Research Articles (Chemistry)

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Advancing functionalized track-etched membranes: composite and hybrid materials through the JINR–South Africa partnership
(E.A. Buketov Karaganda University Publish house, 2025) Rossouw, Arnoux; Petrik, Leslie Felicia; Nechaev, Alexander Nikolaevich; Apel, Pavel Yurievich
Track-etched polymer membranes (TeMs) are precision porous materials widely applied in water purification, sensing, and catalysis. However, their practical use is limited by hydrophobicity, fouling, and lack of functional activity. The purpose of this review is to synthesize the outcomes of the long-standing collaboration between South African institutions and the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research in Dubna, Russia (FLNR, JINR), highlighting their contribution to overcoming these chal-lenges. The objective is to present a focused survey of advances in TeMs functionalization, contextualized within global progress, and to assess their implications for applied membrane science. The methodology involved a structured literature survey (2007–2025) across Scopus, Web of Science, and Google Scholar, combined with critical evaluation of collaborative outputs. Emphasis was placed on peer-reviewed studies of metal sputtering, chemical grafting, and electrospun nanofiber composites. Results indicate that these approaches improve TeMs performance by enhancing hydrophilicity, mechanical stability, and catalytic or sensing func-tionality. Case studies include Ti/TiO2 coatings for self-cleaning membranes, silver/gold nanoparticle-modified TeMs for surface-enhanced Raman spectroscopy, and nanofiber/TeMs hybrids for pollutant adsorp-tion. In conclusion, the JINR — South Africa partnership demonstrates how targeted international collaboration can deliver impactful technologies. Future research should prioritize stimuli-responsive “smart” mem-branes, MOF-integrated hybrids, and roll-to-roll scale-up for industrial deployment.
Smart Worksheets to probe and support scientific numeracy proficiency of first-year chemistry students
(Academy of Science of South Africa, 2025) Sewry, Joyce; Coyte, Emily; Williams, Leanne; Barker, Aidan; Suryawanshi, Shubham; Shallcross, Dudley E; Davies-Coleman, Michael T
The transition to university-level chemistry often reveals numeracy skills gaps that can hinder student confidence and academic success. Online learning tools can help characterise and address these gaps. This study introduces a Scientific Numeracy Smart Worksheet (SNSW) resource to characterise and address the numeracy-based strengths and weaknesses of a large cohort of first-year chemistry students at a South African university. We also investigated student usage and perceptions of this educational resource. The SNSW integrates core mathematical concepts with subject-specific contexts, features high levels of feedback, value randomisation, and an auto-solve feature for struggling students. It was offered as formative support for chemistry students near the start of their university journey. Usage and performance analytics from consenting students were used to study overall and section-level SNSW performance, while an anonymous questionnaire explored student perceptions. Students performed well at ‘Displaying numbers’ (85%) and ‘Rearranging and solving equations’ (84%). The lowest scoring sections were ‘Graphs’ (64%) and ‘Averages and spread of data’ (72%). ‘Scientific units’ showed the highest auto-solve percentage. Students who repeated the SNSW scored significantly higher and used the auto-solve feature significantly less on the second attempt (both p < 0.001) and scored higher in quantitative components of their end-of-module assessment, but not significantly so (p = 0.082). The questionnaire indicated high student rating for the SNSW (8.2/10), with most students finding it helpful and at the appropriate level. Providing supportive and diagnostic resources can help students develop numeracy skills and identify areas for personal improvement. Instantaneous data, generated from each student engagement with SNSW, can assist staff to develop educational strategies to target specific transitional skill deficiencies. Significance: Learners at secondary schools and university students alike struggle with basic numeracy concepts, such as ratios and proportions, graphs and SI units. First year chemistry curricula are full, with little time spent on revising content from school. The SNSW is a means of solving this problem. Students work through the worksheets at their own pace and receive immediate feedback. This research highlights both the gaps in students’ numeracy skills, and a corrective intervention by first-year chemistry lecturers.
Enhanced activity and durability of high-temperature proton exchange membrane fuel cells enabled by ionic liquid-modified Pt-Ni nanochains
(Elsevier Ltd, 2025) Liu, Qingqing; Liu, Huiyuan; Zhang, Weiqi; Xu, Qian; Khotseng, Lindiwe; Pasupathi, Sivakumar; Su, Huaneng
The performance of high-temperature proton exchange membrane fuel cells (HT-PEMFCs) is severely limited by the poisoning effect and low oxygen solubility of the phosphoric acid (PA) electrolyte. To address this, we report an innovative catalyst architecture consisting of one-dimensional hollow PtNi nanochains coated with a functional ionic liquid (IL), termed PtNi@IL/C. This design creates a multifunctional interface that demonstrates exceptional PA tolerance, achieving an oxygen reduction reaction (ORR) half-wave potential of 0.840 V in a PA-containing electrolyte, which is 90 mV higher than commercial Pt/C.
Derivatives of pyrazole-based compounds as prospective cancer agents
(American Chemical Society, 2025) Ramoba, Lesetja V; Nzondomyo, Wakopo J; Serala, Karabo; Macharia, Lucy W; Biswas, Supratim; Prince, Sharon; Malan, Frederick P; Alexander, Orbett T; Manicum, Amanda-Lee E
Five pyrazole-based compounds, 3,5-dimethyl-1H-pyrazole, L1; 3,5-diphenyl-1H-pyrazole, L2; 3-(trifluoromethyl)-5-phenyl-1H-pyrazole, L3; 3- (trifluoromethyl)-5-methyl-1H-pyrazole, L4; and 3,5-ditert-butyl-1H-pyrazole, L5 were synthesized from a typical condensation reaction of β-diketone derivatives with hydrazine hydrate reagent and characterized using various spectroscopic techniques such as FT-IR, UV−vis, 1H and 13C NMR, and LC−MS spectroscopy. L1 was further analyzed by single-crystal X-ray diffraction, and the N1−N1′ bond distance was found to be 1.361(3) Å and correlated well with other pyrazole-based compounds. The short-term cytotoxicity of 10 μM pyrazole compounds (L1−L5) was evaluated against pancreatic (CFPAC-1 and PANC-1), breast (MDA-MB-231 and MCF-7), and cervical (CaSki and HeLa) cancer cell lines using the MTT cell viability assay. Cisplatin and gemcitabine were included as positive control drugs followed by the determination of the half-maximal effective concentrations of prospective compounds. L2 and L3, respectively, displayed moderate cytotoxicity against CFPAC-1 (61.7 ± 4.9 μM) and MCF-7 (81.48 ± 0.89 μM) cell lines.
Advances on electrochemiluminescent biosensors for TB biomarkers
(American Chemical Society, 2025) Cox, Meleskow; January, Jaymi; Mokwebo, Kefilwe Vanessa; Yussuf, Sodiq T; Sanga, Nelia Abraham; Leve, Zandile Dennis; Douman, Samantha Fiona; Iwuoha, Emmanuel Iheanyichukwu
Tuberculosis (TB) is a highly contagious bacterial infection that remains a leading cause of death and persistent threat to global health. The spread of TB is exacerbated by the major limitations of conventional diagnostic approaches, such as complex technicalities, high cost, and low sensitivity. To address these challenges, recent research has focused on using electrochemiluminescence (ECL) as an alternative detection strategy coupled to biosensors. ECL biosensors leverage electrochemically generated chemiluminescence, converting electrical energy to light, as a novel transduction mechanism for TB biosensors. This unique approach offers several advantages, namely, wide linear dynamic ranges, improved device sensitivities, and prompt response times for sensitive early detection. This Review offers a comprehensive overview of advancements in ECL biosensor configurations, including detection and amplification strategies, substrates, and the development of luminophores and coreactants tailored for TB biomarker detection. The focus is on ECL biosensor designs, including biorecognition elements like immunosensors, DNA sensors, and aptasensors, along with various immobilization strategies tailored to target specific TB biomarkers. A comprehensive discussion spans biomarker detection trends over the past decade, clinical relevance, sensitivity thresholds, and detection limits. Furthermore, widely recognized TB biomarkers commonly detected in commercial diagnostic tests are discussed alongside novel markers that, while not exclusive to TB, have demonstrated clinical importance. This Review aims to highlight the potential of ECL-based biosensors as an effective means to advance an early, reliable, and accessible TB detection approach.
Delamination of aluminium current collectors from spent ithium-Ion Battery Cathodes Using Room-Temperature Organic Acid-Assisted Ultrasonication
(Multidisciplinary Digital Publishing Institute (MDPI), 2026) Tawonezvi, Tendai; Sinto, Anele; Qhina, Mihle N.
The strong adhesion between cathode materials and aluminium (Al) foil substrates presents a significant challenge in the recycling of spent lithium-ion batteries (LiBs). Conventionally, high temperatures and high concentrations of costly organic solvents such as N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAC), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) are used to enhance ultrasonication-based delamination. In this study, a novel, eco-efficient approach was demonstrated for delaminating cathode materials from Al foil using a low-concentration organic citric-acid-assisted low-power ultrasonic treatment coupled with a gentle, low-power-per-volume mechanical mixing system at room temperature. The separation mechanism was attributed to the structure disruption, possibly swelling, of the polyvinylidene fluoride (PVDF) binder using low-concentration citric acid and the cavitation effects induced by ultrasound. Key parameters influencing the delamination efficiency included the solvent type, temperature, ultrasonic power, and treatment duration. Under optimised conditions, citric acid was used as the sonication reagent, with a process temperature of 20 °C, 60 W ultrasonic power, and 80 min of ultrasonication; a delamination efficiency of approximately 92% was achieved. The recovered cathode materials exhibited low agglomeration, favouring subsequent leaching processes. This work proposes an environmentally friendly and effective method for cathode and Al foil recovery from spent LiBs, integrating manual dismantling, ultrasonic treatment, and material separation.
Telluride quantum dot-amplified immunosensor for interferon gamma – a TB antigen test biomarker
(Elsevier B.V, 2025) Mini, Sixolile; Januarie, Kaylin Cleo; Oranzie, Marlon; Cupido, Candice; Mokwebo, Kefilwe Vanessa; Feleni, Usisipho; Iwuoha, Emmanuel
Interferon-gamma (IFN-γ) is a cytokine (i.e. a microprotein involved in cell signaling and immunomodulation) which is known to be expressed in response to Mycobacterium tuberculosis (Mtb) infections. For this reason, IFN-γ has gained prominence as a diagnostic biomarker for TB antigen tests, such as Interferon-Gamma Release Assays (IGRAs). Recent research efforts have focused on improving the sensitivity of TB tests based on IFN-γ. In this study, a new and sensitive chalcogenide-based electrochemical IFN-γ immunosensor was developed. The chalcogenide is a 9.30 nm average diameter bimetallic copper zinc telluride (CuZnTe) quantum dot (QD) particles, which were stabilised by sequential triple-capping with thioglycolic acid (TGA), (3-mercaptopropyl)trimethoxysilane (MPS) and tetraethylorthosilicate (TEOS) (i.e. CuZnTe-TGA-MPS-TEOS QD). The morphologies of the quantum dots were determined by X-ray transmission electron microscopy (TEM) and small angle X-ray scattering spectroscopy (SAXS); while their structural characteristics were ascertained with Raman and X-ray diffraction (XRD) spectroscopic analyses. A gold disk electrode (AuE) surface was functionalized with CuZnTe-TGA-MPS-TEOS QD, anti-interferon-gamma antibody (Anti) and bovine serum albumin (BSA) to create a BSA/Anti/CuZnTe-TGA-MPS-TEOS QD/AuE amperometric immunosensor bioelectrode. The immunosensor exhibited a linear detection range (LDR) value of 2–20 pg/mL IFN-γ, a limit of detection (LOD) value of 0.82 pg/mL IFN-γ and was highly sensitive in human serum samples with recovery rates of 97–99 %.
Biobased biodegradable polybutylene succinate polymers and composites: synthesis, structure properties and applications—a review
(Tech Science Press, 2025) Makgwane, Peter Ramashadi; Muniyasamy, Sudhaka; Hlekelele, Lerato; Swanepoel, Andri; Sypu, Venkata Satyanarayana; Mdlalose, Lindani; Naidoo, Saloshnee; Cele, Zamani; Maity, Arjun; Balogun, Mohammed; Botlhoko, Orebotse Joseph
The materialization of polybutylene succinate (PBS) belongs to the family of polyesters which are degradable and biodegradable, their biodegradability properties have attracted enormous interest for product development towards different polymer-based applications. Besides its biodegradability, PBS can be derived from petroleum and biobased monomers. At the same time, the latter is the driving factor for its growing interest in bioplastics for fully green and sustainable biobased-derived polymer products. The processes and techniques presented herein, are based on the production of biobased succinic acid monomer to PBS. However, the counterpart biobased monomer 1,4-butanediol (1,4-BDO) production has not been commercially demonstrated. This review discusses the progress in state-of-the-art developments in the synthesis strategies of PBS, its copolymers, and composites with the view to improve molecular weight, thermal, and mechanical properties. It further analyzes the different strategies to synthesize modified PBS polymer composites from organic and inorganic nanofillers to enhance their chemical, thermal, stability and mechanical structural properties. Importantly, the review highlights the progress in the applications of PBS copolymers and composites with tailored structure-designed properties for specific sectors such as packaging films, biomedical and drug release, fire retardants, and agricultural products. The structure-functional performance characteristics of these developments in the PBS, copolymers, and composites are highlighted to provide baseline insights for future developments in engineering the specific applications, and structural interface PBS composites with enhanced structure-functional performance properties.
POM-activated gCN intermediate as a new composite precursor for organic–inorganic materials: introducing a new composite as a starting material toward graphitic carbon nitride-based photocatalysts
(Springer, 2026) Djoko, Simon Yves; Schwarze, Michael; Brüggemann, Daniel Christian; Isbrücker, Philipp Harry; Tchegnitegni, Billy Toussie; Thomas, Arne Faunce; Arellano-García, Harvey; SchomÃ¤cker, Reinhard
Polyoxometalate (POM)-modified graphitic carbon nitride (gCN) has emerged as a promising candidate for heterogeneous catalytic reactions. The introduction of POM-modified graphitic carbon nitride as a novel ligand/binder composite represents a significant stride in material science, particularly in synthesizing organic–inorganic hybrid materials. When combined with phosphomolybdic acid (PMA), gCN can form an activated composite intermediate (gCN/PMA) exhibiting multifunctional properties suitable for various applications in materials science and catalysis. This study advocates for a gCN/PMA composite as a fresh starting reagent for chemical synthetic routes, leading to the creation of structured materials. This groundbreaking composite material utilizes the special properties of POMs and gCN, creating a versatile platform for the formation of derived metal semiconductor materials. Chemical synthetic routes, including the gCN/PMA composite, have been proposed for fabricating 2D and 3D porous doped gCN and nanoparticle@MOF hybrid materials. By harnessing the complementary properties of PMA and gCN, this composite material offers enhanced functionality and performance compared to its individual components. The potential for continued research and development in this area is immense, with the promise of significant and promising breakthroughs that will further solidify the role of these composites in advancing modern technology and sustainable solutions. This work opens up a world of possibilities for designing advanced materials with tailored properties for various applications, including photocatalysis, energy storage, and environmental remediation.
Controlling the optoelectronics of poly(3-hexylthiophene-2,5-diyl) dendritic star copolymers on a polypropylenimine core as donor materials for organic solar cells
(American Chemical Society, 2026) Ramoroka, Morongwa Emmanuel; Cox, Meleskow; Feleni, Gwibakazi Abena; Mabuza, Luyanda S.; Isaacs, Beshara Sandra; Mohamed, Rhiyaad; Xia, Ruidong; Peng, Xinwen; Iwuoha, Emmanuel Iheanyichukwu
The development of novel copolymers as donor materials for organic solar cells and optimization of their properties are particularly interesting, but remain challenging. This research report presents the first study on the effect of copolymerization time on the synthesis of the copolymer poly(propyleneimine) tetra(N-methyl-2-pyrrolylmethylene amine)-co-poly(3-hexylthiophene-2,5-diyl) (P3HT-PP) using the chemical oxidative polymerization method. Through thorough experiments and copolymer characterization, a preferred copolymerization time is proposed, ensuring that the properties of the synthesized copolymers are significantly improved. The structural, optical, morphological, thermal, and rheological properties of synthesized copolymers at different copolymerization times (24, 48, and 72 h) were investigated by using nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis, Raman spectroscopy, small-angle X-ray scattering, rheometry, X-ray diffraction, ultraviolet–visible spectroscopy, and photoluminescence spectroscopy. Additionally, the effects of copolymerization time on the LUMO/HOMO energy levels and charge-transfer processes were examined by using cyclic voltammetry and electrochemical impedance spectroscopy, respectively. It was revealed that the copolymer synthesized for 24 h (P3HT-PP24) has the best properties suitable for organic solar cell applications as a donor material as compared to copolymers synthesized for 48 h (P3HT-PP48) and 72 h (P3HT-PP72). The P3HT-PP24-based organic solar cell exhibited the best photovoltaic performance due to reduced photogenerated charge recombination and more efficient exciton separation. © 2026 The Authors. Published by American Chemical Society.
Adsorption of rees from aqueous solutions using modified polystyrene- di (2-ethylhexyl) phosphoric acid electrospun nanofibers
(Elsevier B.V., 2026) Mukaba Jean-Luc; Massima Mouele, Emile Salomon; Ameh, Alechine Emmanuel; Eze, Chucks Paul; Petrik, Leslie Felicia; Tshentu, Zenixole R.
The recovery and separation of rare earth elements (REEs) is an emerging area of the current research due to their applications in modern technology and because both accessible and cost-effective approaches are required. In this study, polystyrene (PS) grafted with di(2-ethylhexyl) phosphoric acid (D2EHPA) ligand was fabricated via the electrospinning technique. The electrospun PS/DEHPA nanofiber mats were characterised using various techniques such as HR-SEM, TGA, FTIR, XRD, BET and ICP-OES. The fabricated electrospun nanofiber materials were then used for the recovery of Nd and Sm metal ions from the aqueous solutions. The supreme sorption uptake of Nd3+ and Sm3+was ˃ 100 mg/g at pH 4.0, reached at an equilibrium time of 70 min with the modified PS/DEHPA nanofiber mats. The recovery of Nd3+ and Sm3+was best described by the Langmuir isotherm and followed a pseudo second-order kinetic model. Thermodynamic data, ΔG°, Δ H° and ΔS° suggest that Nd3+ sorption onto PS/DEHPA was spontaneous and endothermic. The coordination of PS with the D2EHPA ligand occurred via hydrogen bonding while the binding of PS/DEHPA to the metal ion was likely bonded by ionic, covalent or electrostatic interactions. The reusability investigation indicates that the synthesized PS/DEHPA nanofiber mats can withstand up to four successive cycles, and the adsorption and desorption performances were over 60 %. Nd3+ sorption in the presence of interfering Ni2+ and Co2+ metals was 96.82 mg g−1(0.671 mmol g−1), closer to 101.46 mg g−1(0.703 mmolg−1) obtained in a single metal ion solution suggesting a good selectivity of PS/DEHPA fibres towards REEs (Nd3+).
A self-powered triboelectric nanogenerator for energy collection based on polydimethylsiloxane/dopamine/Ag nanowires porous materials formed by manganese carbonate
(Elsevier B.V, 2025) Guan, Yanfang; Yang, Wei; Yang, Lin; Wang, Han; Xi, Zhengyang; Kang, Yuliang; Zhao, Zaoran; Zhu, Changwei; Petrik, Leslie Felicia; Shen, Minggang; Wan, Zhenshuai; Yue, Longwang; Li, Peng
Triboelectric nanogenerators (TENG) possess significant potential and offer a wide range of applications to harness low frequency micro energy from the environment. However, TENG faces challenges related to the weak tightness of bipolar materials, low charge density, and so on. In this paper, we present a novel TENG, utilizing a 0.1 mm thick nylon film as the positive electrode material and a porous material composed of PDMS/MnCO3 modified by dopamine (PDA) and Ag NWs as the negative electrode material. The sacrificial material, MnCO3, was employed to create dense internal pores within the substrate material, PDMS, resulting in a highly porous PDMS (PPDMS) substrate. The triboelectric layer of TENG resembles a sponge with 20–40 μm pores, filling the PPDMS with high dielectric constant silver nanowires (Ag NWs) effectively enhances surface charge on the triboelectric material, leading to improved output performance. The modified TENG, based on PDMS/PDA/Ag NWs (PPA) achieves an 80 V open circuit voltage, 70.4 mW/m2 effective output power density, and sustains 10,000 contact separations without damage. Finally, energy collection devices for ocean-ball and human walking scenarios with the PPA/nylon-based TENG are designed and fabricated. The PPA/nylon-based TENG exhibits promising potential for collecting, converting, and storing clean energy.
Effects of morphological and physicochemical surface properties of track-etched membranes made from polyethylene terephthalate, polycarbonate and polyethylene naphthalate on protein adsorption
(Elsevier B.V, 2026) Serpionov, Genrikh V.; Molokanova, Ludmila G; Nikolskaya, Daria V; Drozhzhin, Nikita A; Vinogradov, Iliya I; Rossouw, Arnoux; Andreev, Evgeny V; Orelovich, Oleg L; Petrik, Leslie F; Nechaev, Alexander N
This study presents a comparative analysis of bovine serum albumin (BSA), hemoglobin, and lysozyme adsorption on track-etched membranes (TMs) based on polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polycarbonate (PC) with similar structural parameters. The specific surface area was 1.7, 1.9, and 1.3 m²·g⁻¹ for PEN, PET, and PC TMs, respectively. PEN and PET TMs were rougher (Sq ≈ 6.2–9.4 nm) and hydrophilic (contact angle ≈55°), whereas PC TMs were smoother (Sq ' 2.8 nm) and moderately hydrophobic (contact angle '80°). All membranes were negatively charged (zeta potential: –14.9 to –23.6 mV). No measurable BSA adsorption was observed using the spectrophotometric method. Hemoglobin adsorption followed PEN ' PET ' PC, with capacities of 7.9, 6.4, and 3.4 mg·g⁻¹ , respectively, all fitted by the Langmuir isotherm. Lysozyme adsorption was substantially higher on PEN (9.9 mg·g⁻¹) and PET (9.3 mg·g⁻¹) than on PC (2.3 mg·g⁻¹). Adsorption on PEN was best described by the Jovanović model, on PET by the Temkin isotherm, and on PC by the Langmuir model, indicating different adsorption behaviours. The novelty of this work lies in the multimethodological and multimodel approach that identifies surface roughness, protein molecular size and electrostatic interactions as key factors governing protein adsorption on TMs. Protein adsorption on PEN-based TMs is reported for the first time. This study shows that protein adsorption on TMs is relevant not only to fouling in filtration but also to biosensing and cell culture, providing a basis for rational selection of TM materials for biomedical and separation applications.
Macrophages bend long fibres with flexural rigidity lower than 3 mN·nm2 to avoid frustrated phagocytosis
(BioMed Central Ltd, 2026) Brossell, Dirk; Meyer-Plath, Asmus; Gräb, Oliver; Heunisch, Elisabeth; Kämpf, Kerstin; Haase, Andrea; Wiemann, Martin
Background: It is an established toxicological principle that the inhalation pathogenicity of respirable and biodurable fibres is caused by excessive fibre length as alveolar macrophages fail to uptake and remove such fibres. However, studies on carbon nanotubes showed that this principle needs revision, as thin, flexible variants showed reduced fibre-specific toxicity. One potential explanation is that the low flexural rigidity of thin fibres enables macrophages to bend and internalize even those that are long relative to the cell size. To evaluate this proposed “rigidity hypothesis,” the mechanisms governing the uptake of flexible long fibres that determine a critical threshold value for flexural rigidity require clarification. Methods: We exposed NR8383 rat alveolar macrophages to three silver nanowire variants differing in diameter and length. Time-lapse microscopy captured fibre uptake processes. Successful internalization of long fibres was found to require fibre bending during uptake. A mechanical model was developed by combining established cytoskeletal biophysics with the observed fibre deformation dynamics. As flexural rigidity describes fibre behaviour under load, our model estimated rigidity by reproducing the observed bent fibre shape. By defining limit cases for physically ‘weak’ and ‘strong’ NR8383 macrophages, i.e., assuming upper bounds on the forces generated by their cytoskeletal nanomachinery, our model enabled us to derive a range for the critical fibre rigidity threshold. Results and conclusion: A macrophage was observed bending an exceptionally long fibre (~ 140 μm) first into an arc and then a spiral for full internalization, initiated by a pseudopod extending along the fibre and buckling the internalized segment. Our model can reproduce such behaviour. It yielded a flexural rigidity of 20 mN·nm² for this fibre. Predicted critical rigidity limits for fibres that just fit into NR8383 macrophages range from 3 to 62 mN·nm².
Dual-facet modulation involving surface carboxyl functionalization and interlayer regulation by CQDs in g-C3N4 for enhanced xylose photooxidation
(Elsevier B.V., 2026) Iwuoha, Emmanuel
Photocatalytic oxidation of biomass-derived xylose to xylonic acid provides a sustainable route for producing high-value sugar acids under mild conditions. However, its practical application is often limited by poor selectivity caused by uncontrolled radical reactions promoting Csingle bondC bond cleavage and deep oxidation. Herein, we propose that bamboo-derived carbon precursors are employed to construct an in-plane heterojunction between conjugated carbon domains and graphitic carbon nitride (g-C3N4), in which bamboo-derived carbon quantum dots (CQDs) act as electron bridges to facilitate interlayer charge transport and thereby enhance surface-directed electron migration. This effect is evidenced by enhanced photocurrent responses, reduced charge-transfer resistance, prolonged carrier lifetimes, and increased electron delocalization. Meanwhile, carbonyl groups on the CQD surface promote the adsorption and activation of xylose at the reaction interface through an electron-withdrawing effect. Mechanistic investigations further identify superoxide (·O2−) and singlet oxygen (1O2) as the dominant reactive oxygen species responsible for selective xylose oxidation. Consequently, the optimized catalyst achieves an 84.4% yield of xylonic acid under visible-light irradiation with excellent stability. This work establishes reaction-demand-oriented charge-transport engineering as a key design principle for the selective photocatalytic upgrading of biomass-derived sugars.
Potential use of metal organic framework composites by recycling 4-nitrophenol in wastewater for electrocatalytic hydrogen production: A waste-to-profit approach
(Elsevier Ltd, 2026) Iwuoha, Emmanuel I; Maake, Tumisang J; Ramohlola, Kabelo E
Development of efficient and sustainable hydrogen evolution reaction (HER) electrocatalyst is crucial for advancing green hydrogen technology. Herein, a waste-to-profit strategy is proposed wherein metal–organic frameworks (Cu-BTC and Cu-BDC) are employed for the removal of 4-nitrophenol (4NP) from wastewater and use the resultant adsorbent–adsorbate composites (Cu-BTC4NP and Cu-BDC4NP) for HER. MOFs were synthesised hydrothermally, and their effective adsorption of 4NP was confirmed through equilibrium and kinetic studies, revealing high adsorption capacities exceeding 500 mg g−1. Linear sweep voltammetry (LSV) revealed that Cu-BDC required low overpotential of 133.99 mV to reach a current density of 10 mA cm−2 compared to the 4NP-loaded composites which exhibited higher overpotentials of 175.54 mV (Cu-BTC4NP) and 203.88 Mv (Cu-BDC4NP). This decline suggests that 4NP adsorption modifies the electronic environment of Cu active sites and may induce framework instability in aqueous media, where hydrolysis of metal–carboxylate bonds is a concern.
Potential use of metal organic framework composites by recycling 4-nitrophenol in wastewater for electrocatalytic hydrogen production: A waste-to-profit approach
(Elsevier Ltd, 2026) Iwuoha, Emmanuel I; Maake, Tumisang J; Ramohlola, Kabelo E
Development of efficient and sustainable hydrogen evolution reaction (HER) electrocatalyst is crucial for advancing green hydrogen technology. Herein, a waste-to-profit strategy is proposed wherein metal–organic frameworks (Cu-BTC and Cu-BDC) are employed for the removal of 4-nitrophenol (4NP) from wastewater and use the resultant adsorbent–adsorbate composites (Cu-BTC4NP and Cu-BDC4NP) for HER. MOFs were synthesised hydrothermally, and their effective adsorption of 4NP was confirmed through equilibrium and kinetic studies, revealing high adsorption capacities exceeding 500 mg g−1. Linear sweep voltammetry (LSV) revealed that Cu-BDC required low overpotential of 133.99 mV to reach a current density of 10 mA cm−2 compared to the 4NP-loaded composites which exhibited higher overpotentials of 175.54 mV (Cu-BTC4NP) and 203.88 Mv (Cu-BDC4NP). This decline suggests that 4NP adsorption modifies the electronic environment of Cu active sites and may induce framework instability in aqueous media, where hydrolysis of metal–carboxylate bonds is a concern.
Single-atom-anchored hierarchically nanopores hard carbon toward high-performance sodium storage
(Elsevier B.V., 2026) Iwuoha, Emmanuel; Wang, Qi; Zou, Ren
Hard carbon anodes for sodium-ion batteries (SIBs) face a critical challenge in simultaneously achieving high capacity and rapid reaction kinetics, particularly in the low-voltage plateau region, due to the ambiguous storage mechanism and sluggish ion transport. Herein, we demonstrate a one-step metal salt-catalyzed strategy that enables the concurrent construction of hierarchical nanopores and the immobilization of single-atom Zn-N4 sites within hard carbon derived from lignosulfonate biomass. The resulting material achieves a remarkable reversible capacity of 354 mAh/g at 0.02 A/g and outstanding rate capability (238 mAh/g at 3.0 A/g). In situ X-ray diffraction (XRD) and Raman spectroscopy (Raman) spectroscopy elucidate a cooperative layer-insertion/nanopore-filling mechanism governing sodium storage in the plateau region. Furthermore, theoretical simulations reveal that Zn-N4 sites do not dominate the Na-storage behavior alone, but cooperate with the hierarchical pore structure by optimizing the local sodium ions (Na+) adsorption strength and facilitating ion transport. Compared with pure carbon nanopores, Zn-N4 modified nanopores show moderated Na+ binding over the whole pore-size range, indicating a more balanced interaction between Na+ and the carbon framework. This work highlights the advantages of integrating an ordered hard carbon framework with single-atom sites and provides new insights into high-performance sodium storage. The synergistic combination of hierarchical nanopores with single-atom sodium-affinity sites offer a general design paradigm for next-generation sodium-ion battery anodes.
The crystal structure of fac-tricarbonyl(1,10-phenanthroline-κ2N,N′)-(azido- κ1N)rhenium(I),C15H8N5O3Re
(Walter de Gruyter GmbH, 2025) Ledibane, Mmabatho L; Alexander, Orbett T
C15H8N5O3Re, monoclinic, C2/c (no. 15), a = 18.7508(8) Å, b = 12.2267(6) Å, c = 15.8442(11) Å, β = 123.6160(10)°, V = 3025.0(3) Å3, Z = 8, Rgt(F) = 0.0377, wRref(F2) = 0.0902, T = 292 K.
Engineering titanium dioxide-reduced graphene oxide nanocomposite for electrooxidation of nitrite as a surrogate for electrochemical sensing of NO2
(Elsevier Ltd., 2026) Leve, Zandile D; Januarie, Kaylin; January, Jaymi Leigh; Oranzie, Marlon; Sanga, Nelia A; Uhuo, Onyinye; Ross, Natasha; Pokpas, Keagan; Iwuoha, Emmanuel
Nitrogen dioxide (NO2) is a reddish-brown irritating gas characterised by sharp and biting odour. Its detection is imperative as it is harmful to the respiratory system and contributes to the acid rain formation. Aqueous NO2 gas is converted into nitrite (NO2−) ion in solution, which is considered an environmental pollutant with consequential health effects. Oxidation of NO2− has been reported to provide provisional insights for that of NO2 gas in electrolyte. However, detection of NO2− at electrode surface is encountered by difficulty due to high overpotentials. This study presents electrochemical behaviour of a titanium dioxide/reduced graphene oxide-palladium/silver nanocomposite-modified screen-printed carbon electrode (TiO2/rGO-PdAg/SPCE) for the detection of NO2− as a surrogate for NO2 oxidation mechanism in aqueous NaClO4 as electrolyte. Comparative analysis demonstrated superior performance of TiO2/rGO-PdAg/SPCE over bare, TiO2, and TiO2/rGO modified SPCEs due to the synergistic effect of its components. The sensor exhibited a broad detection range of 0.1 – 10 mM and a linear response at 0.1 – 1.4 mM with a limit of detection (LOD) = 1.07 µM NO2− and a sensitivity of 44.38 µA/mM. Simultaneous detection of NO2−and S2O32−demonstrated that the oxidation peak of the former was favoured while the latter was not observed in the investigated potential range. However, adsorption of S2O32− exhibited interference with a decrease in sensitivity to 24.15 µA/mM, which limits the selectivity of the sensor for oxidation of NO2−. Reproducibility exhibited an RSD of 4.18 % at five different electrodes, and stability tests with 74.02 % of peak current retained from initial response for a 12-day period. The recovery of NO2 gas in aqueous medium was studied using calibration curve of NO2−, with average of the triplicate experiments corresponding to 0.4 mM NO2−. These observations present TiO2/rGO-PdAg/SPCE sensor as a potential for reproducible, sensitive, and selective detection of NO2 in environmental monitoring.

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