Research Articles (Chemistry)

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Olefin selectivity of K-Mn promoters on CoFe-ZSM-5 based catalyst in CO2 hydrogenation
(Frontiers Media SA, 2025) Mdleleni, Masikana Millan; Maseko, Paula; Cele, Mduduzi N.
The conversion of carbon dioxide (CO2), a major greenhouse gas, into light olefins is crucial for mitigating environmental impacts and utilizing non-petroleum-based feedstocks. Thermo-catalytic CO2 transformation into valuable chemicals offers a promising solution to this challenge. This study investigates the effect of potassium (K) and manganese (Mn) promoters on CO2 conversion and C2H4 selectivity over CoFe-ZSM-5 zeolites. Structural characterization via FTIR, pyridine-FTIR, and PXRD confirmed the successful incorporation of K and Mn into CoFe-ZSM-5 at 80°C without significant structural changes to the zeolite framework. BET analysis revealed that metal incorporation did not substantially alter the surface area, while SEM and TEM analyses confirmed the preservation of ZSM-5 spherical morphology. Fixed-bed reactor experiments conducted at 350°C and 20 bar demonstrated that K and Mn synergistically enhanced CO2 conversion efficiency and selectivity toward C2H4. The K-Mn/4Fe4Co-ZSM-5 catalyst (modified with 4% Co and 4% Fe) exhibited the highest performance, achieving 97% olefin selectivity. Furthermore, Mn and K promoters reduce the CO selectivity on the Co-Fe-ZSM-5 catalyst. These findings underscore the critical role of K and Mn in facilitating efficient CO2 activation and directing the reaction pathway toward valuable olefin products. Copyright © 2025 Maseko, Cele and Mdleleni.
Visible light enhanced degradation of sulfamethoxazole by beta zeolite/TiO 2 photocatalyst
(John Wiley and Sons Inc, 2025) Mishra, Ajay; Mabape, Kgaugelo; Mishra, Shivani
A visible light photoactive layered beta zeolite supported titanium dioxide (TiO2) was successfully fabricated, whereby N,Ndimethylacetamide was used for the first time as a stacking agent, and tetramethylammonium hydroxide pentahydrate (TMAOH) as a template for beta structure via sol–gel assisted hydrothermal method. High-resolution transmission electron microscopy (HRTEM) results confirmed homogenous dispersion of spherical TiO2 nanoparticles onto the zeolite. The ultraviolet– visible (UV–vis) diffuse reflectance spectroscopy (UV–vis DRS), and Raman spectral shifts proved that nanocomposite had a visible light redshift bandgap of 2.88 eV for zeolite/TiO2 (3.18 eV, TiO2). Fourier-transform infrared (FTIR) and energy-dispersive X-ray spectroscopy (EDS) analysis of zeolite/TiO2 revealed the presence of a nitrogen atom from NH4OH, causing a redshift of the photocatalysts by substituting oxygen (O) atom from O─Ti─O to form O─Ti─N bond. This photocatalytic removal efficiency for sulfamethoxazole was 82% after 120 min of visible light irradiation at pH 5.5. This photocatalyst has superior visible light activity with k = 0.018 min−1 and 82% performance for SMX degradation compared to some recent zeolite/TiO2 nanocomposite with UV light limitation. The recyclability and stability tests revealed efficient reuse for five cycles without major decline. A Type-II heterojunction system observed suggest a cyclic charge pair transfer whereby an electron moves from a high CB of zeolite into low CB of TiO2, whereas holes (h+) move from a lower VB of TiO2 into higher VB of zeolite.
Electrochemical performance of V2O5//f-CNT asymmetric flexible device for supercapacitor application
(Springer, 2025) Mishra, Ajay Kumar; Bulla, Mamta; Kumar, Vinay
The advancement of flexible supercapacitors has been constrained by the inherent difficulty of fabricating flexible electrodes. In this work, the V2O5 nanostructures were synthesized at different temperatures (120–200 °C) via hydrothermal treatment, followed by calcination, resulting in materials with high porosity and optimized electrochemical properties. The fabricated electrode (synthesized V2O5 at 180 °C) shows a maximum capacitance (178.5 F g⁻1 at 1 A g⁻1 current density) compared to other prepared samples 1 in a 1.0 M Na2SO4 aqueous electrolyte. For practical applications, V2O5 nanostructures were integrated with f-CNTs to fabricate the V2O5//f-CNT asymmetric supercapacitor device, achieving a specific capacitance of 104.4 F g⁻1 at 1 A g⁻1 within a 1.6 V voltage window, signifying improved charge storage capabilities. The device achieved an energy density of 37.12 Wh kg⁻1 and a power density of 800 W kg⁻1 at 1 A g⁻1. The synergistic integration of Faradaic reactions from V₂O₅ with the EDL capacitance of f-CNTs enabled the device to retain 91.2% of its capacitance after 2000 GCD cycles, with enhanced performance sustained up to 5000 cycles. Furthermore, the device demonstrated remarkable flexibility, losing only 4.3% of its capacitance when bent at a 90° angle, underscoring its potential as a high-performance energy storage solution. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.
Luminescence and electroanalytical properties of carbon quantum dots in the context of immunosensor design
(John Wiley and Sons Inc, 2025) Louw, Clementine Juliat; Baker, Priscilla G L; Alemu, Yemataw Addis
Electroanalytical techniques are powerful tools in biological sensing because of their sensitivity and versatility. In recent decades, great attention has been given to the fabrication of electroactive nanomaterial-based biosensors. In this context, carbon quantum dots (CQDs) have received special attention and have been used to develop many sensors because of their remarkable advantages such as high photostability, high solubility and stability in water, biocompatibility, high photoluminescence emission intensities, and simple methods of synthesis. Since they are very small in size, they have high surface area to volume ratios which in turn can allow good catalytic activities of the working electrodes in electrochemical reactions. Being motivated by these advantages, in this work we prepared two types of carbon quantum dots (CQD-COOH and CQD-NH2) and used them to modify screen printed carbon electrodes (SPCEs) for detection of Troponin I (cTnI). These carbon quantum dot – modified SPCE immunosensors have offered promising results for the determination of cTnI with a limit of detection 62 pg/mL and 171 pg/mL, respectively. This simple approach to sensor design further offers valuable insights into the construction of paper based printed electrodes modified with new carbon-based nanomaterials as immunosensors for detection of other biomarkers of various diseases. © 2025 The Authors. ChemElectroChem published by Wiley-VCH GmbH.
Metal-organic frameworks for advancing photocatalytic and electrocatalytic hydrogen evolution
(Elsevier Ltd, 2025) Ramohlola, Kabelo Edmond; Phasha, Mmapule M; Mhlaba, Reineck
This review offers comprehensive overview of the application of metal-organic frameworks (MOFs) in photocatalytic and electrocatalytic hydrogen evolution reactions (HER), essential for clean and sustainable hydrogen production. It explores the distinctive structural characteristics of MOFs, including their high surface area, tunable pore environments, and versatile metal centers, which enable efficient hydrogen generation. It also introduces catenation as a modification strategy, with studies showing that catenated MOF exhibit exceptional porosity, with structures that can reach up to 65 % porosity. The review explores into current developments in MOF-based photocatalysts and electrocatalysts, addressing strategies to enhance their stability, catalytic performance, and electronic properties. Challenges such as scalability, long-term stability, and reaction efficiency are discussed, along with future perspectives for optimizing MOF-based systems for real-world energy applications.
Ultrahigh-efficiency zinc-air batteries enabled by defect-engineered biomass carbon and dynamic nickel redox mediation
(John Wiley and Sons Inc, 2026) Iwuoha, Emmanuel; Huang, Yongfa; Li, Tingzhen
Coupled zinc-air batteries (CZABs) are promising in future energy storage and conversion solutions because of their potential for enhanced energy efficiency and boosted power density. However, sluggish reaction kinetics at the cathode remain a key challenge, leading to cycling instability and insufficient battery performance. In this study, a rational interfacial etching method is developed to fabricate nitrogen-doped and defect-rich carbon catalysts from the low-cost eucalyptus waste. The precise formation of carbon vacancies, driven by synergistic spatial confinement domains and oxygen-containing functional groups exposed on eucalyptus precursors, promotes the reconstruction of pyridinic nitrogen (Py-N) coordination. This induces local electron redistribution, enhancing charge transfer efficiency at adjacent Py-N sites, and optimizing *O/*OH adsorption–desorption kinetics, thereby significantly boosting the electrocatalytic activity for the oxygen reduction reaction. Additionally, the integration of self-adaptive Ni2+/Ni3+ redox pair into the cathode effectively mitigates the oxygen evolution reaction and thus reduces voltage delay by 0.12 V. The resulting CZABs achieve 82% energy efficiency at 5 mA cm−2 and 77% after 400 h, which is rarely reported. This work elucidates the intricate mechanism of defect formation during biomass pyrolysis and presents a scalable, cost-effective strategy for producing high-efficiency catalysts, offering a promising strategy toward advanced energy storage systems.
Meldola’s Blue immobilised onto mesoporous carbon aerogel surface as non-enzymatic electrode matrix for sensitive hydrogen peroxide determination
(Elsevier Ltd, 2026) Ramonnye, Ofentse; Fort, Carmen Ioana; Mbaiwa, Foster
Meldola Blue (MB) immobilised on mesoporous carbon aerogel (CA) (i.e., MBCA) in chitosan (Chi) solution was used as a modifying matrix at a glassy carbon electrode (GCE) and applied for electrochemical detection of H2O2 in a pharmaceutical product. The obtained MBCA composite was morpho-structurally investigated by XRD and N2 adsorption-desorption measurements. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and amperometry were used to estimate the electrochemical (scan rate, pH, etc.) and analytical parameters of H2O2 electro-reduction at the MBCA-Chi/GCE modified electrode. The high sensitivity (1.72 A/M), wide linear range (0.25 – 2.5 μM), and low detection limit (48.8 nM) highlight the importance of the high specific surface area provided by CA, which, when combined with MB, results in an increased electrode active surface area and enhanced H2O2 detection performance. The new developed modified electrode was tested for the electroanalytical detection of H2O2 in synthetic and real samples.
Hydrothermal synthesis parameter engineering and mass loading of polyaniline electrodes for high-performance supercapacitors
(Elsevier B.V., 2026) Mishra, Ajay Kumar; Bulla, Mamta; Kumar, Vinay
The increasing demand for compact, portable, and cost-effective energy storage fuels advancements in supercapacitors, where achieving high capacitance at elevated mass loadings and excellent rate capability with materials like polyaniline (PANI) is key to enhancing energy density without compromising high power density. This study investigates the effect of synthesis temperature of PANI over a range of 60 °C–140 °C and reaction time (3, 5 and 7 h), to enhance its electrochemical performance. Among the various conditions tested, PANI synthesized at 80 °C for 5 h (P-80 °C (5 h)) demonstrated optimal performance. The optimized sample was further evaluated at high mass loadings ranging from 1 to 10 mg cm−2, exhibiting a specific capacitance of 356 F g−1 at 1 mV s−1 for a 1 mg cm−2 mass. Notably, at 7 mg cm−2, the electrode achieved an impressive areal capacitance of 1172 mF cm−2 and a specific capacitance of 167.4 F g−1. A symmetric supercapacitor device configured as PANI//PANI, with a total active mass of 7 mg, employing a hydrogel electrolyte (H2SO4), delivered an areal capacitance of 812 mF cm−2 and a specific capacitance of 117 F g−1 at a scan rate of 1 mV s−1. Furthermore, the device retained 76.2% of its initial capacitance after 5000 charge-discharge cycles at a current density of 10 mA cm−2. These findings highlight the promise of hydrothermally synthesized PANI and hydrogel electrolytes for advancing high-performance supercapacitors.
Multiscale dual-network cellulose hydrogel electrolytes for dendrite-free Zn anode
(KeAi Communications Co., 2026) Iwuoha, Emmanuel; Lang, Aoxue; Liang, Zhiying
Aqueous zinc-ion batteries (AZIBs) have emerged as promising energy storage systems owing to their high safety, low cost, and environmental friendliness. However, their practical application faces critical challenges, including the formation of Zn dendrites and the occurrence of parasitic side reactions. These phenomena not only hinder ion transport kinetics but also cause rapid capacity decay and potential battery failure. To address these limitations, we developed a sustainable double-crosslinked cellulose hydrogel electrolyte by integrating micron-sized cellulose and cellulose nanofibers (CNFs). The hydrogel electrolyte, constructed from cellulose components with distinct size scales, exhibits a well-organized hierarchical porous network structure, which significantly facilitates the migration of zinc ions. Specifically, nanocellulose serves as a reinforcing filler that enhances the mechanical strength of the dual-network electrolyte, thereby inhibiting Zn dendrite growth. Additionally, abundant carboxyl polar functional groups were also introduced as high-affinity Zn2+ binding sites to mitigate side reactions. Consequently, the assembled Zn//Zn symmetric cells with this electrolyte demonstrate superior cycling stability exceeding 1100 h at current density of 0.5 mA/cm2, along with a high-capacity retention of 79.9% after 1000 cycles in the Zn//V2O5 battery. Furthermore, this cellulose hydrogel electrolyte is easily accessible and biodegradable, paving the way for the scalable production of high-performance and environmentally friendly energy storage devices.
Sustainable treatment of acidic coffee wastewater using biomaterials
(Elsevier Ltd, 2026) Mishra, Ajay Kumar; Tsegaye, Genet; Jida, Mulissa
Coffee wastewater (CWW), a byproduct of coffee processing industries, is characterized by high acidity and elevated organic loads, including COD (Chemical Oxygen Demand) and BOD5 (five-day Biochemical Oxygen Demand), which pose significant environmental risks to downstream users. Anaerobic biological treatment is widely recommended to reduce these organic pollutants. However, the low carbon-to-nitrogen (C:N) ratio and acidic nature of CWW inhibit methanogenic microbial activity, limiting both biogas production and treatment efficiency. This study addresses these challenges by evaluating two pH neutralization strategies carbonized coffee pulp (CCP) and lime (Ca(OH)2) prior to anaerobic digestion. To assess the impact of each neutralization method, batch anaerobic digesters were operated under mesophilic conditions (37 °C) using 550 mL of pretreated coffee wastewater with a hydraulic retention time of 25 days. CCP and lime were applied at dosages of 1.8 kg/m3 and 3.5 kg/m3, respectively, to raise the initial pH to the optimal range for methanogenesis (7.5). Results demonstrated that CCP treated samples significantly outperformed lime-treated samples. CCP achieved a 90 % reduction in COD (from 10,240 mg/L to 1024 mg/L), an 85 % reduction in BOD5 (from 5000 mg/L to 750 mg/L), and the highest biogas yield of 4000 mL. In comparison, lime-treated samples achieved 50 % COD and 60 % BOD5 removal, with a biogas yield of 1175 mL. The superior performance of CCP is attributed to its high carbon content (C:N ratio of 42.94:1) and its ability to stabilize pH without causing sedimentation or scum formation. In conclusion, CCP is a more effective neutralizing agent for coffee wastewater treatment than lime, offering enhanced biodegradability, improved nutrient balance, and substantially higher biogas production. Its dual role as a pH stabilizer and organic enhancer makes CCP a sustainable and cost-effective alternative to conventional chemical neutralizers in anaerobic digestion systems.
Understanding PFAS behavior: analysing contamination patterns in surface water and sediment of the apies river, South Africa
(Springer, 2025) Petrik, Leslie Felicia; Okwuosa, Raissa; Nomngongo, Philiswa Nosizo
Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants widely detected in water and sediment worldwide. Despite growing concerns about their ecological and health risks, their distribution in African aquatic environments remains understudied. This study addresses the knowledge gap in PFAS contamination by analysing the spatial and temporal distribution of 18 PFAS in Apies River water and sediment in Pretoria, South Africa. Surface water and sediment samples were collected upstream and downstream of the Apies River during dry seasons. The analysis of PFAS concentrations was conducted using liquid chromatography-tandem mass spectrometry. Statistical analysis, including paired t-tests, non-metric multidimensional scaling, and hierarchical cluster analysis, were applied to determine spatial and temporal trends. The study revealed significant spatial variations in PFAS contamination, with upstream locations consistently exhibiting higher concentrations than downstream. In surface water samples, L_PFBS, 4:2 FTS, 6:2 FTS, and L_PFHpS showed statistically significant differences (p < 0.05) between sites. Perfluorocarboxylic acids were the dominant PFAS class in surface water (50.47–57.15%), whereas perfluorosulfonic acids were more prevalent in sediments. Upstream sediment had higher L_PFHpS (43.00 ng/g), L_PFDS (38.89 ng/g), and L_PFHxS (23.91 ng/g) than downstream (31.96, 27.84, and 18.02 ng/g, respectively). The findings reveal contamination sources and partitioning between surface water and sediments, aiding in water quality management and pollution mitigation strategies.
Characterization of zrc-v-ti-zrc multilayer hydrogen storage thin films prepared by e-beam evaporator
(Elsevier Ltd, 2025) Rampai, Mojesi Monica; Seroka, Ntalane Sello; Khotseng, Lindiwe Eudora
In this study, a physical deposition method was used to prepare a ZrC–V–Ti–ZrC multi-layered stack film that was deposited on Ti and borosilicate glass substrates. The hydrogenation was achieved by thermal annealing of samples at temperatures of 200, 300, 400, and 550 °C in a pure hydrogen environment with a flow rate of 100 sccm for 30 min. RBS revealed that the multilayers are thermally stable, showing no sign of intermixing of layers up to 600 °C. It revealed the presence of oxygen in all the layers with a significant amount. ERDA revealed that a significant amount of H was near the surface and dropped towards the bulk of the samples, which is the middle layers (V and Ti layers) location. The probing towards the inner last layer (buried ZrC layer) of the multilayer stack showed an increase in the H amount detected. H amount decreased as the oxygen amount was increased in the layers indicating the negative impact of oxygen in the system, such that the total H amount in the samples with the TiO (1:1) and VO (1:1) was 99.122 at.% at 200 °C while that of Ti2O3 (2:3) and V2O3 (2:3) was 60.016 at.% at 300 °C indicating a significant change. The optimum temperature for the highest H amount observed was found to be between 200 °C and 300 °C. The as-deposited sample only showed the surface H, which is normally due to the atmosphere's hydrocarbons. The Raman spectroscopy results indicated that there was a significant decrease in the intensity of the D and G peaks due to annealing in a hydrogen environment. This suggests that the extent of hydrogen absorption, which occurs predominantly in the temperature range of 200–300 °C, is inversely related to the intensity of the D and G peaks. There was more formation of the sp3 at temperatures between 200 °C and 400 °C in the samples as seen by the decrease in the sp2/sp3 ratio from 0.13 to 0.003. XRD revealed the presence of diffraction phases, i.e., ZrC (111), ZrC (400), V2O5 (001), Ti (100), Ti (101), and Ti (103) in addition to the TiH2 and the broadening of peaks for the system annealed at 200 °C and 300 °C due the high H amount, which is consistent with ERDA results. These results indicate the suitability of this system in hydrogen storage applications, provided it is optimized by eliminating oxygen contamination.
Efficient removal of mercury Ions stabilized by gold solution using chitosan–guar gum polymer blend in basic media
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Mishra, Ajay Kumar; Tshikovhi, Azwifunimunwe; Mishra, Shivani Bhardwaj
The highly efficient removal of mercury metal ions at a higher pH (basic media) is barely reported in the literature. In this study, we developed a novel adsorbent by blending chitosan with guar gum, designed to effectively remove mercury ions from basic media by stabilizing them with a gold (Au3⁺) solution. The FTIR confirmed the compatibility of chitosan and guar gum through hydrogen bonding. The morphology of the blend exhibited an amorphous and porous structure. A mesoporous structure with a surface area, volume, and diameter of 11.843 (m2/g), 0.184 (cm2/g), and 17.072 nm, respectively, was confirmed by BET. The adsorption behavior was analyzed using isotherms and kinetics models, which best fitted with the pseudo-second-order kinetic model and Freundlich adsorption isotherm model, respectively. The adsorbent was shown to be an excellent candidate for the removal of mercury ions in water, with an adsorption efficiency of 92% at pH 12 in 60 min and a maximum adsorption capacity of 370.37 (mg/g).
Simple, rapid, scalable confined synthesis of ultrafine Pt nanoclusters for fuel cells
(Elsevier B.V., 2026) Chidziva, Stanford; Bai, Yiming; Sang, Chengcheng
Small-sized nanoclusters exhibit catalytic activity in electrochemical reactions distinct from the bulk-like properties of nanoparticles 2 nm or larger, yet their surfactant-free synthesis remains a formidable challenge. A scalable microchannel-confined synthesis method enables rapid, controlled formation of 1.12 nm Pt nanoclusters without additional surfactants. Kinetic control achieves a nucleation and growth time of approximately 18.6 s, with heat transfer simulations confirming uniform temperature attainment within 0.5 s. Half-cell and single-cell tests, corroborated by density functional theory (DFT) calculations, demonstrate exceptional performance of these Pt nanoclusters in proton exchange membrane fuel cell (PEMFC), achieving a mass activity 1.9 times that of commercial samples and a rated power density of 1.55 W cm−2. This method can employ multiple capillaries assembled into a capillary bundle to enable parallel experiments, highlighting its scalability and potential to advance hydrogen-electricity conversion technologies.
Dual selective sensing of CH4 and ultra-low NO gas utilizing Ag-decorated CeO2-CuO nanorods: Role of humidity in p-n conductivity transition
(Elsevier B.V., 2026) Pholoana, Maphia G; Malgas, Gerald F.; Morulane, Katlego L.
Detecting hazardous gases like methane (CH4) and nitric oxide (NO) under real-world conditions is a significant challenge for gas sensors. Herein, pure and (0.5–2 wt%) Ag-decorated CeO2-CuO nanorods were prepared using a hydrothermal approach and tested as dual-gas sensors for NO and CH4, with controlled relative humidity (RH). The crystal structures, optical properties, surface adsorption states, and chemical states of the materials were probed using various analytical techniques. The sensors were tested at different temperatures for multiple gases, including benzene, acetone, xylene, carbon monoxide, and CH4. At 175 °C, a 2 wt% Ag-decorated CeO2-CuO nanorods demonstrated a superior response and selectivity towards 10,000 ppm CH4 gas. In comparison, at 200 °C, the 0.5 wt% Ag-decorated CeO2-CuO nanorods showed a remarkable selectivity towards a trace level of (5–100 ppb) NO gas. The sensor showed a notable p-n transition in its electrical response based on the gas and humidity levels. However, an opposite response emerged under humid conditions (RH >50 %), indicating a switch to n-type conductivity. This shift is due to humidity-driven surface hydroxylation, electron donation from Ag nanoparticles, and charge effects at the CeO2-CuO interface. Water molecules on the surface change band bending and increase electron accumulation, promoting n-type behaviour. The sensing mechanism associated with humidity-controlled conduction reversal is discussed in detail
Utilisation of mango seed husk for the production of phenolic compounds and glucose with C1184 enzyme preparation reveals the role of glucuronoyl esters in lignin–carbohydrate linkages in biomass recalcitrance
(Springer, 2025) Alexander, Orbett; Mafa, Mpho Stephen; Mohotloane, Mamosela Marriam
This study assessed mango seed husk (MSH) fractions for producing glucose and phenolic compounds using commercial enzymes. We focused on cleaving lignin–carbohydrate linkages, specifically feruloyl and glucuronoyl esters, to decrease biomass recalcitrance and enhance product extraction. For saccharification studies, we used Sigma’s C1184 cellulase from Aspergillus niger. Characterisation results of ground MSH using phloroglucinol and scanning electron microscopy revealed that it could be separated into a fine fraction, containing less lignin and cellulose fibres with parallel orientation, and a coarse fraction, with higher lignin content and cellulose fibres at an angled orientation. Activity assays and zymogram analysis of the C1184 preparation prior to saccharification studies revealed diverse CAZyme activities associated with distinct proteins, with xylanolytic activity dominating. Saccharification studies with ground MSH found that the C1184 preparation supplemented with feruloyl or glucuronoyl esterases was suitable for extracting phenolic compounds (0.4–1.7% w/w) from MSH while converting up to 20% of the total biomass as glucose. Interestingly, when replacing 50% (w/w) of the C1184 preparation with glucuronoyl esterase, glucose release nearly doubled from both MSH fractions. Additionally, phenolics attached to carbohydrates may be less condensed in the fine fraction, as all three esterases released three-to-five times more phenolics from the fine fraction compared to the coarse fraction with higher lignin content. Saccharification trials with alkali-pretreated ground MSH showed that the C1184 preparation supplemented with β-glucosidase produced low glucose levels (170–250 mg/g dry biomass) from the substrate after 24 h, even at 50 mg/g biomass protein loading. Overall, this work advances our understanding of the importance of lignin–carbohydrate linkages formed via glucuronoyl esters in biomass recalcitrance. Furthermore, our study corroborates the potential of MSH as a valuable feedstock for producing value-added products in the biorefinery sector.
Novel antifouling and photocatalytic immobilized iron-doped cerium oxide@halloysite nanotubes decorated polyethersulfone membranes
(Elsevier B.V., 2025) Mishra, Ajay Kumar; Malatjie, Kgolofelo I.; Moutloali, Richard M.
Novel polyethersulfone (PES) ultrafiltration (UF) membranes were prepared by incorporating different contents of iron-doped cerium oxide-halloysite nanotubes (FC@NHT) nanocomposites onto the PES membranes. The properties of the prepared nanocomposite membranes were investigated using Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), thermo-gravimetric analyzer (TGA) and scanning electron microscope (SEM). The results showed that iron dopped cerium oxide (FC) was indeed successfully loaded on the surface of halloysite nanotubes (HNTs). SEM characterization of FC@HNT/PES membranes showed an increase in pore sizes and microvoids which resulted in an increase in both hydrophilicity and flux due to the impact of FC@HNT. Pure water flux of 2% FC@HNT/PES (M4) was increased from 55.9 L.m−2.h−1 (0% FC@HNT/PES) to 320.4 L.m−2.h−1. The membranes also showed high antifouling properties towards humic acid (HA). This was attributed to the membranes becoming more hydrophilic upon modification. Subsequently, this reduced membrane-foulant hydrophobic interactions and made it difficult for hydrophobic contaminants to be attached onto the membranes surface. Photocatalytic ability of the modified membranes was tested against imidacloprid (IMD) insecticides. The membrane (M4) showed high photocatalytic activity of about 79% in 120 mins and 85.7% in 180 mins. The immobilization of FC onto the surface of the HNTs was for the homogenous dispersion of the nanoparticles and to mitigate the issue of agglomeration. Other remarkable functionalities are also provided by this integration. The membrane's ability to function as system for water filtration and for the degradation of imidacloprid pesticide with high antifouling propensity is by far its most intriguing aspect of this work.
Electro-photovoltaics of grignard metathesis-derived poly(propylene imine) tetra(salicylaldimine)-co-poly(3-hexylthiophene-2,5-diyl) copolymer
(Elsevier Ltd, 2025) Ramoroka, Morongwa E; Tesfay, Hayelom H; Ekwere, Precious; Mokwebo, Kefilwe V; John-Denk, Vivian S; Iwuoha, Emmanuel I.
End-functionalization of polymers and synthesis of copolymers has been reported to be an effective method in tuning intermolecular interactions and electronic energy levels, which is extremely vital for improving the power conversion efficiency (PCE) of organic photovoltaic cells (OPVs). In this work, in-situ synthesis of novel dendritic poly(propylene imine) tetra(salicylaldimine)-co-poly(3-hexylthiophene-2,5-diyl) (P3HT-PSL) copolymer by Grignard metathesis is reported. Prior to performing Grignard metathesis, the poly(propylene imine) tetra(salicylaldimine) (PPI-SL) dendritic core material was synthesized using Schiff base condensation. It is noteworthy that this Grignard metathesis has never been used to grow a linear polymer chain on the four branches of dendritic core material. The properties of synthesized PPI-SL and P3HT-PSL were studied by Fourier-transform infrared (FTIR), small angle X-rays scattering (SAXS), thermal gravimetric analysis (TGA), nuclear magnetic resonance (NMR), ultraviolet–visible spectroscopy (UV–Vis), electrochemical impedance spectroscopy (EIS), photoluminescence (PL), and cyclic voltammetry (CV). Effect of poly(3-hexylthiophene-2,5-diyl) (P3HT) chains on the PPI-SL branches were investigated. The formation of P3HT-PSL was confirmed by NMR, FTIR, TGA, and UV–Vis spectroscopy. Synthesized materials were used as donor materials for OPVs and champion PCE of 0.24 % was achieved for P3HT-PSL based OPV. This work uncovers a new avenue for synthesis of organic donor materials for use in OPVs.
Multiscale dual-network cellulose hydrogel electrolytes for dendrite-free Zn anode
(KeAi Communications Co., 2026) Iwuoha, Emmanuel; Lang, Aoxue; Liang, Zhiying
Aqueous zinc-ion batteries (AZIBs) have emerged as promising energy storage systems owing to their high safety, low cost, and environmental friendliness. However, their practical application faces critical challenges, including the formation of Zn dendrites and the occurrence of parasitic side reactions. These phenomena not only hinder ion transport kinetics but also cause rapid capacity decay and potential battery failure. To address these limitations, we developed a sustainable double-crosslinked cellulose hydrogel electrolyte by integrating micron-sized cellulose and cellulose nanofibers (CNFs). The hydrogel electrolyte, constructed from cellulose components with distinct size scales, exhibits a well-organized hierarchical porous network structure, which significantly facilitates the migration of zinc ions. Specifically, nanocellulose serves as a reinforcing filler that enhances the mechanical strength of the dual-network electrolyte, thereby inhibiting Zn dendrite growth. Additionally, abundant carboxyl polar functional groups were also introduced as high-affinity Zn2+ binding sites to mitigate side reactions. Consequently, the assembled Zn//Zn symmetric cells with this electrolyte demonstrate superior cycling stability exceeding 1100 h at current density of 0.5 mA/cm2, along with a high-capacity retention of 79.9% after 1000 cycles in the Zn//V2O5 battery. Furthermore, this cellulose hydrogel electrolyte is easily accessible and biodegradable, paving the way for the scalable production of high-performance and environmentally friendly energy storage devices.
Size engineering of Ni nanoparticles via dual templates to enhance zinc-Iodine batteries
(American Chemical Society, 2025) Iwuoha, Emmanuel I; Huang, Wei; Lian, Zheng
Zinc-iodine (Zn-I2) batteries have received widespread attention due to their higher safety, rich resources, and eco-friendly features and show a promising potential for large-scale energy storage. Nevertheless, challenges such as the shuttle effect of polyiodides and sluggish redox kinetics of iodine species during charge and discharge processes hinder their development. This work reports an effective strategy to improve the electrochemical performance of Zn-I2 batteries through the size engineering of nickel nanoparticles on biomass carbon. In situ UV and in situ Raman spectroscopies reveal that the dual-template size engineering strategy enables the catalyst to provide more active sites for adsorption and catalysis of iodine species, thereby enhancing the adsorption capacity of iodine species and accelerating the kinetics of I-/I2 redox conversion reaction. The shuttle effect of polyiodides is also significantly inhibited. Consequently, Zn-I2 batteries with the size-reduced catalyst as the iodine host cathode exhibit superior rate performance, low potential polarization, and long cycle life

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