Research Articles (Chemistry)

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Reconstructed wood carbon aerogel with single-atom sites for flexible Zn–air batteries
(American Chemical Society, 2025) Iwuoha Emmanuel; Chen, Zehong; Zhong, Linxin
Single-atom catalysts (SACs) have become vital air cathodes for metal−air batteries, but fabricating monolithic SACs with high catalytic activity and mechanical strength is currently lacking. Herein, an all-natural wood carbon aerogel with single-atom sites is reconstructed via modulating the multi-interactions within lignocellulosic components. Cellulose nanofiber (CNF) constitutes an oriented scaffold via physical interweaving and strong electrostatic repulsion, while lignosulfonate, acting as a multifunctional bioligand, coordinates with metal ions and forms hydrogen bonds with CNF to prevent the agglomeration of adjacent metal atoms. The resulting carbon aerogel features a biomimetic channel-ordered microstructure with M−N4 active sites (M = Cu, Fe, and Co), leading to outstanding mechanical elasticity and oxygen reduction and evolution activities with a half-wave potential of 0.881 V. Therefore, the SA-Cu@NCA-based aqueous Zn−air battery (ZAB) exhibits a high specific capacity of 779.3 mA h g−1 and long-term stability, while the flexible ZAB with SA-Cu@NCA as an integrated cathode delivers a high specific capacity and impressive operating stability even under harsh structural deformations. This study presents a viable approach for the sustainable production of flexible SACs for wearable and portable electronics.
Photochemical ozone production along flight trajectories in the upper troposphere and lower stratosphere and route optimisation
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Shallcross, Dudley Edmund; Foster, Allan; Derwent, Richard
Aviation is widely recognised to have global-scale climate impacts through the formation of ozone (O3) in the upper troposphere and lower stratosphere (UTLS), driven by emissions of nitrogen oxides (NOX). Ozone is known to be one of the most potent greenhouse gases formed from the interaction of aircraft emission plumes with atmospheric species. This paper follows up on previous research, where a Photochemical Trajectory Model was shown to be a robust measure of ozone formation along flight trajectories post-flight. We use a combination of a global Lagrangian chemistry-transport model and a box model to quantify the impacts of aircraft NOX on UTLS ozone over a five-day timescale. This work expands on the spatial and temporal range, as well as the chemical accuracy reported previously, with a greater range of NOX chemistry relevant chemical species. Based on these models, route optimisation has been investigated, through the use of network theory and algorithms. This is to show the potential inclusion of an understanding of climate-sensitive regions of the atmosphere on route planning can have on aviation’s impact on Earth’s Thermal Radiation balance with existing resources and technology. Optimised flight trajectories indicated reductions in O3 formation per unit NOX are in the range 1–40% depending on the spatial aspect of the flight. Temporally, local winter times and equatorial regions are generally found to have the most significant O3 formation per unit NOX; moreover, hotspots were found over the Pacific and Indian Ocean.
Global modeling of trifluoroacetic acid surface concentration and deposition from the gas-phase oxidation of a wide range of precursor hydrofluoroolefins
(Royal Society of Chemistry, 2026) Khan, M. Anwar H.; Mendes, Danielle C.; Holland, Rayne E.T.; Garavagno, Maria de los Angeles; Orr-Ewing, Andrew J.; Stanley, Kieran M.; O'Doherty, Simon J; Young, Dickon; Vollmer, Martin K.; Antony, Alvin John; Karamshahi, Fatima; Wallington, Timothy J.; Percival, Carl John; Bacak, Asan; Derwent, Richard G.; Shallcross, Dudley E.
Oxidation of hydrofluoroolefins (HFOs) is a source of trifluoroacetic acid (TFA) in the lower atmosphere. TFA is deposited in precipitation and accumulates in water bodies and at land surfaces and concerns have been raised over its environmental impact. The formation and distribution of atmospheric TFA from the gas-phase oxidation of fifteen HFOs were studied. The deposition of TFA associated with regional emissions of HFOs were examined using a global three-dimensional chemical transport model, STOCHEM-CRI, where hypothetical scenarios with annual emissions of 1, 10 and 100 Gg for each of the HFOs were modelled. Globally, between 54 and 78 Gg year−1 of TFA are produced in scenarios using lower and upper limit TFA yields, respectively. The most significant contributors to the TFA formation are found to be HFO-1234yf (9.9 Gg year−1, 13–18%), HFO-1225yeZ (8.5 Gg year−1, 11–16%), HFO-1225yeE (8.6 Gg year−1, 11–16%) and HFO-1216 (7.5 Gg year−1, 10–14%). The tropospheric global burden and lifetime of TFA are found to be 0.54–0.78 Gg and 3.8 days, respectively. Atmospheric levels of TFA from HFO oxidation are highest in northern mid-latitudes, with up to 1.5–2.0 ppt in Europe, 0.5–0.7 ppt in Asia, and 0.5–0.7 ppt in North America during the northern hemispheric summer. TFA is mainly deposited in North America, Europe, and Asia, with deposition rates of up to 0.5 × 10−3 Mg km−2 years−1, 1.0 × 10−3 Mg km−2 years−1, and 1.0 × 10−3 Mg km−2 years−1, respectively. A metric called the TFA deposition potential (TDP) is proposed that quantifies the extent to which different HFOs contribute towards enhanced environmental TFA deposition, relative to that from the oxidation of the most widely used HFO (HFO-1234yf).
A diffusion-retarded strategy for practical zn–i2 batteries under harsh conditions
(John Wiley and Sons Inc, 2026) Lian, Zheng; Yang, Wu; Wu, Zhenzhen; Zhong, Linxin; Liu, Zhexuan; Chen, Zhongxin; Lian, Guanwu; Iwuoha, Emmanuel Iheanyichukwu; Ocakoǧlu, Kasım; Lu, Jun; Zhang, Shanqing; Zhou, Guangmin; Peng, Xinwen
Zinc–iodine (Zn–I2) batteries attract increasing attention for inherent safety and cost-effectiveness. However, challenges like sluggish iodine kinetics and polyiodide shuttle effect seriously impede their practical viability. Herein, we develop a diffusion-retarded strategy, where carbon cage-encapsulated Cu-doped zno nanoparticles are tailored on scalable carbon paper substrates as iodine cathodes to simultaneously retard polyiodide shuttle effect and accelerate iodine species reaction kinetics. Specifically, the physical barrier formed by carbon cage and porous fiber effectively retards the diffusion of polyiodides, while the intermodulated single-atom Cu sites and adjacent Zn sites in Cu–zno nanoparticles show remarkable catalytic activity and chemisorption for iodine species, respectively. Hence, the obtained Zn–I2 batteries exhibit an ultra-low polarization voltage of 26.7 mv (1 A g−1) and endure an ultra-long cycle life over 40 000 cycles at 5 A g−1. Notably, the batteries maintain over 5000 cycles with a capacity degradation rate of barely 0.007% per cycle at 60 °C, while the capacity decline is 20.8 mah g−1 under −20 °C (vs. 25 °C), as well as over 1150 cycles at a negative/positive (N/P) ratio of 2.5. Overall, high-performance Zn–I2 batteries under harsh conditions through the diffusion-retarded strategy provide valuable guidance for rational cathode designs toward practical Zn–I2 battery systems
Assessing pharmaceuticals in bivalves and microbial sewage contamination in Hout Bay, Cape Town: identifying impact zones in coastal and riverine environments
(MDPI, 2025) Ojemaye, Cecilia Y; Moser, Justin; Petrik, Lesley
This study investigates the implications of sewage contamination in the coastal and riverine environments of Hout Bay, Cape Town, South Africa. Chemical analyses were applied to quantify the presence of pollutants such as pharmaceutical and personal care products (PPCPs) in sentinel marine organisms such as mussels, as well as microbial indicators of faecal contamination in river water and seawater, for estimating the extent of impact zones in the coastal environment of Hout Bay. This research investigated the persistent pharmaceuticals found in marine outfall wastewater effluent samples in Hout Bay, examining whether these substances were also detectable in marine biota, specifically focusing on Mytilus galloprovincialis mussels. The findings reveal significant levels of sewage-related pollutants in the sampled environments, with concentrations ranging from 32.74 to 43.02 ng/g dry weight (dw) for acetaminophen, up to 384.96 ng/g for bezafibrate, and as high as 338.56 ng/g for triclosan. These results highlight persistent PPCP contamination in marine organisms, with increasing concentrations observed over time, suggesting a rise in population and pharmaceutical use. Additionally, microbial analysis revealed high levels of E. coli in the Hout Bay River, particularly near stormwater from the Imizamo Yethu settlement, with counts exceeding 8.3 million cfu/100 mL. These findings underscore the significant impact of untreated sewage on the environment. This study concludes that current sewage treatment is insufficient to mitigate pollution, urging the implementation of more effective wastewater management practices and long-term monitoring of pharmaceutical levels in marine biota to protect both the environment and public health.
Fabrication of iridium-gold nanocomposite for the detection of selective serotonin reuptake inhibitors
(International Association of Physical Chemists, 2026) Barry, Simone; Cupido, Candice; Pokpas, Keagan; Mulaudzi, Takalani; Ngece-Ajayi, Rachel Fanelwa
A comprehensive study of the development of a novel electrochemical sensor based on iridium-gold nanocomposite (IrAuNPs) modified electrodes for the detection of antidepressants, paroxetine (PRX) and citalopram (CIT) was conducted. The sensing platform, based on a glassy carbon electrode, was modified by drop-casting IrAuNPs, which allowed for enhanced conductivity. IrAuNPs, along with their counterparts iridium nanoparticles (IrNPs) and gold nanoparticles (AuNPs), were synthesized from coffee waste extract (CWE) via complete green chemistry. The physicochemical properties of synthesized nanomaterials were characterized using ultraviolet-visible spectroscopy, dynamic light scattering, highresolution transmission electron microscopy, Fourier-transform infrared spectroscopy, cyclic voltammetry and square wave voltammetry. Results showed that the CWE could reduce the respective metallic salts to form mostly near-spherical to spherical IrAuNPs, IrNPs and AuNPs with core sizes ranging from 2.02 nm to 13.27 nm. The electrochemical sensor could determine PRX and CIT in the concentration ranges of 20 to 200 nM and 1 to 10 µM, with detection limits of 0.072 nM and 0.085 µM, respectively. The sensor showed a recovery of 86 to 115.1 %. The proposed sensor demonstrated good precision and accuracy, with excellent sensitivity and selectivity for drug identification in a rapid analysis time, which is crucial for applications in biological matrices.
Proteomic profiling of Alveolar Macrophages identifies loss of lysosomal content as an indicator of nanofiber-induced frustrated phagocytosis
(John Wiley and Sons Inc, 2026) Haase, Andrea; Stobernack, Tobias; Vennemann, Antje
Toxicological research on inhalable fibers, such as asbestos, has identified material morphology (i.e., length and diameter) and bio-persistence as drivers of adverse health effects (e.g., fibrosis, lung cancer, mesothelioma). Although nanofibers may meet these criteria, their small diameters may enable them to adopt different shapes, affecting their toxicity. While nanofiber pathogenicity is still assessed using animal models, the development of alternative in vitro methods relies on a mechanistic understanding of toxicity. Here, we address nanofiber-induced protein changes in alveolar macrophages by analyzing whole cell lysates and supernatants of NR8383 cells exposed to silicon carbide nanofibers, Mitsui-7 carbon nanotubes, and Printex-90. While all materials elicited a similar dose-dependent cytotoxicity, there was a nanofiber-specific release of TNF-α and glucuronidase. Proteomic profiling after treatment with low, non-cytotoxic concentrations confirmed the inflammatory response and revealed a release of 20 lysosomal, luminal hydrolases, including six cathepsins, into the extracellular supernatant. In cell lysates, these hydrolases were decreased, while membrane-associated lysosomal proteins remained unchanged, suggesting that macrophages engulfing long nanofibers release lysosomal content from open membrane pouches during frustrated phagocytosis. Additionally, 17 biomarkers of nanofiber-induced toxicity were identified as potential targets for predictive, animal-free screening. These early markers may be of value for assessing nanofiber toxicity.
IrO2 supported on TiC and Ti2AlC for improved oxygen evolution reaction performances for proton exchange membrane water electrolyzer
(John Wiley and Sons Inc, 2026) Karels, Simoné; Soudens, Franschke Anrid; Singh, Deep Lata; Linkov, Vladimir M; Pasupathi, Sivakumar
Generating a cost-effective precious-metal catalyst is essential for achieving low-cost, large-scale green hydrogen production.Since the majority of the overpotential in the proton exchange membrane water electrolyzer arises during the oxygen evolutionreaction (OER), the remarkable performance of the IrO2 makes it an ideal anodic catalyst. Herein, a simple, straightforwardmethod was used to prepare an IrO2-loaded transition-metal carbide-supported catalyst. The IrO2 nanoparticles were loadedon TiC (IrxTC 1-x) and Ti2AlC (IrxTAC 1-x) at 20 to 80 wt% IrO2 loadings, using the modified Adams fusion method. A diameterof 2 nm was obtained to exhibit improved OER performance in 0.5 M H2SO4 compared with commercial IrO2. The catalystsshowed a uniform distribution of IrO2 nanoparticles on the supports. Overpotentials of 260 and 250 mV were obtainedfor Ir80TC20 and Ir80TAC20 at 10 mA cm−2. The prepared Ir80TC20 and Ir80TAC20 showed good OER activity, delivering−2 −210 mA cm at 1.47 and 1.46 V versus RHE, respectively. The catalysts exhibited OER stability at 10 mA cm for 73 and58 h, respectively, for Ir80TC20 and Ir80TAC20. The precursor solution proved significant recyclability, and the study demonstrateda new approach to rapidly design low-cost, high-performance anodic catalysts for overall OER performance.
Immunosensor enhanced with silver nanocrystals for on-chip prostate-specific antigen detection
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Mokwebo, Kefilwe; Oranzie, Marlon; Okhai, Timothy
An electrochemical immunosensor for the quantification of prostate-specific antigens (PSAs) using silver nanocrystals (AgNCs) is reported. The silver nanocrystals were synthesized using a conventional citrate reduction protocol. The silver nanocrystals were characterized using scanning electron microscopy (SEM) and field effect scanning electron microscopy (FESEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, and small-angle X-ray scattering (SAXS). The proposed immunosensor was fabricated on a glassy carbon electrode (GCE), sequentially, by drop-coating AgNCs, the electro-deposition of EDC-NHS, the immobilization of anti-PSA antibody (Ab), and dropping of bovine serum albumin (BSA) to prevent non-specific binding sites. Each stage of the fabrication process was characterized by cyclic voltammetry (CV). Using square wave voltammetry (SWV), the proposed immunosensor displayed high sensitivity in detecting PSA over a concentration range of 1 to 10 ng/mL with a detection limit of 1.14 ng/mL and R2 of 0.99%. The immunosensor was selective in the presence of interfering substances like glucose, urea, L-cysteine, and alpha-methylacyl-CoA racemase (AMACR) and it showed good stability and repeatability. These results compare favourably with some previously reported results on similar or related technologies for PSA detection.
Engineering biomass-derived porous carbon via pyrolysis for high-performance supercapacitors
(Springer, 2026) Mishra, Ajay Kumar; Sindhu, Sarita; Kumar, Vinay
In the present study, pistachio shells, an abundant bio-waste, were used for the development of activated carbon (AC) using pyrolysis process. Biochar of shells was prepared at varying pyrolysis temperatures in the range 300–750 °C and then activated using KOH. The structural, functional, and morphological properties were analyzed using XRD, FTIR, and FE-SEM, along with detailed textural properties (BET surface area and pore size distribution). The electrochemical performance of working electrode was evaluated using 1 M KOH and the highest specific capacitance was obtained for the AC synthesized from biochar optimized at 600 °C (AC60), which was 304.1 F g⁻¹ at 20 mV s⁻¹ (CV) and 284.8 F g⁻¹ at 1 A g⁻¹ (GCD). The EDLC and diffusive contributions, as defined by the Trasatti method, were 79.1% and 20.9%, respectively. The fabricated symmetric device (AC//AC) offers 103 F g− 1 of specific capacitance at 0.5 A g− 1 with a maximum 14.36 W Kg−1energy density and 2500 Wh Kg− 1 power density with 80% capacitive retention after 10,000 charging-discharging cycles. The results demonstrate that AC derived from pistachio shells is a favourable electrode material for green and efficient high-performance supercapacitors.
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.

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