This study investigates the fluorescent and mesomorphic properties of tetrakis(oxadiazolyl)benzenes (TOBEs) and -pyrazines (TOPYs), novel cruciform liquid crystals. The impact of a set of four side chains on optical and mesomorphic properties is reported. TOBE absorbs in the UV range (~360 nm), while substituting the central benzene ring by pyrazine (TOPY) shifts the absorption maximum to 396 nm but lowers the fluorescence quantum yield (TOBE: 72%; TOPY: 21%; in toluene). Fluorescence in the green-to-orange range is influenced by solvent polarity. Mesophase analysis shows quite narrow phases (~20 K) for TOBE. As the pyrazine core lowers the melting point and elevates the clearing temperature, huge mesophase ranges (~80–90 K) are detected for TOPY. Side chain variations further influence material properties: TOBE with linear alkyl chains exhibits multiple crystal–crystal transitions, while branching enhances mesophase stability and alters fluorescence characteristics. The Huisgen reaction provides a cost-effective synthetic route for these fluorescent mesogens, offering high yields and efficiency.
Dewar–Chatt–Duncanson (DCD) model has been the celebrated model in describing metal–ligand donation and backdonation. However, this runs counter in the case of M-diborene and M-diboron complexes with early transition metals where B-B bond strengthening has been observed. However, the present study reveals that with late transition metals, the usual DCD model is preserved and the weakening of B-B bond in MB2 complexes (M = Ni, Pd, Pt) is observed. Electronic structure analysis has rationalized the opposite bonding scenario. Interestingly, all these MB2 (M = late transition metals) species are found to possess Möbius aromaticity while the early transition metal MB2 complexes are Hückel aromatic.
Lethal foodborne illness outbreaks represent a critical intersection of public health surveillance, environmental health, and forensic toxicology. When acute gastrointestinal syndromes lead to sudden death, traditional postmortem investigation techniques are often hindered by tissue autolysis and the overgrowth of putrefactive microflora, which complicate conventional microbiological assays. This review establishes a comprehensive framework for chemical forensics by evaluating the utility of stable isotope analysis (SIA) as a supportive, probabilistic chemical proxy to complement traditional epidemiological investigations of postmortem food contamination sources. Following JBI scoping review guidelines and the PRISMA-ScR reporting framework, data from 42 peer-reviewed articles (2000–2026) were charted and synthesized to map natural isotopic variations (δ13C, δ15N, δ18O, δ2H and δ34S) across both forensic decedents and environmental reservoirs. The findings outline a structured, multi-tissue diagnostic cascade governed by biological metabolic turnover rates: unabsorbed gastric chyme provides a direct chemical match to contaminated source food items within a hyper-acute 0–6 h window; high-turnover visceral matrices (liver, blood plasma) shift to reflect acute exposure profiles within 1–7 days; and continuously fixed keratinized matrices (hair, nails) archive multi-month dietary and transcontinental transit histories. Furthermore, compound-specific isotope analysis (CSIA) of individual amino acids offers unprecedented structural resolution, utilizing the carbon discrimination metric (Δ13Cglu-phe) to differentiate pristine agricultural signatures from endogenous metabolic distortions while biochemically verifying pre-mortem physiological stress and hyper-catabolic muscle wasting. Taphonomic thresholds were explicitly defined, establishing that bulk visceral soft tissues remain isotopically stable (±0.3‰) for up to 48 h at room temperature (~21 °C) before microbially induced nitrogen enrichment (δ15N > +2.8‰) alters native profiles, whereas hair and nail keratin maintain absolute isotopic stability for over 180 days postmortem. When pristine multi-isotope signatures are coupled with mandatory chloroform–methanol lipid extraction and processed through spatial Bayesian assignment models, geographic provenance tracking via environmental isoscapes achieves a predictive accuracy of 97%. This review introduces a standardized environmental health protocol designed to harmonize field environmental sampling with medical autopsies. This protocol provides a legally robust strategy for investigating unresolved lethal foodborne illness case-outbreaks, particularly those involving pediatric mortalities linked to the consumption of counterfeit or fraudulent food products in low- and middle-income countries. Furthermore, it aims to strengthen national and municipal legal frameworks and international biosecurity enforcement.
The crystal structure and physicochemical properties of a new Ni/Zn codoped bismuth antimonite pyrochlore, synthesized by the solid-phase reaction method, were investigated. The most optimal outcomes of Rietveld refinement for Bi2.7Zn0.46Ni0.70Sb2O10+Δ were achieved for the model of a disordered pyrochlore structure (sp.gr.Fd-3m:2, a = 10.46442(5) Å). Zinc and nickel atoms demonstrate an inhomogeneous mixed distribution across bismuth and antimony positions. The microstructure of the ceramic is characterized by low porosity, and is formed by faceted grains of 0.25–2 μm in diameter. The thermal expansion coefficient (TEC) increases monotonically from 7.14 × 10−6 °C−1 (30 °C) to 9.80 × 10−6 °C−1 (990 °C). At temperatures above 1080 °C, an atypical thermal dissociation of the pyrochlore occurs, resulting in the formation of bismuth-free compounds and two cubic phases that are stable when the sample is cooled. The Bi2.7Zn0.46Ni0.70Sb2O10+Δ compound is characterized by a band gap width of 2.4 eV. At temperatures below 200 °C, the sample exhibits predominantly capacitive impedance characteristics. The capacitance remains constant and independent of temperature and frequency up to a maximum of 150 °C. The high-frequency relative dielectric permittivity is low and equal to 26(3). The conduction activation energy in the sample is found to be 1.30(5) eV. Two polarization processes are detected in the sample. The electrical behavior of the sample has been modeled successfully by equivalent circuits within the temperature range of 200–450 °C. According to NEXAFS and XPS data, metal cations exhibit a conventional charge state, with an antimony oxidation state of +(5−δ).
Geogenic processes and human activities are both major causes of soil pollution. Soils can get toxic transition metals from the materials they are formed from, but most pollution comes from industrial and farming activities. The presence of these transition metals in soil can be shown through changes in chemical, biochemical, and microbial properties, as well as how plants react. This research aims to remove transition metals like chromium (Cr), manganese (Mn), iron (Fe), zinc (Zn), tungsten (W), and cadmium (Cd) from soil using a boron nitride (BN) nanocage. The electromagnetic and thermodynamic properties of these metals when trapped in BN were studied using materials modeling. The metals are captured through chemisorption. The research looked at how Cr, Mn, Fe, Zn, W, and Cd are trapped by BN to detect soil metal cations. BN was designed in the presence of these transition metals. The covalent characteristics of these complexes show similar energy levels and a view of the partial density of states between the p states of boron and nitrogen in BN and the d states of Cr, Mn, Fe, Zn, W, and Cd in B(X)N complexes. Also, nuclear magnetic resonance (NMR) analysis showed clear peaks around Cr, Mn, Fe, Zn, W, and Cd when they were trapped in BN during atomic detection and removal from soil, although there were some variations in chemical shielding for isotropic and anisotropic tensors. Based on these results, the ability of BN (as an atom sensor) to adsorb toxic metals, metalloids, and nonmetals is ordered as: Cd > Zn > Fe > Cr > Mn ≈ W. This article suggests that elements absorbed by BN could be used to develop and improve the optoelectronic properties of BN, helping to create photoelectric devices for soil cleaning.
The research on semiconductor electrocatalysts has developed into an active field of study in the past decade. By constructing heterojunctions, one may efficiently overcome the limitations of semiconductors’ broad band gaps and low conductivity. This work uses a single-step hydrothermal approach to load nitrogen-doped carbon quantum dots onto TiO2 nanoparticles, resulting in an excellent N−CQDs/TiO2 catalyst with an Ohmic contact effect for better NORR electrocatalytic performance under ambient circumstances. The ammonia production rate is 4242.24 μg·h−1·mg−1 at an applied potential of −0.90 V vs. RHE (in a 0.10 M K2SO4 electrolyte), and the Faradaic efficiency is 88.02%. When compared to the unmodified TiO2 catalytic performance, the ammonia generation rate doubles, and the Faradaic efficiency increases by 42.90%. A detailed investigation of the microstructure, charge transfer, NO adsorption, and reaction pathways of N−CQDs/TiO2 was performed using density functional theory (DFT) computations. According to the theoretical results, nitrogen doping creates an uneven charge distribution on carbon quantum dots, enhancing NO adsorption by N−CQDs. The Ohmic contact between N−CQDs and TiO2 facilitates charge transfer. The ICOHP value is more negative during NO adsorption on N-doped carbon quantum dots, decreasing the N=O interaction and boosting the NORR, according to crystal orbital Hamilton population (COHP) research. We have established the excellent performance and catalytic mechanism of the N−CQDs/TiO2 catalyst based on these discoveries, giving strong theoretical and experimental evidence for the creation of effective catalysts for nitrogen oxide reduction processes.
Linde Type A (LTA) zeolite was synthesised from purified Angren kaolin (Uzbekistan) by a metakaolin route. Raw kaolin was beneficiated by dispersion–decantation to reduce iron, calcined at 700 °C, and crystallised in NaOH solution at 100 °C. Products were characterised by powder X-ray diffraction (PXRD), X-ray fluorescence (XRF), Raman spectroscopy, N2 physisorption and thermal analysis (TGA/DTA). PXRD confirmed crystalline LTA as the major phase (cubic lattice parameter a = 24.68 ± 0.02 Å), with residual quartz from the precursor. XRF gave a near-ideal bulk composition (Si/Al = 1.07, Na/Al = 0.98), confirming sodium incorporation, and Raman corroborated minor quartz and anatase impurities. The very low N2 uptake at −196 °C reflects the restricted access of the 4 Å LTA windows rather than an absence of microporosity. Thermogravimetric analysis showed a ~13 wt% loss of zeolitic water below 300 °C, consistent with substantial hydration of the LTA framework. Locally sourced Angren kaolin can thus be converted into crystalline LTA, establishing a viable regional feedstock for a framework whose potential for molecular-sieve and ion-exchange applications remains to be evaluated by dedicated adsorption measurements.
Developing adsorbents with rapid kinetics and high adsorption capacity is essential for efficient CO2 capture. Herein, oxygen-rich porous carbons were synthesized from phenolic resin through K2CO3 activation. By systematically varying the activation temperature and K2CO3/precursor ratio, the evolution of pore structure and its influence on CO2 adsorption behavior were comprehensively investigated. The reaction between K2CO3 and the carbon matrix generated abundant micropores while preserving oxygen-containing surface functionalities, leading to enhanced adsorption affinity toward CO2 molecules. The optimized carbon exhibited a high specific surface area of 1065 m2 g−1 and a narrow micropore volume of 0.54 cm3g−1, delivering equilibrium CO2 uptake capacities of 5.48 and 3.92 mmol g−1 at 0 and 25 °C under 1 bar, respectively. In-depth analysis revealed that narrow microporosity played a more dominant role than total surface area in determining adsorption performance. Moreover, the optimized adsorbent showed a CO2/N2 selectivity of 15; rapid adsorption kinetics, with 90% of equilibrium capacity achieved within 4.5 min; and a dynamic CO2 capture capacity of 0.91 mmol g−1. The moderate isosteric heat of adsorption (20–36 kJ mol−1) and excellent cyclic stability further confirmed the physisorption-dominated nature of the process. This work highlights the synergistic role of ultramicropore engineering and oxygen-containing surface functionalities in designing efficient porous carbon adsorbents for carbon capture.
The underexplored Passerini–Smiles reaction (PSR), a variant of the 3-component Passerini reaction (3CPR), was successfully employed to create a tailored library of phenoxy-indoline carboxamide derivatives based on a fragment-based hybrid drug design strategy. Under mild conditions, inexpensive and commercially available isatin was utilized as a privileged carbonyl core, combined with electron-deficient phenols to establish a highly functionalized framework. Post-Passerini–Smiles transformations leveraged this strategic layout to provide a step-economical route to a complementary library of three-dimensional spirooxindole hybrids derived from the PS adducts. This study reinforces the relevance of combining structural hybridization with multicomponent reaction strategies in the discovery of potential anticancer active pharmaceutical ingredients (APIs). Both libraries were evaluated against six human solid-tumor cell lines, including non-small cell lung carcinoma, cervical and colon adenocarcinoma, and breast and pancreatic cancers. The most active compound 4gaa exhibited GI50 values below 10 μM for most of the tested cancer cell lines.
The structure, relative stability, spin-state preference, and preliminary oxygen-release behavior of small nickel–oxygen clusters, (NiO2)n (n = 1–4), were investigated using density functional theory at the M06-2X/def2-TZVP level of theory. Several initial topologies and spin multiplicities were explored to distinguish between dissociated Ni···O2 solutions, bonded dioxo-like arrangements, and side-on metal–dioxygen motifs. For the monomer, the lowest-energy solution of the fully explored set corresponds to a non-bonded Ni···O2 arrangement; however, when the analysis is restricted to chemically bonded NiO2 minima, the linear high-spin O–Ni–O structure is the most stable configuration. The side-on η2-O2 motif was found as a higher-energy bonded minimum, retaining an elongated O–O bond and therefore representing an activated dioxygen-like species. ELF and LOL analyses were used as complementary localization descriptors to distinguish between the electronically separated oxo-like domains of the linear structure and the more coupled localization pattern of the side-on dioxygen adduct. Aggregation from n = 2 to n = 4 suggests a transition from compact bridged motifs to more open Ni–O frameworks. However, the size-dependent trend is discussed only within the explicitly explored conformational space. Preliminary analysis of O2 release from the tetramer indicates that oxygen evolution is not a simple dissociation event but involves substantial structural reorganization. Overall, the results support the view that small (NiO2)n clusters may behave as metastable oxygen-rich intermediates, while also highlighting the strong sensitivity of their energetic ordering to spin state, topology, and structural relaxation.
CXCL8, a pro-inflammatory chemokine, which can be induced by TNF-alpha or IL-1, is responsible for the recruitment and activation of neutrophils. Chemokines interact with glycosaminoglycans on endothelial cells and are thus protected from degradation and sequestration, holding them in an optimal position for recruiting immune cells. Inhibiting the interaction of chemokines with their glycosaminoglycan co-receptors represents an attractive approach for the treatment of chemokine-mediated diseases. Two polyketide-pyrone compounds, PA501 and PA502 were synthesized, which bind to CXCL8 with affinities higher than the natural glycosaminoglycan ligand heparan sulfate, and in a similar range as heparin. Significant structural changes were induced in the chemokine by interacting with the two compounds, as expressed in fluorescence and far-UV CD experiments. In filter binding assays, both compounds were found to displace heparan sulfate efficiently from CXCL8, with PA501 displaying the highest competition efficacy. Using a C-terminally truncated form of the chemokine, CXCL81-58, which lacks the main glycosaminoglycan-binding alpha-helical domain, the two compounds are suggested to use-to a varying degree-different binding sites on the protein, which have also been proposed for the natural heparan sulfate ligand. In a transmigration assay, PA501 and PA502 exhibited dose-dependent modulation of CXCL8-induced neutrophil mobilization and migration. The compounds PA501 and PA502 may thus be regarded as early novel lead compounds in the quest for anti-inflammatory, chemokine-targeting drugs.
Photocycloaddition reactions provide an efficient strategy for converting alkenes into structurally complex and high-value molecules that are often difficult to access under conventional thermal conditions. Herein, two readily accessible triarylamine-based imine molecular cages possessing distinct cavity environments were investigated as supramolecular photocatalysts for reactions of pyridinium-masked enol (PME) substrates with unactivated alkenes. Spectroscopic studies are consistent with the formation of electron donor-acceptor (EDA) interactions between the electron-rich cage frameworks and electron-deficient PME substrates. Upon blue-light irradiation (450 nm), these charge-transfer assemblies undergo photoinduced activation, likely involving single-electron transfer, N-O bond cleavage, and subsequent radical generation. The resulting radical intermediates participate in formal [4 + 2] cycloaddition reactions to afford tetralone derivatives under metal-free conditions. Comparative studies revealed that the two cages produce distinct product distributions and selectivities, suggesting that subtle variations in cage architecture and confined supramolecular environments influence the fate of reactive radical intermediates and the balance between productive cyclization and competing side pathways. While the detailed mechanistic origin of these effects remains unresolved, this work demonstrates the potential of covalent organic cages as structurally tunable platforms for modulating EDA-mediated photochemical reactivity and radical selectivity.
As key therapeutic targets for symptomatic treatment of Alzheimer’s disease (AD) according to the cholinergic hypothesis, acetylcholinesterase (AChE; EC 3.1.1.7) and butyrylcholinesterase (BChE; EC 3.1.1.8) have been the subject of numerous studies over decades, leading to large collections of different ligands with corresponding AChE and BChE activity. This vast amount of data provides an ideal basis for the implementation of different machine learning (ML) and deep learning (DL) tools in different steps of the drug discovery process. Mainly applied to identify potential strong inhibitors of AChE and to a lesser extent BChE, many quantitative structure–activity relationship (QSAR) models and other predictive tools have been constructed utilizing different ML algorithms and DL techniques with various success depending on the input data and specific context. Here, we provide an extensive overview of such cases reported in the literature in recent years.
Several bioactive compounds, including phenolic and flavonoid substances, have been identified in the aqueous leaf extract of Schinus terebinthifolius (ALE). These compounds are active ingredients in green nanoparticle biosynthesis. Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), zeta potential analysis, and FTIR spectral analysis were used to characterize copper oxide nanoparticles (CuNPs) and silver nanoparticles (AgNPs). According to TEM results, AgNPs exhibited somewhat larger diameters (12 +/- 4 nm), were spherical with significant aggregation, and displayed a fairly uniform distribution, while CuNPs were primarily quasi-spherical with a narrow size range of about 4-5 nm. CuNPs showed a much more negative zeta potential value of -25.8 mV, indicating good to high colloidal stability, whereas AgNPs had a zeta potential of -15.5 mV, suggesting moderate stability. The main compounds included chlorogenic acid (10,375.28 & micro;g/g), gallic acid (7015.59 & micro;g/g extract), ellagic acid (1571.29 & micro;g/g extract), and rutin (1485 & micro;g/g extract). The antifungal activity of CuNPs and AgNPs was tested at concentrations of 6, 12, 25, 50, and 75 mu g/mL on Quercus rubra wood against Fusarium circinatum and Pythium tardicrescens. The greatest inhibition of F. circinatum growth was observed with CuNPs and AgNPs at 75 & micro;g/mL, showing fungal inhibition percentages (FIPs) of 61.48 and 60.74%, respectively. CuNPs and AgNPs at 75 & micro;g/mL exhibited moderate activity against P. tardicrescens, with FIPs of 21.48% and 15.92%, respectively. The MICs for AgNPs and CuNPs were 1.5 and 85 & micro;g/mL with F. circinatum and P. tardicrescens, respectively. Overall, CuNPs and AgNPs demonstrated potential antifungal activity against F. circinatum but moderate activity against P. tardicrescens compared to the control. This ALE from S. terebinthifolius is rich in flavonoids and phenolic compounds, including gallic acid, chlorogenic acid, rutin, ellagic acid, and p-coumaric acid, as identified by HPLC analysis. These biomolecules act as both capping agents, which stabilize the nanoparticles, and reducing agents. Using S. terebinthifolius ALE's rich phytochemical profile as a reducing and stabilizing agent provides an environmentally friendly method for the green synthesis of CuNPs and AgNPs.
Understanding the atomic-scale mechanisms of coal pyrolysis is essential for efficient coal utilization and carbon-neutral energy strategies, yet conventional computational approaches often struggle to balance between the high accuracy of quantum-chemical calculations and the efficiency of reactive force fields. To overcome this limitation, we proposed a multiscale computational framework integrating high-throughput density functional theory (DFT) calculations, ReaxFF-based configuration sampling, YARP reaction enumeration, and DPA3-based machine learning potentials (MLPs). Two coal-specific MLPs, DPA3-coal and DPA3-coal@dftb, were constructed and systematically benchmarked on both small molecular systems and larger C20-30 coal fragments extracted from MD simulations. DPA3-coal@dftb model demonstrated significantly improved accuracy over ReaxFF in predicting energies and atomic forces while maintaining good transferability. To balance computational efficiency and accuracy in large-scale simulations, the DPA3-coal model was employed to perform accelerated reactive molecular dynamics simulations of a Solomon-type bituminous coal molecule from 1600 to 2600 K. The simulations revealed temperature-dependent evolution of coke, tar, and gas products, including secondary condensation and deep-cracking processes at elevated temperatures. Higher-level DFT calculations further confirmed the thermodynamic consistency of key reaction pathways involving radical formation, H-transfer, recombination, and CO generation, indicating that coal-specific MLPs provide an effective atomistic tool for investigating mechanistic trends in coal pyrolysis.
Apple juice is one of the world's most widely consumed fruit juices and is therefore a common target for economically motivated adulteration (EMA). Such adulteration may involve dilution with water, substitution with other juices, or the addition of exogenous sugars, each requiring robust analytical methods for detection. In this study, we present an improved analytical method for identifying exogenous C4-type sugars in apple juice which utilizes the naturally occurring sorbitol as an endogenous isotopic reference marker. The method uses liquid chromatography coupled to isotope ratio mass spectrometry (LC-IRMS) to determine the delta 13C values of the major endogenous sugars in apple juice. The study shows that the delta 13C value of sorbitol can be measured in the same analytical run as the other major sugar components and remains unaffected by the addition of exogenous C4-type sugars to the apple juice. This method offers significant advantages over existing approaches, notably by eliminating the need for extensive sample preparation and multiple analytical methods thereby improving both analytical throughput and ease of use.
Cholinesterases (ChEs) are irreversibly inhibited by organophosphorous compounds (OP). Then, OP-inhibited ChEs undergo a reaction that progressively decreases reactivatability. This process called “aging” results from dealkylation of the adduct. Aged ChEs are resistant to antidotal oximes. Structural and conformational changes in the aged phosphylated ChE active site pocket impair enzyme reactivatability. Thus, reactivation of aged ChEs was a challenge for more than 70 years. However, it was postulated that realkylation of aged adducts could lead to reactivation of enzymes. This hypothesis was confirmed in 2018 when a new generation of reactivators, electrophilic quinone methide precursors (QMPs), capable of resuscitating or resurrecting aged ChEs were synthesized. The QMP-mediated resurrection process of ChEs by these first “resurrectors” is still very slow. Thus, substantial optimization in the chemical design of new drugs and drug-targeted delivery are needed before the resurrection approach can be translated into clinically viable therapies. However, despite limitations, the first achievements resolving the non-reactivatability issue of OP-aged cholinesterases and successful administration of these new reactivators can be regarded as a major step forward in improving the therapy of OP poisoning.
We report the synthesis, characterisation and electronic modulation of three novel fused polyheterocyclic ligands-naphtho[1,2-b]furan-4,5-dione (1), furo[3 ',2 ':3,4]naphtho[1,2-d]imidazole (2), and benzo[a]furo[2,3-c]phenazine (3)-and their Cu(II), Zn(II) and Fe(II/III) complexes. Compound (1) was isolated at 96.5% yield using fulvic acid as a green organocatalyst. 57Fe M & ouml;ssbauer spectroscopy identified two high-spin Fe(III) environments in a 37:63 ratio (delta = 0.377 mm s-1; Delta = 0.62 and 1.01 mm s-1), with no evidence of magnetically ordered oxide phases. Six enantiomeric metal malate salts were synthesised at 86-93% yield for spectrophotometric titrations. The key finding is a striking Cu(II)-specific enantioselective molecular recognition: (3) binds (S)-(-)-malate Cu(II) with log K = 9.02, a factor of 2.5 & times; higher than the (R)-(+)-malate complex (log K = 8.62), while Fe(II) and Zn(II) show no enantioselectivity. These results establish chiral counter-ion engineering combined with pi-conjugated polyheterocyclic scaffolds as a powerful strategy for chiroptical sensing and asymmetric catalysis.
Access to clean and safe drinking water for all remains a global challenge, mainly for rural populations and areas affected by natural disasters or humanitarian crises. The traditional water quality treatment technologies can work well in laboratory or controlled settings, but they are usually applied under conditions unavailable in these types of conditions. Traditional water quality treatment methods are limited by established infrastructure, expensive operating costs, energy requirements, and the ability to perform in-field water treatment. To improve the barriers of traditional water quality treatment technologies, recently developed scientific discoveries of nanozymes, a new class of nanomaterials with enzyme-like catalytic activity, have shown the ability to decentralise water purification. Nanozymes provide a mechanism for water treatment that does not require the infrastructure or the cost of traditional water quality treatment methods. Also, nanozymes possess extremely high catalytic activity, chemical stability, are inexpensive, and are suitable for a variety of contaminants. This review gives a systematic overview of the development of suitable nanozyme-based portable water purification systems. It shows their catalytic mechanisms, the class of nanozymes used, and the design characteristics related to their working use, also highlighting the developments that consider the specific needs of rural contexts, provide rapid responses to disaster areas, and offer drinking water with reliable, simple, and sustainable apparatus.
In this work, the effect of chitosan concentration in chitosan/nickel composite coatings on their morphology and electrocatalytic activity in hydrogen evolution reaction (HER) was investigated. A series of Chitosan/Ni coatings with chitosan content from 0 to 0.7 wt.% was obtained by nickel electrodeposition onto a preformed biopolymer matrix, enabling targeted control of the roughness and specific surface area of the nickel layers. Morphology and roughness parameters were studied using atomic force microscopy and confocal microscopy. Electrochemical activity in the HER was examined by linear sweep voltammetry. Among the studied electrocatalysts, the Chitosan(0.6)/Ni system showed the best HER efficiency, with an overpotential of -200 mV at a current density of 10 mA/cm2. Electrochemical impedance spectroscopy was used to determine the real surface area of the coatings. The Chitosan(0.6)/Ni sample exhibited the largest surface area, explaining its high HER activity. The obtained data revealed a correlation between chitosan concentration, composite morphology, and electrochemical activity, and allowed determination of the optimal composite composition. The results demonstrate the potential of chitosan as an effective structural modifier of nickel coatings and open up possibilities for the targeted design of composite materials with tailored electrochemical properties.
