fraction of regolith) in a temperate forested headwater catchment in the Black Forest, Conventwald, Germany. Our estimation of the Li budget shows that atmospheric deposition and biological processes played minor roles in the Li cycle relative to chemical weathering. All water samples (δ 7Li value of 6.5 to 20.4 ‰) were enriched in 7Li compared to bedrock (-1.3 ‰) and regolith (∼-1.7 ‰), but δ7Li differed between water pathways: δ7Li variations in subsurface flow, creek water and groundwater were controlled by conservative mixing, exchangeable pool buffering and Li incorporation/adsorption, respectively. Fractionated heavy Li isotopes in water samples resulted from the formation of secondary solids which preferentially incorporated 6Li, with the separated clay-sized fraction of the regolith exhibiting more negative δ7Li values (-5.4 to −3.5 ‰) than the bulk regolith (∼-1.7 ‰). However, Li in secondary solids only accounted for 8 ± 6 % of the total Li hosted in bulk regolith, and consequently δ7Li in soil did not differ significantly from δ 7Li in bedrock. This is unexpected considering water is continuously removing 7Li in preference over 6Li from regolith. Mass balance calculations applied at the catchment scale point to an irreconcilable imbalance with our data. On one hand, the regolith's δ7Li values are not negative enough to balance the 7Li export by river water, and on the other hand Li in the riverine dissolved load only accounts for ∼ 30 % of the Li solubilized from regolith. Therefore, we suggest that there might be a "hidden export pathway" for Li at our site, possibly subsurface removal of fine particles enriched in 6Li. In light of increasingly frequent observations of such isotopic imbalances in the Critical Zone this phenomenon deserves increased attention. [ABSTRACT FROM AUTHOR]

Owing to the absence of organic cations, all‐inorganic perovskite exhibits superior thermal and irradiation stability compared to organic‐inorganic perovskite. However, it is difficult for the traditional solution method to produce pinhole‐free and phase‐pure all‐inorganic perovskite films, which hinders its application. Here, a method of in situ A‐site cation exchange to synthesize CsPbBr3 films is introduced. The MAPbBr3 films are treated with CsAc solution to initiate cation exchange, where the intermediate product MAAc plays a crucial role in guiding grain growth during evaporation, resulting in the production of pinhole‐free and phase‐pure CsPbBr3 films. The self‐powered photodetector, based on compact and pinhole‐free CsPbBr3 film, exhibits excellent performance with an LDR of 126.7 dB, a detectivity of 1.1 × 1013 Jones, and a rise/decay time of 2.9/25.1 µs. Furthermore, the photodetector maintains over 90% of its original performance after a 2500 s irradiation test and a 30‐day air exposure test. Benefiting from the exceptional device performance and stability, the photodetector proves to be a valuable component in the laser eavesdropping system. [ABSTRACT FROM AUTHOR]

Thick‐shell colloidal quantum dots (QDs) are promising building blocks for solar technologies due to their size/composition/shape‐tunable properties. However, most well‐performed thick‐shell QDs suffer from frequent use of toxic metal elements including Pb and Cd, and inadequate light absorption in the visible and near‐infrared (NIR) region due to the wide bandgap of the shell. In this work, eco‐friendly AgInSe2/AgInS2 core/shell QDs, which are optically active in the NIR region and are suitable candidates to fabricate devices for solar energy conversion, are developed. Direct synthesis suffers from simultaneously controlling the reactivity of multiple precursors, instead, a template‐assisted cation exchange method is used. By modulating the monolayer growth of template QDs, gradient AgInSeS shell layers are incorporated into AgInSe2/AgInS2 QDs. The resulting AgInSe2/AgInSeS/AgInS2 exhibits better charge transfer than AgInSe2/AgInS2 due to their favorable electronic band alignment, as predicted by first‐principle calculations and confirmed by transient fluorescence spectroscopy. The photoelectrochemical cells fabricated with AgInSe2/AgInSeS/AgInS2 QDs present ≈1.5‐fold higher current density and better stability compared to AgInSe2/AgInS2. The findings define a promising approach toward multinary QDs and pave the way for engineering the QDs' electronic band structures for solar‐energy conversion. [ABSTRACT FROM AUTHOR]

Carbonate weathering plays a significant role in regulating global carbon budget at short time scales, and thus needs to be better constrained in the context of global warming. Riverine magnesium isotopes (δ26Mg) have the potential to trace carbonate weathering intensity (CWI) but require further testing under various climatic and geological settings. Cation exchange is an important mechanism buffering river water chemistry, especially in catchments characterized by high erosion. However, field evidence on the influence of cation exchange on riverine δ26Mg is rare. In this study, spatial riverine δ26Mg variation within the Three Rivers (i.e., the Jinsha Jiang, the Lancang Jiang, and the Nu Jiang), three extremely-high-erosion catchments in the southeastern Tibetan Plateau, was investigated to address this issue. The results showed that riverine δ26Mg values present a wide range from –1.11 ‰ to –0.59 ‰ in the Jinsha Jiang, from –1.39 ‰ to –0.65 ‰ in the Lancang Jiang, and from –1.19 ‰ to –0.50 ‰ in the Nu Jiang. An inversion model was used to partition riverine Mg2+ sources and confirmed that the riverine Mg2+ budget was dominated by carbonate weathering, followed by evaporite dissolution. However, conservative mixing could not explain riverine δ26Mg variation within the Three Rivers catchments, because measured δ26Mg values (δ26Mg measured) systematically deviated from the modeled ones (δ26Mg modeled), with Δ26Mg measured–modeled (δ26Mg measured – δ26Mg modeled) up to 0.79 ‰. The positive correlations between Δ26Mg measured–modeled and suspended particulate matter (SPM) concentrations indicate Mg isotopic fractionation was related to high suspended loads owing to extremely-high erosion rates. Given the significant cation exchange capacity of SPM, Mg2+-Na+ exchange is proposed for the first time as an explanation for the observed δ26Mg variations in the rivers draining the Tibetan Plateau, although the role of carbonate precipitation could not be excluded. The strong positive correlations between riverine δ26Mg and exchangeable Mg/Na ratios in the Three Rivers further support that light Mg isotopes may be preferentially retained in the riverine exchange pool during Mg2+-Na+ exchange, driving riverine δ26Mg towards higher values. Expanding our finding to global rivers, the negative correlation between riverine δ26Mg and CWI can be interpreted by a competition between the fast dissolution of carbonates leading to the enrichment of 24Mg in waters and Mg isotope fractionation induced by cation exchange leading to the depletion of 24Mg in the residual waters. This study provides new insight into cation exchange as a regulator of riverine δ26Mg and Mg cycling, highlighting the robustness of riverine δ26Mg in tracing CWI and constraining the carbon cycle. [ABSTRACT FROM AUTHOR]

Lead chalcogenide nanoplatelets (NPLs) have emerged as a promising material for devices operating in the near IR and IR spectrum region. Here, we first apply the cation exchange method to PbSe/PbS core/shell NPL synthesis. The shell growth enhances NPL colloidal and environmental stability, and passivates surface trap states, preserving the main core physical properties. To prove the great potential for optoelectrical applications, we fabricate a photoconductor using PbSe/PbS NPLs. The device demonstrates enhanced conductivity and responsivity with fast rise and fall times, resulting in a 13 kHz bandwidth. The carrier transport was investigated with the field effect transistor method, showing p-type conductivity with charge mobility of 1.26 × 10−2 cm2·V−1·s−1. [ABSTRACT FROM AUTHOR]

In order to reduce the degree of efflorescence in alkali-activated metakaolin geopolymers, a modified 5A zeolite with cation-exchange properties was used to reduce the content of free alkali metal cations in the geopolymer. This work aims to investigate the effect of different dosages of modified 5A zeolite on the microstructure and properties of geopolymer by using compressive strength testing, pore structure analysis (BET), and SEM-EDS. The cation content in the leachate was evaluated using inductively coupled plasma atomic emission spectrometry (ICP-OES). The efflorescence area of the geopolymer was calculated using Image Pro Plus (IPP) software to evaluate the effect of modified 5A zeolite on the degree of efflorescence of the geopolymer and to reveal the effect of modified 5A zeolite on the migration patterns of Na+ and Ca2+ in the geopolymer. The results showed that modified 5A zeolite with a 4 wt.% content could optimize the pore structure and enhance the mechanical properties of MK geopolymer through internal curing and micro-aggregate effects, which could also exchange cations with the pore solution to form (N, C)-A-S-H gels. The Na+ leaching was reduced by 19.4%, and the efflorescence area of the MK geopolymer was reduced by 57.3%. [ABSTRACT FROM AUTHOR]

[Display omitted] Construction of semiconductor heterojunctions which promote the separation and transport of photogenerated carriers is an effective strategy for improving photocatalytic reaction efficiency. Based on the anisotropic electrical conductivity of layered ZnIn 2 S 4 (ZIS) photocatalyst, an efficient heterojunction should be constructed along the layer plane of ZIS, that is, a J type heterojunction. However, achieving controllable synthesis of the oriented heterojunction of ZIS faces challenges. Herein, we develop a facile, cost-effective and spatially-selective cation exchange synthesis approach to construct J type ZnIn 2 S 4 @CdIn 2 S 4 (J-ZIS@CIS) heterojunction using a flower-like hexagonal ZIS as the parent material. The developed synthesis approach can also control crystal structure of the heterojunction component CIS. This work presents a facile and controllable synthesis strategy to construct oriented anisotropic heterojunctions that are otherwise inaccessible. The as-prepared J-ZIS@CIS heterojunction displays a greatly enhanced photocatalytic hydrogen evolution activity with a rate of 183 μmol h−1, 2.77 times higher than that of pristine ZIS. Furthermore, the possible photocatalytic reaction mechanism is presented for the heterojunction. [ABSTRACT FROM AUTHOR]

The inferior electrical conductivity of conventional electrodes and their slow charge transport impose limitations on the electrochemical performance of supercapacitors (SCs) using those electrodes, necessitating strategies to overcome the limitations. An in situ Ag ion‐incorporated cation‐exchanged bimetallic sulfide/metal oxide heterostructure (Ag‐Co9‐xFexS8@α‐FexOy) is synthesized using a two‐step hydrothermal method. The coordination bond formation and Ag nanoparticle (NP) incorporation improve the electrical conductivity and adhesion of the heterostructure and reduce its interface resistance and volume expansion throughout the charge/discharge cycles. Density functional theory investigations indicate that the remarkable interlayer and interparticle conductivities of the heterostructure resulting from Ag doping have changed its electronic states, leading to an enhanced electrical conductivity. The optimized electrode has an excellent specific capacity (213.6 mA h g−1 at 1 A g−1) and can maintain 93.2% capacity retention with excellent Coulombic efficiency over 20 000 charge/discharge cycles. A flexible solid‐state extrinsic pseudocapacitor (EPSC) is fabricated using Ag‐Co9‐xFexS8@α‐FexOy and Ti3C2TX electrodes. The EPSC has specific and volumetric capacitances of 259 F g−1 and 2.7 F cm−3 at 0.7 A g−1, respectively, an energy density of 80.9 Wh kg−1 at 525 W kg−1, and a capacity retention of 92.8% over 5000 charge/discharge cycles. [ABSTRACT FROM AUTHOR]

With the aim of better directing the polycondensation of oligomers during the synthesis of amorphous aluminosilicate xerogels by the sol-gel process using Na2SiO3, we reinforced the sols with K+ counterion and studied its effect on the physicochemical and structural properties of the xerogels using XRD, FTIR, N2 physisorption, SEM, EDX, and TGA techniques as well as quantitative analysis of the acid sites by N-butylamine adsorption followed by potentiometric titration. Based on the results, the introduction of K+ generated xerogels with good porosity and conferred resistance to matrix cracking. The amorphous character of the xerogels did not change after adding K+. FTIR spectra showed that the composition of the xerogels was improved after the addition of K+. Cation exchange and sulfur removal were much more efficient in the presence of K+ which improved the acidity of the xerogels. The best percentages of Si and Al were observed at the Na+/K+ ratios of 4 and 1.The enhanced xerogel prepared with Na+/K+ ratio of 1 gave a biodiesel yield of 80.44% at the optimum parameters and was used for three reaction cycles without significant loss of biodiesel yield. [ABSTRACT FROM AUTHOR]

Chemical weathering is one of the most important processes on the Earth's surface, and lithium isotopes have been used as a promising tracer of silicate weathering, as the secondary clay minerals precipitated during silicate weathering are thought to preferentially incorporate the lighter 6Li isotope. However, to utilize lithium isotopes as a geochemical tracer, it is essential to quantitatively understand the partitioning of Li in clay minerals, including structurally bound Li and exchangeable interlayer ions, as well as the associated isotope fractionation. With classical molecular dynamic simulations and thermodynamic calculations, the cation exchange between Na-/K-montmorillonite and solvated Li in environmental solution are disclosed under different aqueous activity conditions. The Li+ ion, whose hydration ability is stronger than Na+ and K+ ions, is easier to swell the montmorillonite and shows less affinity for the clay. And the calculated cationic selectivity coefficients between Na+/K+ and Li+ ions are K c (Li → Na) = 2.0, K c (Li → K) = 10.0 for Arizona-type montmorillonite and K c (Li → Na) = 1.0, K c (Li → K) = 4.0 for Wyoming-type montmorillonite, which are comparable to reported experiments. The cationic partition of Li in the clay interlayer decreases when the hydration states of montmorillonite transform from triple-layer to bilayer and then to monolayer. Based on the density functional theory, the Li isotope fractionations for Li in clay interlayer sites and structural octahedral sites are further derived by thermodynamic calculations with path integral molecular dynamic simulation, which deals with the quantum anharmonicity. The behaviors of Li isotope in the bilayer hydration state closely resembles that in the aqueous solution, and only a slight Li isotope fractionation is found between the monolayer hydrated octahedral-substituted clay and solution phase (Δ7Li monolayer-aq = −2.0‰). While Li isotope fractionation between aqueous solution and mica structural sites is significant (Δ7Li structural-aq = −10.4‰) and shows an obvious quantum anharmonicity, which indicates the importance of the anharmonic treatment for Li isotope fractionation calculations. The newly calculated Li equilibrium isotope fractionation between clay and aqueous solution deviates from the experimentally determined fractionation factor, which can be attributed to the kinetic effects. Moreover, on the basis of the surface kinetic reaction model, the Li isotope fractionation becomes more pronounced with higher clay growth rate. By integrating the cationic selectivity coefficient and Li isotope fractionation, it is possible to constrain the fluid composition during Li-clay deposit and diagenesis, and to evaluate the intensity of chemical weathering processes as well as the related carbon cycle. [ABSTRACT FROM AUTHOR]

Cesium methylammonium lead iodide (CsxMA1−xPbI3) nanocrystals were obtained with a wide range of A‐site Cs‐MA compositions by post‐synthetic, room temperature cation exchange between CsPbI3 nanocrystals and MAPbI3 nanocrystals. The alloyed CsxMA1−xPbI3 nanocrystals retain their photoactive perovskite phase with incorporated Cs content, x, as high as 0.74 and the expected composition‐tunable photoluminescence (PL). Excess methylammonium oleate from the reaction mixture in the MAPbI3 nanocrystal dispersions was necessary to obtain fast Cs‐MA cation exchange. The phase transformation and degradation kinetics of films of CsxMA1−xPbI3 nanocrystals were measured and modeled using an Avrami expression. The transformation kinetics were significantly slower than those of the parent CsPbI3 and MAPbI3 nanocrystals, with Avrami rate constants, k, at least an order of magnitude smaller. These results affirm that A‐site cation alloying is a promising strategy for stabilizing iodide‐based perovskites. [ABSTRACT FROM AUTHOR]

Cesium methylammonium lead iodide (CsxMA1−xPbI3) nanocrystals were obtained with a wide range of A‐site Cs‐MA compositions by post‐synthetic, room temperature cation exchange between CsPbI3 nanocrystals and MAPbI3 nanocrystals. The alloyed CsxMA1−xPbI3 nanocrystals retain their photoactive perovskite phase with incorporated Cs content, x, as high as 0.74 and the expected composition‐tunable photoluminescence (PL). Excess methylammonium oleate from the reaction mixture in the MAPbI3 nanocrystal dispersions was necessary to obtain fast Cs‐MA cation exchange. The phase transformation and degradation kinetics of films of CsxMA1−xPbI3 nanocrystals were measured and modeled using an Avrami expression. The transformation kinetics were significantly slower than those of the parent CsPbI3 and MAPbI3 nanocrystals, with Avrami rate constants, k, at least an order of magnitude smaller. These results affirm that A‐site cation alloying is a promising strategy for stabilizing iodide‐based perovskites. [ABSTRACT FROM AUTHOR]

This work suggests an intriguing light‐driven atomic assembly proposal to orderly configure the distribution of reactive sites to optimize the spin‐entropy‐related orbital interaction and charge transfer from electrocatalysts to intermediates. Herein, the introduced fluorine (F) atoms acting as photo‐corrosion centres in MnO1.9F0.1 effectively soften the bonding interaction of Mn−O bonds in the IrCl3 solution. Therefore, partial Mn atoms can be successively replaced to form orderly atomic‐hybridized catalysts with a spin‐related low entropy due to the coexistence of Ir‐atomic chains and clusters. The time‐related elemental analysis demonstrates that the dynamic dissolution/redeposition of Ir clusters in acidic oxygen evolution leads to a reintegration of the reaction pathway to seek the switchable rate‐limiting step with a lower activation energy. [ABSTRACT FROM AUTHOR]

This work suggests an intriguing light‐driven atomic assembly proposal to orderly configure the distribution of reactive sites to optimize the spin‐entropy‐related orbital interaction and charge transfer from electrocatalysts to intermediates. Herein, the introduced fluorine (F) atoms acting as photo‐corrosion centres in MnO1.9F0.1 effectively soften the bonding interaction of Mn−O bonds in the IrCl3 solution. Therefore, partial Mn atoms can be successively replaced to form orderly atomic‐hybridized catalysts with a spin‐related low entropy due to the coexistence of Ir‐atomic chains and clusters. The time‐related elemental analysis demonstrates that the dynamic dissolution/redeposition of Ir clusters in acidic oxygen evolution leads to a reintegration of the reaction pathway to seek the switchable rate‐limiting step with a lower activation energy. [ABSTRACT FROM AUTHOR]

Oriented synthesis of transition metal sulfides (TMSs) with controlled compositions and crystal structures has long been promising for electronic devices and energy applications. Liquid‐phase cation exchange (LCE) is a well‐studied route by varying the compositions. However, achieving crystal structure selectivity is still a great challenge. Here, we demonstrate gas‐phase cation exchange (GCE), which can induce a specific topological transformation (TT), for the synthesis of versatile TMSs with identified cubic or hexagonal crystal structures. The parallel six‐sided subunit (PSS), a new descriptor, is defined to describe the substitution of cations and the transition of the anion sublattice. Under this principle, the band gap of targeted TMSs can be tailored. Using the photocatalytic hydrogen evolution as an example, the optimal hydrogen evolution rate of a zinc‐cadmium sulfide (ZCS4) is determined to be 11.59 mmol h−1 g−1, showing a 36.2‐fold improvement over CdS. [ABSTRACT FROM AUTHOR]

Oriented synthesis of transition metal sulfides (TMSs) with controlled compositions and crystal structures has long been promising for electronic devices and energy applications. Liquid‐phase cation exchange (LCE) is a well‐studied route by varying the compositions. However, achieving crystal structure selectivity is still a great challenge. Here, we demonstrate gas‐phase cation exchange (GCE), which can induce a specific topological transformation (TT), for the synthesis of versatile TMSs with identified cubic or hexagonal crystal structures. The parallel six‐sided subunit (PSS), a new descriptor, is defined to describe the substitution of cations and the transition of the anion sublattice. Under this principle, the band gap of targeted TMSs can be tailored. Using the photocatalytic hydrogen evolution as an example, the optimal hydrogen evolution rate of a zinc‐cadmium sulfide (ZCS4) is determined to be 11.59 mmol h−1 g−1, showing a 36.2‐fold improvement over CdS. [ABSTRACT FROM AUTHOR]

Solid‐state NMR has been applied to a series of Barluenga‐type iodine(I) [L‐I‐L]PF6 (L=pyridine, 4‐ethylpyridine, 4‐dimethylaminopyridine, isoquinoline) complexes as their hexafluorophosphate salts, as well as their respective non‐liquid ligands (L), their precursor silver(I) complexes, and the respective N‐methylated pyridinium and quinolinium hexafluorophoshate salts. These results are compared and contrasted to the corresponding solution studies and single‐crystal X‐ray structures. As the first study of its kind on the solid‐state NMR behavior of halogen(I) complexes, practical considerations are also discussed to encourage wider utilization of this technique in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ranitidine (RT) removal from water by natural Ca-montmorillonite (SAz-1) was studied. • Maximum RT adsorption value was 369.2 mg/g. • Cation exchange was the main mechanism for RT removal. • Molecular morphology of RT was crucial for its interaction with SAz-1. Adsorption behavior of ranitidine hydrochloride (RT) on a Ca-montmorillonite (SAz-1) was studied in aqueous system through batch experiments. The adsorption kinetics revealed that the equilibrium reached within 0.25 h and the data fitted well to the pseudo-second order kinetic equation (R2 = 0.98). The maximum RT adsorption capacity of SAz-1 was 369.2 mg/g and the adsorption isotherm data followed the Langmuir model (R2 = 0.99). The adsorption of RT and desorption of exchangeable cations from the clay mineral were linearly correlated, suggesting that cation exchange was the dominant mechanism of RT adsorption. The XRD examination of RT-adsorbed SAz-1 samples (unsaturated/saturated) after heating enabled the calculation of RT occupied area in the interlayer of the clay mineral. The results suggested that adsorbed-RT at low loading rate could lay on the internal surfaces in a free style to reduce the basal spacing (d 001 value) of SAz-1. When the RT loading rate was increased, a limited surface space enforced more RT molecules to lay in a tilted style and caused interlayer swelling of SAz-1 increasing the d 001 value. The trend of rising decomposition temperature of RT with increasing RT loading rates confirmed intercalation of RT molecules in SAz-1. Infrared spectral analysis revealed the participation of amide and furan groups of RT in binding between RT and SAz-1. Thus, this study indicated that SAz-1 is an efficient adsorbent to remove RT from contaminated water, and the chain-like molecular structure of RT could cause an irregular change in the basal spacing of swelling type clay minerals. [ABSTRACT FROM AUTHOR]

The cation‐exchange reaction (CER), a promising nanocrystal (NC) engineering strategy, has undergone rapid progress in the past decade, sparking a big wave of interest in the post‐synthetic tuning of chemical compositions, crystal phases, interfaces, morphologies, and corresponding properties. However, a significant gap has existed between the theoretical and actual CERs, hindering the popularization of CERs for explosive expansion in NC designs. A notable roadblock in this area has been the inability to control the site of cation exchange within the nanostructure, although partial cation exchange at desired sites can open an avenue to the vast structural diversity of nanostructures and accompany new physicochemical properties. Several notable successes have been recorded recently in fabricating predesigned hetero‐nanostructures by thoroughly understanding the principles of cation exchange and by exploiting the peculiarity of each crystal system. Herein, recent advances achieved in the CER are introduced, unraveling the critical factors controlling regiospecificity by analyzing the developed theories and accumulated experimental results. It is further described how this knowledge can be harnessed to design advanced NCs, and the beneficial effect of regiospecificity on material properties is highlighted. Finally, the challenges and research directions are provided to encourage further research in this burgeoning field. [ABSTRACT FROM AUTHOR]

This article describes a new technique for postsynthetic doping/alloying of Mn into ZnSe nanocrystals. The key feature is that it employs diethyldithiocarbamate anion to selectively bind the host cations and promote ion exchange. The presence of Mn in the product is confirmed with photoluminescence (PL) and total reflection X‐ray fluorescence spectroscopy. The cation exchange reaction takes place at temperatures as low as 100 °C. Higher temperatures allow to incorporate the impurity in greater quantities; however, after a crossover temperature of ≈200 °C, the process gets convoluted with Ostwald ripening and sulfide deposition, as evident from electron diffraction data, high‐resolution transmission electron microscopy (HR‐TEM), and elemental analysis of the samples. Studies of PL lifetime and quantum yield confirm these findings. Preliminary success is also shown for other impurities: Fe and Co are present in the respective samples in ≈17 at% of total metal content. [ABSTRACT FROM AUTHOR]

Urea oxidation reaction (UOR) with a low equilibrium potential offers a promising route to replace the oxygen evolution reaction for energy‐saving hydrogen generation. However, the overpotential of the UOR is still high due to the complicated 6e− transfer process and adsorption/desorption of intermediate products. Herein, utilizing a cation exchange strategy, Ni‐doped CuO nanoarrays grown on 3D Cu foam are synthesized. Notably, Ni‐CuO NAs/CF requires a low potential of 1.366 V versus a reversible hydrogen electrode to drive a current density of 100 mA cm−2, outperforming various benchmark electrocatalysts and maintaining robust stability in alkaline media. Theoretical and experimental studies reveal that Ni as the driving force center can effectively enhance the urea adsorption and stabilize CO*/NH* intermediates toward the UOR. These findings suggest a new direction for constructing nanostructures and modulating electronic structures, ultimately developing promising Cu‐based electrode catalysts. [ABSTRACT FROM AUTHOR]

• NaCl inhibited the growth and increased Na and Cl concentrations in rice leaves. • Application of Fe mitigated adverse effects of NaCl on rice growth. • Fe-supply enahnced plant antioxidant enzymatic activity in rice plants. • Fe-supply improved CEC of the soil and limited Na uptake by rice. Soil salinity affects plant growth and results in decreased agriculture productivity throughout the world. The present study was carried out to elucidate underlying mechanisms responsible for soil salinity tolerance in rice under the application of iron (Fe) as Fe(NH 4) 2 (SO 4) 2 ·6H 2 O. Rice seedlings were grown in pots containing soils (pH >8.0) and exposed to 0 and 150 mM (EC of 5.25 dS m−1) NaCl stress both with and without 0.5 mM Fe(NH 4) 2 (SO 4) 2 ·6H 2 O. Plant growth attributes like root length, shoot length, roots and shoots biomass, leaf chlorophyll contents, salt ions, plant mineral concentrations, plant antioxidant activities and cation exchange of soil were determined. Application of NaCl at the rate of 150 mM reduced the leaf chlorophyll contents (34%), root fresh and dry weights (39% and 45%), shoot fresh and dry weights (35% and 53%), grain yield (39%), potassium (K) (59% and 48%), calcium (Ca) (39% and 24%), and magnesium (Mg) (59% and 50%) concentrations in roots and leaves, whereas enhanced the sodium (Na) (537% and 500%) and chloride (Cl) (425% and 156%) accumulation both in roots and leaves as compared to control. Interestingly, Fe-supply enhanced the Fe uptake by rice plants and mitigated the adverse effects of salinity on rice growth and yield by 30%. Moreover, plant antioxidant enzymatic activity and cation exchange capacity (CEC) of soil (cmol Na+ kg−1) were enhanced by Fe-supply. In conclusion, Fe-application enhanced tolerance in rice due to down regulation of Na and up-regulation of Fe and antioxidant enzymatic activity in leaves. In addition, increased Na adsorption onto the surface of soils suggests that Fe competes with Na at soil-root interface, thereby limiting Na uptake by the plants. [ABSTRACT FROM AUTHOR]

Doping the semiconductor nanocrystals is one of the most effective ways to obtain unique materials suitable for high-performance next-generation optoelectronic devices. In this study, we demonstrate a novel nanomaterial for the near-infrared spectral region. To do this, we developed a partial cation exchange reaction on the HgTe nanoplatelets, substituting Hg cations with Pb cations. Under the optimized reaction conditions and Pb precursor ratio, a photoluminescence band shifts to ~1100 nm with a quantum yield of 22%. Based on steady-state and transient optical spectroscopies, we suggest a model of photoexcitation relaxation in the HgTe:Pb nanoplatelets. We also demonstrate that the thin films of doped nanoplatelets possess superior electric properties compared to their pristine counterparts. These findings show that Pb-doped HgTe nanoplatelets are new perspective material for application in both light-emitting and light-detection devices operating in the near-infrared spectral region. [ABSTRACT FROM AUTHOR]

The purpose of this work was to evaluate the ability of cation and actinide resins to isolate Be, Mn, Ni, and Cs from a mixed activation and fission product sample. Overall, the isolation of three fractions (Be/Mn, Cs, and Ni) was achieved via sequential cation and Actinide resin columns using non-radioactive surrogates and would potentially allow for quantitative analysis of select radioactive isotopes using single gamma ray energy analysis and ICP-OES. Recoveries of Mn and Be were comparable to those measured previously, although some co-elution of the Ni with the Cs fraction can occur. [ABSTRACT FROM AUTHOR]

To reduce the efflorescence extent of metakaolin (MK)-based geopolymer, this study introduced thermally activated modified calcium montmorillonite (MT) and 5 A zeolite (ZT) into MK-based geopolymer, and the optimal mixing ratio was acquired by response surface methodology. The effect of the two modified clay minerals on the microstructural and mechanical properties of the MT-ZT-MK geopolymer was explored by compressive strength testing, phase analysis (XRD and FTIR), pore structure analysis (MIP), and morphology analysis (SEM-EDS). To investigate the performance and mechanism of efflorescence inhibition of the ternary geopolymer, the cation concentration in the leaching solution was detected by inductively coupled plasma atomic emission spectrometry (ICP-OES), and the efflorescence area of the geopolymer was calculated using Image Pro Plus (IPP) software. The results of the experiment showed that the optimal mixing ratio, as determined by RSM, was 1.5 wt% of modified MT and 2.9 wt% of modified ZT, with the highest compressive strength at 65.1 MPa and the lowest degree of efflorescence after 28 days of curing. It can be concluded that the two clays gradually exhibit the effect of cation exchange and internal curing. The pore structure is optimized and (N, C)-A-S-H gels are formed with the extension of curing time. On the other hand, the lesser extent of efflorescence possibly is attributed to the restricted channels for Na+ in the matrix to undergo carbonation with CO 2 in the air. • Using thermally activated modified clay minerals to prepare ternary geopolymer. • The optimal mixing ratio of the ternary geopolymer is established by using RSM. • A proper content of modified clays is beneficial for the strength enhancement of geopolymers. • The mechanism of clay minerals to reduce efflorescence of geopolymers involves cation exchange and internal curing. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ionic liquid [HOEmim][NTf 2 ] can strengthen the extraction performance of TBP for Co2+. • The extraction efficiency of TBP/kerosene/[HOEmim][NTf 2 ] system for Co2+ is up to 99.6 %. • DFT calculations and FT-IR analysis indicate that Co2+ mainly binds to P=O in TBP. • A theoretical basis for removing Co2+ from waste water based on ionic liquids was laid. • ABSTRACT In order to achieve effective removal of radioactive Co(II) from the primary circuit wastewater of nuclear power plants and promote the safe use of nuclear energy, an efficient and eco-friendly method using ionic liquid as a co-extractant was proposed. The effects of ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 2 mim][NTf 2 ]) or 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([HOEmim][NTf 2 ]) as co-extractants on the extraction of Co(II) using tributyl phosphate (TBP) as an extractant were investigated in this work. The results reveal that the optimal extraction conditions for Co(II) are as follows: V TBP : V kerosene : V [HOEmim][NTf2] = 18:1:1, R(O/A) = 1, pH=4. Under these conditions, the extraction efficiency of Co(II) (E Co) reaches 99.6 %, with a distribution ratio (D Co) of 257. Notably, a single TBP or ionic liquid exhibits minimal ability to extract Co2+, while adding only 5 % (v/v) ionic liquid based on TBP/kerosene system can increase D Co by 104 times. The slope method and FT-IR analysis demonstrate that the TBP/kerosene/[HOEmim][NTf 2 ]/ system extracted Co2+ by a cation exchange mechanism. In addition, density functional theory (DFT) calculations were employed to explain the influence of different ionic liquid systems on the E Co , and further elucidate the extraction mechanism of Co2+. The striping results indicate that 92.2 % of Co2+ is stripped with 1.0 mol L−1 HNO 3. The extraction efficiency of Co(II) from the TBP/kerosene/[HOEmim][NTf 2 ] system remained at 98 % after 6 cycles. Therefore, the extraction system exhibits great practical potential in removing Co(II) from contaminated water. This work not only proposes an extraction system with excellent reusability and stability, but also lays a theoretical foundation for the ionic liquid-based cobalt extraction process. [ABSTRACT FROM AUTHOR]

The study presents a novel integrated three-compartment electrochemical continuous electrodeionization reactor that was constructed in a laboratory environment. In order to extract large amounts of carbon dioxide from naturally occurring oceanwater in the form of bicarbonate and carbonate, it develops a innovative electrolytic cation exchange process. At the same time, it produces hydrogen gas for possible hydrocarbon synthesis. The study employs the Box-Behnken experimental design approach implemented through the Design Expert software to investigate and optimize the performance of electrochemical hydrogen extraction from Ocean water from an integrated reactor. The integrated electrochemical continuous-type electrodeionization reactor comprises two cation-permeable membranes that operate as boundaries between three compartments: a central compartment and electrode compartments that house the cathode and anode, each of which may reverse polarity. These membranes are made of gel polystyrene cross-linked with divinylbenzene, which has acidic properties that allow cation transport while inhibiting anions. The integrated reactor's electrode chambers are enclosed in plexiglass end plates and contain distinct Plexiglass electrode compartments. These compartments have mesh and solid steel anode and cathode electrodes, with an electrode active area of 176.71 cm2. The influence of various factors, such as voltage and electrolyte amount, on the production of hydrogen synthesis is examined. The study results demonstrate a maximum hydrogen production rate of 2.2 mg/min and a hydrogen production efficiency of 7.82%. The lab testing was carried out using experimental equipment to determine viability. The tests included 35-min runs that measured hydrogen generation under various parameters, such as applied voltage, electrolyte concentration, and pH levels. The ocean salt solutions of 0.5M, 1M, and 2M were initially prepared and evaluated for hydrogen generation. Each concentration is assessed at a voltage range of 4–15V, with matching solution pH values ranging from 2 to 7. Optimization studies were conducted to enhance the hydrogen production rate. The results indicate that hydrogen production rises proportionally with applied voltage and electrolyte concentration but falls with pH growth. Within the Design Expert software, the statistical methods for response surface analysis and optimization are utilized accordingly. • The paper develops an integrated three-compartment system for hydrogen production. • The paper investigates the system overall efficiencies for assessment. • It discusses how varying voltage and concentration affects hydrogen production. [ABSTRACT FROM AUTHOR]

• Theoretical evaluation of protein separations by simultaneous independent pH & NaCl gradients. • Experimental demonstration of two dimensional LC pH & NaCl gradients. • Isocratic [NaCl] in pH gradients and vice versa vary MAb isoform retention times in WCX LC. • Separation of proteins by uncoupled pH and [NaCl] gradients enhances & improves resolution. • No one single set of uncoupled salt and pH gradients optimizes the resolution of all MAb isoforms. In previous publications we have described the pISep dual simultaneous, independent gradients (DSIGs) liquid chromatography (LC) for uncoupling gradients of non-buffering solute (NaCl, urea or acetonitrile) from externally generated pH gradients. In DSIGs the shape and slope of the [salute] gradient does not depend on the shape and slope of the pH gradient. The technique allows in a single run true simultaneous two dimensional LC separation of complex protein mixtures on various stationary phases including anion, cation exchangers (AEX, CEX), reversed phase (RP), mixed mode and mixed bed. Using a humanized IgG 1 (HIgG 1) monoclonal antibody (MAb) and a variety of pH & [NaCl] DSIGs, we show that most of MAb isoforms can be successfully separated from each other. These experimental observations are supported by an initial theoretical argument presented here predicting an overall improvement of all MAb isoforms separation by DSIGs of pH & [NaCl]. Theoretical calculations predict that, in general, there exists an optimal non-zero isocratic salt concentration in a pH gradient separation that will resolve isoforms close in binding energy, but a wide range of salt concentrations will be required for acceptable resolution of all isoforms. Theory also predicts better separation of weaker rather than stronger binding isoforms. Experimentally, we have found that no one set of DSIGs LC conditions could optimally baseline resolve all identifiable MAb isoforms in a single run of reasonable duration. The versatility and simplicity of the pH & [NaCl] pISep DSIGs LC allows fast, automated scouting of protein separations over any range of pH from 2.4 to 10.8 and [NaCl] from 0 to 1 M without changing the chemistry of the buffering system. Due to the universal applicability of the pISep buffering system in IEX LC, the researcher is given a powerful tool to easily develop pH & [NaCl] DSIGs protocols that vary mobile phase compositions to achieve high resolution separations of targeted proteins. [ABSTRACT FROM AUTHOR]

Currently, the deep geological repository approach for spent nuclear fuel is regarded as the most dependable and secure method for permanently disposing of this kind of waste. Among its key safety components is an engineered barrier made from compacted bentonite, which isolates the encapsulated waste from the surrounding host rock. As a result, understanding how bentonites react to varying compositions of groundwater is crucial. This is where numerical modelling becomes essential. It is generally approved by the scientific community to idealise bentonite as a material structured under a double porosity system composed of the macro and microstructure. In this context, this paper illustrates the capabilities of a double-porosity reactive transport model for bentonites fully implemented in the multiphysics COMSOL platform. For this purpose, different experimental tests were simulated based on the evaluation of diffusive ion transport, mineral dissolution and cation exchange processes in MX-80 bentonite, obtaining very satisfactory results. • A new reactive transport model for bentonites was implemented in COMSOL Multiphysics. • The model includes a geochemical system composed of 14 chemical species and gypsum. • The model considers diffusive-dispersive-advective transport in double-porosity media. • The model validation was run by 3 tests set in the Task Force on Engineered Barrier. [ABSTRACT FROM AUTHOR]

Direct Z‐scheme Cu7S4/CdS Janus photocatalysts are successfully prepared by cation exchange method. Extensive studies containing single‐nanoparticle impact electrochemistry are performed and reveal that optimizing the Cu7S4/CdS ratio can decrease the accumulation of holes on valence band of CdS for inhibiting photo‐corrosion and promote the accumulation of electrons on the conduction band of Cu7S4 for boosting the electron reducibility. With the optimized heterostructures, hydrogen evolution is remarkable promoted up to 21.62 mmol/g/h and quantum efficiency is up to 14.37% using polylactic acid plastic waste as feedstock. [ABSTRACT FROM AUTHOR]

[Display omitted] Catalytic hydrogenation reduction provides a potential route to detoxify nitro compounds. Spinel NiFe 2 O 4 (NiFeO) serves as a natural abundance and low-cost catalyst but suffers from low catalytic activity due to poor redox nature and limited active sites. Herein, defective MNiFeO (M = Cu, Zn, Co, Mn) nanorods (NRs) were synthesized by pyrolysis of cation-exchanged Fe 2 Ni-MOFs. The introduction of M modified the electronic structure of NiFeO and thus accelerated the electron transfer and proton transport in the hydrogenation of nitro aromatics. CuNiFeO exhibited the highest catalytic activity with a turn frequency of 2.89 × 105h−1, giving 308- and 422-fold larger than that of NiFeO-V o and NiFeO in the reduction of 4-nitrophenol (4-NP). CuNiFeO NRs also presented exceptional performances in the reduction of the other nitroarenes. The remarkable improvement in activity of mesoporous CuNiFeO may be attributed to its ternary composites, and increased oxygen vacancies. This work not only provides a simple route to constructing mesoporous MNiFeO NRs with oxygen vacancies, but also further discusses the effects of metal component and oxygen defects in the catalytic reduction of 4-NP. [ABSTRACT FROM AUTHOR]

Targeted Alpha Therapy (TAT) has shown very high potential for the treatment of cancers that were not responsive to other therapy options (e.g., β− therapy and chemotherapy). The main constraint to the widespread use of TAT in clinics is the limited availability of alpha-emitting radionuclides. One of the most promising candidates for TAT is 225Ac (t 1/2 = 9.92 days), which can be used directly in combination with selective biomolecules (e.g., antibodies, peptides, etc.) or be a generator source of 213Bi (t 1/2 = 45.6 min), another shorter-lived TAT radionuclide. Several strategies are currently under investigation to increase the supply of 225Ac. One of the most attractive options is the irradiation of natural thorium-232 targets with high-energy protons (≥100 MeV). However, there are several challenges associated with this production method including the development of an efficient radiochemical purification method. During irradiation of natural thorium with proton energy above 100 MeV, several Ra isotopes (223,224,225Ra) are produced. 223Ra (t 1/2 = 11.43 days) is used for the treatment of bone metastases and can also be used as a generator source for 211Pb. Additionally, 225Ra (t 1/2 = 14.9 days) can be a valuable source of isotopically pure 225Ac. In the present work, we address the radiochemical separation aspects of isolating Ac and Ra isotopes from irradiated thorium targets. [Display omitted] • Actinium-225 (t 1/2 = 9.92 d) is one of the most promising candidates for Targeted Alpha Therapy (TAT) • The irradiation of natural thorium with high energy protons can provide clinically relevant amounts of 225Ac/213Bi and 223Ra • Ac and Ra can be isolated from the bulk mass of Th(IV) and co-produced fission products via cation exchange chromatography in trichloacetic acid • DN Resin allows the purification of Ac from lanthanides [ABSTRACT FROM AUTHOR]

We report here fast A‐site cation cross‐exchange between APbX3 perovskite nanocrystals (NCs) made of different A‐cations (Cs (cesium), FA (formamidinium), and MA (methylammonium)) at room temperature. Surprisingly, the A‐cation cross‐exchange proceeds as fast as the halide (X=Cl, Br, or I) exchange with the help of free A‐oleate complexes present in the freshly prepared colloidal perovskite NC solutions. This enabled the preparation of double (MACs, MAFA, CsFA)‐ and triple (MACsFA)‐cation perovskite NCs with an optical band gap that is finely tunable by their A‐site composition. The optical spectroscopy together with structural analysis using XRD and atomically resolved high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) and integrated differential phase contrast (iDPC) STEM indicates the homogeneous distribution of different cations in the mixed perovskite NC lattice. Unlike halide ions, the A‐cations do not phase‐segregate under light illumination. [ABSTRACT FROM AUTHOR]

We report here fast A‐site cation cross‐exchange between APbX3 perovskite nanocrystals (NCs) made of different A‐cations (Cs (cesium), FA (formamidinium), and MA (methylammonium)) at room temperature. Surprisingly, the A‐cation cross‐exchange proceeds as fast as the halide (X=Cl, Br, or I) exchange with the help of free A‐oleate complexes present in the freshly prepared colloidal perovskite NC solutions. This enabled the preparation of double (MACs, MAFA, CsFA)‐ and triple (MACsFA)‐cation perovskite NCs with an optical band gap that is finely tunable by their A‐site composition. The optical spectroscopy together with structural analysis using XRD and atomically resolved high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) and integrated differential phase contrast (iDPC) STEM indicates the homogeneous distribution of different cations in the mixed perovskite NC lattice. Unlike halide ions, the A‐cations do not phase‐segregate under light illumination. [ABSTRACT FROM AUTHOR]

The sorption of 2-pyridinecarboxylic, 3-pyridinecarboxylic, and 4-pyridinecarboxylic acids by polystyrene sulfonic acid type cation exchange resin Dowex 50W-X8 and Dowex 50W-X4 from aqueous solutions was studied. Based on the analysis of the FT-IR spectra of acids, sulfates of their protonated forms, and an acid-saturated cation exchange resin, it was shown that pyridinecarboxylic acid is in the protonated form in the cation exchange phase. The equilibrium constants of sorption proceeding with participation of pyridinecarboxylic acid, sulfonic cation exchange resin, and proton were calculated according to experimental data on the equilibrium distribution of acids in the aqueous solution–cation exchange resin system. The values of the equilibrium constant of the cation exchange of the sulfonic ion-exchange resin proton by the pyridinecarboxylic acid cation from solution lie in the range 3.2–4.4. The equilibrium constants of sorption of 2-pyridinecarboxylic acid molecules are 25 dm3 mol–1, they increase to 195–220 dm3 mol–1 for 4-pyridinecarboxylic acid, and reach 320–330 dm3 mol–1 for 3-pyridinecarboxylic acid. Changing the amount of the cross-linking agent (from 4 to 8% divinylbenzene) in the polystyrene sulfonic acid type cation exchange resin does not significantly affect its sorption activity toward pyridinecarboxylic acids. [ABSTRACT FROM AUTHOR]

This paper demonstrates that intercalating Na+ homoionic vermiculite with Fe3+ polyhydroxy cations (1:1 molar ratio OH− to Fe3+) significantly improved the affinity of the clay mineral-based sorbent toward phosphate. Kinetic experiments revealed that adsorption is fast, approaching an equilibrium within about 200 min of contact time, and that the rate-limiting step is the intraparticle diffusion. Adsorption isotherms fitted to the Freundlich equation and a two-site Langmuir model, consistent with the heterogeneity of adsorption sites. The separation factor derived from the Langmuir constant revealed that the adsorption was favorable and even irreversible for high-affinity minor adsorption sites. The adsorption capacity was 299 ± 63 μmol g−1 (9.3 ± 2.1 mg P g−1), a value similar to several other clay-based phosphate adsorbents. Application to reservoir water spiked with 10 mg L−1 in P removed about 71% of the available phosphate. [ABSTRACT FROM AUTHOR]

Recently, many new, complex, functional oxides have been discovered with the surprising use of topotactic ion‐exchange reactions on close‐packed structures, such as found for wurtzite, rutile, perovskite, and other structure types. Despite a lack of apparent cation‐diffusion pathways in these structure types, synthetic low‐temperature transformations are possible with the interdiffusion and exchange of functional cations possessing ns2 stereoactive lone pairs (e. g., Sn(II)) or unpaired ndx electrons (e. g., Co(II)), targeting new and favorable modulations of their electronic, magnetic, or catalytic properties. This enables a synergistic blending of new functionality to an underlying three‐dimensional connectivity, i. e., [‐M−O‐M‐O‐]n, that is maintained during the transformation. In many cases, this tactic represents the only known pathway to prepare thermodynamically unstable solids that otherwise would commonly decompose by phase segregation, such as that recently applied to the discovery of many new small bandgap semiconductors. [ABSTRACT FROM AUTHOR]

Lithium (Li) isotopes have shown large potential in tracing weathering in various water bodies, but there is limited study on Li isotopes in subsurface conditions where CO 2 has been largely consumed. In this study, we use a thick sandstone aquifer in the Ordos Basin, NW China, as a natural setting to investigate the behaviors of Li isotopes in hydrogeochemical conditions with different concentrations of dissolved CO 2. For young groundwater in the recharge area (group R) where CO 2 is abundant (mean P CO2 = 10-2.5 atm), clay formation accompanying with weathering leads to the enrichment of 7Li in groundwater. The four deep samples in the recharge area have uniform Li/Na ratios (with a mean of 2.52 μmol/mmol) and δ7Li (with a mean of 25.0‰), corresponding to a mean Li removal rate of 81.2% compared with the sandstone leachate. For groundwater in the shallow part of the discharge area (group D1), Li was firstly removed by clay formation during weathering in the recharge area and was later removed by physisorption when CO 2 becomes much lower (mean P CO2 = 10-3.1 atm). Different degrees of weathering lead to a wide range of δ7Li varying from 19.7‰ in the deepest well to 33.0‰ in the shallowest well. The proportion of Li removal caused by physisorption is found to increase with groundwater age. After the stage of Li removal by adsorption, Li was released in the deeper part of the discharge area (group D2), and the positive correlation of δ7Li versus Li/Na is explained by a ternary mixing model. The endmember of water brought by cation exchange is inferred to have a heavier δ7Li than sandstone leachate, demonstrating that cation exchange could cause an enrichment of 7Li in water. This study enhances our understanding of the controlling factors of Li isotopes in deep groundwater with low dissolved CO 2 , which have implications for the application of Li isotopes in subsurface water. [ABSTRACT FROM AUTHOR]