Ion Exchange Layer Research Articles

Quenching of silver clusters luminescence by Eu(III) and Sm(III) ions in ion-exchanged layers of silica-based glass

Series of silica-based glasses doped with La2O3, Eu2O3, and Sm2O3 was synthesized to host luminescent silver clusters formed via Na+-Ag+ ion exchange and heat treatment. Photoluminescence spectra of the glasses with Eu3+ or Sm3+ ions consist of broad white emission from silver clusters and characteristic bands of rare-earth ions. Energy transfer between silver clusters and Eu3+ or Sm3+ ions was studied by controlling luminescence quantum yield and lifetime of silver clusters. Rare-earth doping of the studied glass decreases the amount of forming silver clusters, therefore, the quenching efficiency of Eu3+ and Sm3+ ions was calculated in comparison to the glasses doped by La3+. It was shown that quantum yield of cluster luminescence decreases faster than the fluorescence and phosphorescence lifetime in the presence of Eu3+ or Sm3+ ions. Difference in quenching efficiency of luminescence quantum yield and emission lifetime of silver clusters was explained by the coexisting of two different mechanisms of quenching.

Bipolar Membranes Via Divergent Synthesis: On the Interplay between Ion Exchange Capacity and Water Dissociation Catalysis.

Bipolar membranes (BPMs) enable the operation of electrochemical reactors with electrode compartments in different chemical environments or pH. The transport properties at the microscopic scale are dictated by the composition and morphology of the interfacial junctions as well as the specific chemistry of the ion-exchange layers that support the current of protons and hydroxide ions. This work elucidates the relation between water-dissociation efficiency and the physicochemical properties of the individual ion-exchange membrane layers in the poly(styrene-b-poly(ethylene-ran-butylene)-b-polystyrene) (SEBS)-based BPM. The optimal water dissociation performance of three previously reported water-dissociation catalysts in the SEBS-based BPM was examined, with junction thickness of graphene oxide > TiO2 > SnO2, resulting in disparate junction morphologies at the BPM's interface. A hybrid junction system, which included both the effective water dissociation catalyst SnO2 and direct contacting of the ion-exchange membrane layer, exhibited high water dissociation efficiency. This was likely due to the immediate ion transport pathway provided by direct membrane contact around the catalyst, which also improved the interfacial adhesion. A higher ion exchange capacity (IEC) in BPMs substantially enhanced the water dissociation performance in BPMs without water-dissociation catalysts. However, the incorporation of the effective SnO2 catalyst into the BPMs with a lower IEC significantly improved performance, an effect attributed to the hybrid junction system. Additionally, the increase in water uptake and ion conductivity of the cation exchange layer with higher IEC suggested that the cation exchange layer and its interface to the water-dissociation catalyst layer may play a key role in water dissociation. This study identifies the key parameters of individual BPM components and their interactions to water dissociation performance, offering new insights to guide in the construction of future BPMs optimized for enhanced water dissociation efficiency at high current densities.

Mechanical behavior and biological activity performance of Li+/Ca2+@Li+/K+ ion-exchanged lithium disilicate glass-ceramics

Lithium disilicate (LD) glass-ceramics used for bone repair need to have good mechanical properties and biological activity. Ion-exchange can lead a significant surficial strengthening and bioactivity of LD glass-ceramics. In this work, LD glass-ceramics were Li+/Ca2+@Li+/K+ exchanged in a mixed salt bath of 30 % Ca(NO3)2 + 70 % KNO3 (in mol %) at 400 °C for 16 h, 32 h and 64 h respectively. LD glass-ceramics were significantly strengthened after Li+/Ca2+@Li+/K+ exchange. However, due to the shallow depth of the ion-exchange layer and stress relaxation, the strengthening effect deteriorated with the prolongation of the ion-exchange time. The Li+/Ca2+@Li+/K+ exchanged LD glass-ceramics could be conducive to the formation of the hydroxyapatite (HA) after soaking in the simulated body fluid (SBF). Moreover, the protein adsorption, cytotoxicity, cell adhesion, osteoblast proliferation and alkaline phosphatase (ALP) activity expression of Li+/Ca2+@Li+/K+ exchanged LD glass-ceramics were investigated. Ca2+ release might promote the bioactivity of ion-exchanged LD glass-ceramics. Therefore, Li+/Ca2+@Li+/K+ exchange can improve the mechanical properties and bioactivity of LD glass-ceramics, which has important significance for its application in orthopedic reconstruction.

Selecting optimal carbon inks for fabricating high-performance screen-printed electrodes for diverse electroanalytical applications

Carbon-based screen-printed electrodes (SPEs) are extensively employed in electrochemistry due to their reproducibility, low-cost production, disposability and versatility. It is commonly accepted that batch to batch variations may occur due to variations in the ink formulation or the use of a different ink to print the electrodes. In this paper, three different commercial carbon-based inks (DuPont, Loctite and SunChemical) were used to manufacture SPEs, referred to respectively as Dup-SPE, Loc-SPE and Sun-SPE, using a semi-automated screen-printing technology. This study focuses on evaluating the quality, characteristics and electrochemical performance of the fabricated SPEs. Furthermore, the study aimed to investigate potential correlations between the ink composition and the nature of different target molecules, as well as their electroanalytical responses. Specifically, phenolic compounds and cocaine cutting agents are tested in alkaline conditions, while benzodiazepines and cephalosporine antibiotics are investigated in acidic media using square wave voltammetry (SWV). This aims to extract insights for the proper selection of inks and SPEs in both conditions. Additionally, a scan rate study of cephalosporine antibiotics using linear sweep voltammetry (LSV) is performed confirming the ion-exchange polymer layer on the electrode surface of Loc-SPE, which impact surface and electrochemical properties, leading to drawbacks in alkaline SWV sensing, but strategic benefits in reductive sensing resulting in an enhanced selective detection of specific targets. The insights on ink-specific influences on the surface and electrochemical properties of the SPEs obtained, may be useful for facilitating the electrode selection in diverse electrochemical applications, emphasizing the critical role of ink composition in achieving desired sensing capabilities.

Spectral selectivity of luminescence of a copper ion-exchange layer in sodium-potassium-magnesium silicate glass

The bright luminescence of the copper ion-exchange layer in glass has potential applications as a converter of electric spark and corona discharge radiation in devices for the rapid analysis of metals because of its selectivity. The selectivity of the luminescence of the copper ion-exchange layer was achieved by the presence of different luminescent centers within it. In this work, the copper monomers, Cu+-Cu+ monovalent dimers, and Cun molecular clusters were formed in an ion-exchange layer of sodium-potassium-magnesium silicate glass (SiO2-Na2O-CaO-MgO-Al2O3-K2O-Fe2O3). The luminescence of the copper ion exchange layer was characterized by steady-state spectroscopy and time-resolved spectroscopy. Molecular copper clusters Cun exhibited luminescence in the nanosecond range, and Cu+ monomers and Cu+-Cu+ monovalent dimers in the microsecond range, respectively. At the same time the formation of divalent copper led to a limitation in the duration of ion exchange for the production of luminescent glasses. Heat treatment of the ion-exchange layers led to an increase in the concentration of molecular copper clusters, Cu+-Cu+ monovalent dimers, and Cu2+ divalent monomers.

Development of High-Performance Bipolar Membranes with Optimal Junction Properties for Efficient Electro-Membrane Processes

A bipolar membrane (BPM) is a special type of ion-exchange membrane in which an anion-exchange layer (AEL) and a cation-exchange layer (CEL) are combined. Water molecules can be easily dissociated at the interface of the BPM by the strong electric field generated when a reverse bias voltage is applied through the membrane. Such dissociation leads to the generation of proton and hydroxide ions, which are then transported through the CEL and AEL, respectively, resulting in the production of acid and base solutions. Under a forward bias, these ions are drawn back to the bipolar interface, where they neutralize each other. The energy derived from this neutralization process, represented as a junction potential (JP) value, is a key factor in the BPM's efficiency. BPMs with ideal JP values are critical for achieving high separation and energy efficiencies in electro-membrane processes. Furthermore, for the prolonged operation of these processes, BPMs must possess a highly adhesive bipolar junction. Our work includes the development of a novel BPM with an ideal JP and a highly adhesive bipolar junction. This BPM has been applied to various electro-membrane processes, including an acid-base flow battery and direct seawater electrolysis. The BPMs are fabricated using poly(phenylene oxide) (PPO)-based ionomers, and incorporates an iron-based catalyst and a reinforcing material. These additions enhance the water-splitting performance and the durability of the interface between the ion-exchange layers. The prepared BPMs not only demonstrated excellent interfacial adhesiveness and mechanical properties but also achieved a water-splitting efficiency of 98% or higher. In comparison to commercial BPM, the electro-membrane processes utilizing the prepared BPM exhibited superior performance. This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Korean government (MEST) (NRF-2022M3C1A3081178 & NRF-2022M3H4A4097521).

Potential oscillation enhanced lithium ion pump membrane for lithium ion extraction

In this work, a novel electrochemically switched ion permselective membrane (ESIPM) has been applied to the recovery of lithium from brine in the electrochemically switched ion permselective (ESIP) membrane separation system. This ESIPM was prepared by multi-layer assembly, with polyacrylonitrile ultrafiltration membrane (PAN) as the base membrane, and CNTs/CS membranes pressed and filtered on the base membrane as the current collector, crosslinking a lithium manganate/carbon black/polyvinyl alcohol/polyacrylic acid (LiMn2O4/C/PVA/PAA) composite material, which coated on a polyacrylonitrile ultrafiltration membrane/carbon nanotubes (PAN/CNTs) composite membrane as the electroactive lithium ion exchange layer. In the ESIP system, by alternately applying oscillation potentials between the ESIPM membrane and counter-electrodes to regulate the placement and release of the target ions on the membrane, Meanwhile the target ions are driven by the electric field to be enriched in the ESIPM and directionally transported through the ESIPM. As a result, it was found that compared with the electrodialysis (ED) system, the flux of Li+ in ESIPM in the ESIP system increased by 12 times and the selectivity factor for Li+/Mg2+ increased by 1.4 times for the brine with Mg2+/Li+=1. Besides, the selectivity factor for Li+/Mg2+ reaches 4.4 for the brine with Mg2+/Li+=20 in ESIPM in the ESIP system, which was 2.2 times higher than that of the commercial ion exchange membrane CIMS in the ED system.

The impact of membrane orientation on ion flux in bipolar membranes

Bipolar membranes (BPMs) are asymmetric, layered ion exchange membranes that are increasingly being explored for use in electrochemical devices. This study aims to investigate the effect that the direction of a diffusive driving force across a salt solution concentration gradient has on the flux through a BPM due to its asymmetric nature. BPMs were fabricated using PiperION poly(aryl piperidinium) A40 as the anion exchange layer (AEL) and Nafion 212 as the cation exchange layer (CEL) with no interfacial junction catalyst. The permeability of sodium chloride through the BPM membranes was measured across a 0.5molL-1 concentration differential for both orientations of the membrane, e.g. AEL facing the 0.5molL-1 NaCl solution versus the CEL facing the 0.5molL-1 NaCl solution. A flux differential of (76.3 ± 4.8)% was measured for the BPM depending on the direction of the driving force. A model based on Fick’s law and the Donnan equilibrium was developed and used to show that the flux differential results from changes in the ionic environment at the AEL–CEL junction due to differences in the ion diffusion coefficients and fixed charge concentrations of the two layers.

Biosurfactants—An Overview

AbstractThe large structural and functional variety of bio‐surfactants (BS), which are produced by microorganisms, leads to the use of several methods to study these amphiphilic molecules. This review seeks to consolidate information on various surface‐active product extraction techniques, microbiological screening methodologies, and analytical terminologies utilized in this sector. The potential benefits and drawbacks of various approaches for studying cell biomass or microbial culture broth for the generation of surface‐reactive chemicals are also discussed. Additionally, the most popular techniques for detection, structural characterization, and purification of a variety of BS are introduced. A number of straightforward techniques are described in detail, including dialysis, ion exchange, solvent extraction, ultrafiltration, lyophilization, and thin layer chromatography (TLC). In addition to more sophisticated techniques like nuclear magnetic resonance (NMR), fast atom bombardment mass spectroscopy (FAB‐MS), gas chromatography‐mass spectroscopy (GC‐MS), high‐pressure liquid chromatography (HPLC), and infrared (IR), proteolysis and sequencing of amino acid are also explained. In this field of study, it is quite necessary to combine several analytical techniques, and it often takes multiple iterations to purify, isolate, and characterize different surface‐active substances. The numerous approaches that are essential for researching bio‐surfactants are covered in this review.

Formation and Photophysical Properties of Silver Clusters in Bulk of Photo-Thermo-Refractive Glass

The bright luminescence of silver clusters in glass have potential applications in solid-state lighting, optical memory, and spectral converters. In this work, luminescent silver clusters were formed in the bulk of photo-thermo-refractive glass (15Na2O-5ZnO-2.9Al2O3-70.3SiO2-6.5F, mol.%) doped with different Ag2O concentrations from 0.01 to 0.05 mol.%. The spontaneous formation of plasmonic nanoparticles during glass synthesis was observed at 0.05 mol.% of Ag2O in the glass composition, limiting the silver concentration range for cluster formation. The luminescence of silver clusters was characterized by steady-state and time-resolved spectroscopy techniques. The rate constants of fluorescence, phosphorescence, intersystem crossing, and nonradiative deactivation were estimated on the basis of an experimental study. A comparison of the results obtained for the photophysical properties of luminescent silver clusters formed in the ion-exchanged layers of photo-thermo-refractive glass is provided.

Influence of silver nanoparticles in the ion-exchange layer of photo-thermo-refractive porous glass on the spectral-luminescent properties of CsPbBr3 perovskite nanocrystals

The spectral-luminescent properties of new composite materials based on porous matrices of photo-thermo-refractive glasses with a silver ion-exchange layer and CsPbBr3 inorganic perovskite nanocrystals have been studied. Perovskite nanocrystals were introduced into a porous matrix by the method of pumping solutions through a sample under piston pressure. Two mechanisms of interaction between silver nanoparticles and perovskite nanocrystals have been revealed, such as enhancement of the local field and luminescence quenching due to the high absorption of nanoparticles. The quantum yield of the studied samples under different irradiation associated with an increase in the concentration of silver nanoparticles was 34% without irradiation, 51% with 100 j irradiation dose, and 25% with 1000 j irradiation dose. In this case, an increase in the integrated luminescence intensity was observed in glasses irradiated with 100 J by a factor of 2.97 and irradiated with 1000 J by a factor of 1.76 compared to the unirradiated sample. The average luminescence lifetime decreases from 2.19 to 1.68 ns with an increase in the concentration of nanoparticles.

Design of injected water salinity for enhanced oil recovery applications in sandstone reservoirs using coupled flow-geochemical simulation

Many previous studies have highlighted the effect of injected fluid salinity on recovery performance and effluent analysis in sandstone reservoirs. However, the complex interactions between the oil, original formation water, injected water, and rocks make capturing all the relevant mechanisms difficult. This paper presents a simulation study where complex mechanisms and interactions are represented, including multiple ion exchange, mineral dissolution, wettability alteration, pH variation, and electrical double layers. The models are used to examine how the salinity of injected water may affect oil recovery and compositions of the effluent fluids. The results show that the wettability changes caused by ion exchange and mineral dissolution/precipitation reactions may strongly affect the recovery performance of low-salinity water injection. In contrast, mineral dissolution/precipitation effects are less significant for high-salinity water injection. In addition, the complex interactions between these processes also affect the pH in the effluent (producing) streams.

Computational Design of an Electro-Membrane Microfluidic-Diode System.

This study uses computational design to explore the performance of a novel electro-membrane microfluidic diode consisting of physically conjugated nanoporous and micro-perforated ion-exchange layers. Previously, such structures have been demonstrated to exhibit asymmetric electroosmosis, but the model was unrealistic in several important respects. This numerical study investigates two quantitative measures of performance (linear velocity of net flow and efficiency) as functions of such principal system parameters as perforation size and spacing, the thickness of the nanoporous layer and the zeta potential of the pore surface. All of these dependencies exhibit pronounced maxima, which is of interest for future practical applications. The calculated linear velocities of net flows are in the range of several tens of liters per square meter per hour at realistically applied voltages. The system performance somewhat declines when the perforation size is increased from 2 µm to 128 µm (with a parallel increase of the inter-perforation spacing) but remains quite decent even for the largest perforation size. Such perforations should be relatively easy to generate using inexpensive equipment.

Enhanced corrosion resistance and biofunctionality of Zn–Al layered double hydroxide coating on micro-arc oxidized ZK60 Mg alloy via ion exchange

In this work, zinc-aluminum layered double hydroxides (Zn–Al LDHs) were prepared on the surface of micro-arc oxidized ZK60 magnesium (Mg) alloy by a hydrotreatment in a Zn(NO3)2 solution. Scanning electron microscopy, X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), laser scanning confocal microscopy and Fourier-transform infrared spectroscopy (FT-IR) were applied to analyze the coating characteristics. Ion exchange experiments were performed on the optimized LDHscoatings with 0.1 M methionine (Met) and cysteine (Cys) solution for 4 h at 60 °C. Methionine and cysteine were successfully inserted into the interlayer structure of LDHs. The LDHs-Met and LDHs-Cys coatings are distributed in a petal shape by hexagonal nanosheets, and their distributions on the surface of the MAO are dense and uniform. The porosity, surface roughness, hydrophilicity, and corrosion resistance of LDHs-Met and LDHs-Cys coatings are increased compared to MAO and MAO/LDHs coatings. The amino acids in the LDHs could play an influential corrosion inhibition role, improving the corrosion resistance of the MAO effectively. The ion exchange layer has a more substantial protective effect on the substrate and better biocompatibility than MAO and MAO/LDHs coatings.

Vanadium Oxide Nanosheet-Infused Functionalized Polysulfone Bipolar Membrane for an Efficient Water Dissociation Reaction.

A high-performing bipolar membrane (BPM) was fabricated using functionalized polysulfones as the ion-exchange layers (IELs) and two-dimensional (2D) V2O5-nanosheets blended with polyvinyl alcohol (PVA) as the water dissociation catalyst (WDC) at the interfacial layer. The composite BPM showed a low resistance of 0.79 Ω cm2, confirming the good contact between the IEL and WDC, much needed for the ionic conductivity. It also demonstrated high water dissociation performance with a water dissociation voltage of 1.11 V corresponding to a current density of 1.02 mA/cm2 in the presence of a 1 M NaCl electrolytic solution. The functionalization of the polysulfone with -SO3- and R4N+ groups successfully resulted in the increase of hydrophilicity of the polymer, thereby increasing the water uptake capacity of the membranes. The blending of 2D V2O5 nanosheets with PVA proved to be an effective WDC, as confirmed by the increased conductivity and efficiency of the water dissociation (WD) reaction. The 2D V2O5-ns have great potential toward water adsorption onto its surface, thereby interacting with the water molecules, weakening the bonding force of water, and dissociating it into H+ and OH-. The transportation of coions across the membranes and generation of protons and hydroxyl ions at the interfacial layer are correlated with the change in the pH of the catholyte and anolyte as a function of current density during the WD reaction. The high performance of the composite BPM (BPM_VO-ns) was demonstrated at a higher current density of 100 mA/cm2 with a WD resistance of 0.027 Ω cm2. The durability was tested by subjecting it to 45 h of run at lower (1.02 mA/cm2) and higher (100 mA/cm2) current densities which display a negligible change in the interlayer voltage. Thus, the fabricated composite BPMs pave the way to be utilized for efficient and durable WD reactions under neutral electrolytic conditions.

H3PO4-Induced Nano-Li3PO4 Pre-reduction Layer to Address Instability between the Nb-Doped Li7La3Zr2O12 Electrolyte and Metallic Li Anode

Solid-state batteries based on a metallic Li anode and nonflammable solid electrolytes (SEs) are anticipated to achieve high energy and power densities with absolute safety. In particular, cubic garnet-type Nb-doped Li7La3Zr2O12 (Nb-LLZO) SEs possess superior ionic conductivity, are feasible to prepare under ambient conditions, have strong thermal stability, and are of low cost. However, the interfacial compatibility with Li metal and Li dendrite hazards still hinder the applications of Nb-LLZO. Herein, a quick and efficient solution was applied to address this issue, generating a nano-Li3PO4 pre-reduction layer from the reaction of H3PO4 with the ion-exchanged passivation layer (Li2CO3/LiOH) on the surface of Nb-LLZO. A lithiophilic, electrically insulating interlayer is in situ created when the Li3PO4 modified layer interacts with molten Li, successfully preventing the reduction of Nb5+. The interlayer, which mostly consists of Li3P and Li3PO4, also has a high shear modulus and relatively high Li+ conductivity, which effectively inhibit the growth of Li dendrites. The Li|Li3PO4|Nb-LLZO|Li3PO4|Li symmetric cells stably cycled for over 5000 h at 0.05 mA cm-2 and over 1000 h at a high rate of 0.15 mA cm-2 without any short circuits. The LiFePO4 and S/C hybrid solid-state batteries using the modified Nb-LLZO electrolyte also demonstrated good electrochemical performances, confirming the practical application of this interfacial engineering in various solid-state battery systems. This work offers an efficient solution to the instability issue between the Nb-LLZO SE and metallic Li anode.

A Study on the Structure and Biomedical Application Characteristics of Phosphate Coatings on ZKX500 Magnesium Alloys.

Magnesium-matrix implants can be detected by X-ray, making post-operative monitoring easier. Since the density and mechanical properties of Mg alloys are similar to those of human bones, the stress-shielding effect can be avoided, accelerating the recovery and regeneration of bone tissues. Additionally, Mg biodegradability shields patients from the infection risk and medical financial burden of needing another surgery. However, the major challenge for magnesium-matrix implants is the rapid degradation rate, which necessitates surface treatment. In this study, the ZKX500 Mg alloy was used, and a non-toxic and eco-friendly anodic oxidation method was adopted to improve corrosion resistance. The results indicate that the anodic coating mainly consisted of magnesium phosphate. After anodic oxidation, the specimen surface developed a coating and an ion-exchanged layer that could slow down the degradation and help maintain the mechanical properties. The results of the tensile and impact tests reveal that after being immersed in SBF for 28 days, the anodic oxidation-treated specimens maintained good strength, ductility, and toughness. Anodic coating provides an excellent surface for cell attachment and growth. In the animal experiment, the anodic oxidation-treated magnesium bone screw used had no adverse effect and could support the injured part for at least 3 months.

Tradeoff between the Ion Exchange-Induced Residual Stress and Ion Transport in Solid Electrolytes

Rapid filament growth of lithium is limiting the commercialization of solid-state lithium metal anode batteries. Recent work demonstrated that lithium filaments grow into pre-existing or nascent cracks in the solid electrolyte, suggesting that increasing the fracture toughness of the solid electrolytes will inhibit filament penetration. It has been suggested that introducing residual compressive stresses at the surface of the solid electrolyte can provide this additional fracture toughness. One of the ways to induce these residual compressive stresses is by exchanging lithium ions (Li+) with larger isovalent ions such as potassium (K+). On the other hand, incorporation of too much potassium can alter the lithium-ion diffusion pathway and lower the diffusivity, thus limiting the performance of the solid-state electrolyte. Using multiscale modeling methods, we optimize this tradeoff and predict that exchanging 3.4% potassium ions up to a depth twice the grain sizes in Li7La3Zr2O12 solid electrolyte can induce a maximum residual compressive stress of around 1.1 GPa, corresponding to an increase in fracture strength by ∼8 times, while lowering the diffusivity in the ion-exchanged region by a factor of 5 at room temperature. The reduction of lithium diffusivity is due to K+-induced stress and (mainly) blockage of lithium ion pathways in the shallow ion-exchanged layer.

Removing miscellaneous heavy metals by all-in-one ion exchange-nanofiltration membrane

The composition of wastewater containing heavy metal mixtures is often complex and poses a serious threat to human and environmental health. Effective removal of a variety of heavy metal ions with a single technology is challenging, and the conventional split integrated technologies require multi-step processing and a massive footprint. For the first time, we achieve hierarchically integrating ion exchange and nanofiltration into all-in-one “iNF” membranes. The iNF membrane has a hierarchical structure with an interfacial polymerization layer and an ion exchange layer, which can achieve highly efficient indiscriminate heavy metal ion removal, overcoming the defect that traditional nanofiltration membranes can only remove single metal cations or oxyanions. The ion exchange layer can remove heavy metal ions through sulfonic acid groups and quaternary amine groups. In addition, the ion exchange layer can be regenerated by electro-deionization, which is meaningful for sustainable membrane usage. This facile, scalable, and compact integrated process shows outstanding potential and universal applicability in complex wastewater treatment.

Photocatalytic properties of Ag-AgBr nanostructures in ion-exchanged layers of bromide sodium-zinc-aluminosilicate glass matrix

The photocatalytic properties of Ag–AgBr nanostructures formed by low-temperature ion exchange method and followed heat-treatment in bromide sodium-zinc-aluminosilicate glass have been investigated. Glasses based on Na2O–ZnO–Al2O3–SiO2 system and doped with Sb2O3, Ce2О3 and Br were synthesized. Layers containing silver ions were formed on the surface of sodium-zinc-aluminosilicate glass by the ion exchange method. The glass samples were immersed in a bath containing a melt of nitrate mixture 5AgNO3/95NaNO3 (mol%) at 320 °C for 2 hours. Subsequent heat treatment at 500 °C resulted in a formation of Ag–AgBr nanostructures in the surface layer. The photocatalytic properties of the Ag–AgBr nanostructures on the glass surface were measured by the decomposition of the methyl orange dye. A comprehensive study of the spectral and photocatalytic properties of Ag–AgBr nanostructures has been carried out. It was shown that, after ion exchange and heat treatment, the AgBr crystal shells with a size of 6 nm were formed around silver nanoparticles. It has been established that the presence of a photocatalyst with Ag–AgBr nanostructures in the surface layer of glass under ultraviolet irradiation leads to degradation of the methyl orange dye by 77 %. Reducing the thickness of the ion-exchange layer to 5 μm by chemical etching decreased the degradation efficiency of the methyl orange dye to 15 %. The results of the work can be applied in devices for the photocatalytic decomposition of water to produce hydrogen.