In this paper, sodium niobate (NaNbO3) was synthesized by the microwave-assisted hydrothermal method at 150 °C for 70 min, followed by calcination at 550 °C for 2 h. X-ray diffraction revealed the coexistence of orthorhombic P21ma and Pbma phases, while scanning electron microscopy showed a one-dimensional rod-like morphology with an average diameter of about 200 nm. The material exhibited a specific surface area of 5.45 m[2]/g, a pore volume of 0.0269 cm[3]/g, and an average pore diameter of 20.52 nm. X-ray photoelectron spectroscopy indicated the presence of defect-related species, while photoluminescence emissions in the blue and green regions provided complementary evidence for defect-related electronic states. The optical band gap, estimated by diffuse reflectance spectroscopy, was approximately 3.56 eV. Mott-Schottky analysis indicated n-type semiconductor behavior and flat-band potential of -0.76 V vs Ag/AgCl. Electrochemical impedance spectroscopy showed improved interfacial charge-transfer behavior under light irradiation. The material exhibited efficient photocatalytic activity, achieving complete degradation of methylene blue (MB) under UV irradiation, with good stability after five successive reuse cycles. Radical scavenger experiments revealed that h[+], ·OH, and ·O2 [-] species are active in the photocatalytic mechanism. The synthesized NaNbO3 demonstrated effective antimicrobial activity against Enterococcus faecalis and Candida albicans, completely inhibiting microbial growth at concentrations ≥1.25 mg/mL. To the best of our knowledge, this is the first evidence of antimicrobial activity against these microorganisms using NaNbO3, highlighting its potential for environmental and biomedical applications.

Embedding photoactive coordination complexes within redox-active layered oxides offers a route to couple molecular excited-state chemistry with inorganic electrode reactions. Here, [Ru(bpy)3][2+]-intercalated layered MnO2 was electrodeposited on a conductive bamboo-charcoal/carbon-nanotube composite and used as an anode for H2 evolution at a Pt cathode. At +1.10 V vs. Ag/AgCl in 0.5 M Na2SO4, three independent experiments yielded 0.87 ± 0.15 mL H2 after 3 h under 300 nm irradiation, 4.4 times the dark value (0.20 ± 0.05 mL), with a faradaic efficiency of 80.3 ± 14.4%. Although incident and estimated absorbed photon flux densities at 450 and 600 nm exceeded those at 300 nm by more than 400-fold, the 300 nm condition produced the largest H2 evolution and total charge, excluding a simple light-intensity or whole-electrode-absorption explanation. Post-electrolysis spectroscopy, ICP-MS, and semiquantitative redox-potential analysis support a model in which photoexcitation of interlayer [Ru(bpy)3][2+] contributes to Mn(III)/Mn(IV)-related redox cycling, while the elementary electron-transfer and ionic charge-compensation pathways remain unresolved. These findings show that interlayer coordination-complex design can couple molecular photoexcitation with redox-active layered oxide electrodes for light-assisted hydrogen generation.

Silver nanoparticles (AgNPs) are broad-spectrum antibacterial materials that remain active against clinically relevant pathogens, but tea-mediated syntheses have focused predominantly on green tea and have generally emphasised potency without linking particle properties to downstream damage of the bacterial envelope. Here, we synthesised AgNPs using white tea (Camellia sinensis) and benchmarked them against a citrate-reduced preparation produced and assayed in parallel. X-ray diffraction identified face-centred-cubic Ag in both preparations; the white-tea product showed no crystalline silver-salt impurity, while the chemical benchmark contained AgCl. The biogenic particles were smaller and less polydisperse, based on electron microscopy and light scattering, and carried a more negative zeta potential (28.3 ± 7.7 nm; ζ = -19.6 ± 0.8 mV; polydispersity index 0.319 versus 0.466). Minimum inhibitory concentrations (MICs), determined independently for Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213 by broth microdilution, were approximately eight-fold lower for the biogenic preparation once normalised to total silver (4.7 versus 38.5 µg mL[-1]). At sub-inhibitory exposures, complementary flow-cytometric, electron-microscopic and time-resolved supernatant absorbance measurements were consistent with damage to the bacterial envelope and release of intracellular material in both organisms. An A 320 particle-scatter tracer additionally identified a sample-processing-related over-subtraction artefact in the A 260 leakage assay. Release was detectable within 1 h, with modest subsequent increases, consistent with early envelope disruption.

The electrochemical carbon dioxide reduction reaction (eCO2RR) on boron-doped diamond (BDD) electrodes predominantly yields formic acid (HCOOH) as the primary product. Redirecting the reaction pathway toward highly valuable carbon monoxide (CO) remains a significant challenge due to the chemical inertness of the BDD surface. Herein, we present an interfacial engineering strategy to tune the product selectivity from HCOOH to CO on BDD electrodes. First, functionalisation of the BDD surface with nitrogen-containing molecules such as aniline and pyrazole effectively captured CO2, successfully directing the reaction pathway toward CO, and established molecular modification as a proof of concept for redirecting selectivity. Second, utilising an aqueous KClO4 electrolyte dynamically facilitated CO production by minimising specific anion adsorption, providing a considerably more facile and practical route to the same selectivity switch. Through systematic optimisation of the eCO2RR conditions in 0.1 M KClO4, we achieved a maximum faradaic efficiency for CO production (FECO) of 72% at an applied potential of -1.9 V (vs. Ag/AgCl; -1.46 V vs. RHE), an electrolyte flow rate of 500 mL min[-1], and an operating temperature of 5 °C. Electrochemical analyses revealed that increasing the flow rate enhanced the CO2 supply by significantly reducing the diffusion layer thickness. Moreover, decreasing the temperature not only increased CO2 solubility but also selectively suppressed the competing hydrogen evolution reaction (HER). Temperature-dependent linear sweep voltammetry experiments further revealed that this suppression is driven primarily by a negative shift of the HER onset potential rather than by any appreciable shift of the CO2 reduction onset. These findings provide fundamental insights into the reaction mechanisms on inert sp[3]-carbon surfaces and demonstrate that interfacial engineering is an effective strategy for developing selective CO2 conversion systems on BDD, although practical implementation will require further advances in electrode fabrication, operating conditions, and energy efficiency.

The low temperature electrocatalysis of CO2 to CO typically requires purified CO2, adding complexity, cost, and energy penalties due to the need for separate CO2 capture and purification processes. Electrochemical reactive capture (e-RCC) is emerging as a simplification of the process. The method combines CO2 capture with amines to form ammonium carbamates which are then reduced to produce CO and H2. Heterometallic polyoxometalate catalysts were evaluated for e-RCC by cyclic voltammetry showing that [SiCu2[II]Ga[III](H2O)3W9O37][9-] had the lowest overpotential and highest turnover frequency. A combination of cyclic voltammetry and controlled potential electrolysis and transport measurements of carbamates through Nafion membranes revealed that commonly used small-molecule carbamates easily traversed membranes and were oxidized at the anode to CO and CO2. To avoid anodic amine oxidation, polyammonium carbamates were prepared, and the method provides an efficient way to convert CO2 captured into valuable carbon monoxide. Controlled potential electrolysis confirmed that [SiCu2[II]Ga[III](H2O)3W9O37][9-] reduced polyammonium carbamate at a negative potential of -1 V vs. Ag/AgCl, forming CO and H2, while other polyoxometalate catalysts yield CO and H2 at more negative potentials of -1.3 V. This research combines the use of polyoxometalates for electrocatalysts for e-RCC and provides a potential pathway to avoid detrimental amine/carbamate anodic oxidation.

This study investigated how electrode design and electrical conditions influence iontophoretic transdermal drug delivery. A low-resistance silver electrode (Ag*) was developed to reduce interfacial resistance and improve the delivery of lidocaine hydrochloride (LID·HCl). In vitro permeation experiments were conducted using pig ear skin mounted on diffusion cells. Iontophoresis was applied under constant current, constant voltage, and battery-powered conditions. Ag* and conventional Ag electrodes were compared as anodes, with an Ag/AgCl cathode. Drug permeation and current profiles were measured over 8 h. Under constant current conditions, LID·HCl permeation through skin increased linearly with current density (r = 0.993). Enhanced permeation was also observed under constant voltage and battery-driven systems. The Ag* electrode produced higher current and greater drug permeation than the conventional Ag electrode at the same voltage due to its microstructured surface, which increased effective surface area and reduced charge-transfer resistance. Skin permeation was governed by current intensity. The Ag* electrode enabled efficient drug delivery even with simple battery systems, suggesting its potential for use in wearable transdermal delivery devices.

Wearable electronics, particularly dry epidermal electrodes, provide human-connected interfaces for recording biopotential signals. However, their practical utility is often hindered by their limited operational longevity and the resulting environmental burden of electronic waste, as most conventional electrodes are discarded after a single use because of performance degradation. Herein, a reusable, soft, and conductive epidermal electrode is reported, fabricated through the precise incorporation of functional additives. By intentionally modulating the polymer chain architecture, a homogeneous composite is developed that exhibits exceptional flexibility, high conductivity (~100 S/cm), softness (~649 kPa), and stretchability (~234%). This molecular-level design promotes strong intermolecular interactions at the skin-electrode interface, facilitating persistent adhesion and conformability to challenging surfaces, including wet, wrinkled, and stretched skin. These properties enable reliable electrocardiography acquisition through 50 repeated attachment and detachment cycles, over which a commercial Ag/AgCl gel electrode became unmeasurable after 20. The applicability of the electrode to human-machine interfaces is further demonstrated by capturing clear electromyography signals of muscle activity during a rock-paper-scissors game. This low-modulus electrode platform offers a route towards repeated-use wearable healthcare systems and soft-robotics applications, with the potential to reduce the waste associated with single-use electrodes.

To address the core challenge of balancing electrical conductivity, mechanical toughness, and biocompatibility in flexible bioelectronic electrodes, this study proposes a PAM molecular bridge directional coupling strategy. We in situ fabricated a CCNFs/PEDOT: PSS-co-PAM (PSM) composite hydrogel, with linear CMC as a control. Via multiscale characterization and molecular dynamics (MD) simulations, we clarified key structure-property links. PAM segments act as "molecular bridges," conferring flexibility and biocompatibility, while their amide groups form high-density hydrogen bonds with CCNF's ordered carboxyl groups. This anchors the 3D rigid CCNF framework to PEDOT: PSS chains, thereby optimizing stress transfer and charge transport. In contrast, CMC's linear structure and ether-linked carboxyl groups yield weak interfacial interactions. MD simulations confirmed the CCPSM system has 1.6× more hydrogen bonds, 3.36× higher interaction energy, and 63.4% lower water diffusion vs. CMC. CCPSM-5 exhibits 2.16 S/m conductivity, 5.7× higher toughness (3.165 MJ·m[-3]), 1.2× higher elongation (746%), plus excellent adhesion, anti-swelling, and dynamic electrical stability on glass and dry/wet skin. As a bioelectrode, it outperforms commercial Ag/AgCl in EMG/ECG signal fidelity and RMS, enabling precise multi-joint motion monitoring. This work resolves the conductivity-mechanical trade-off by leveraging CCNF's 3D reinforcement and interfacial coupling, offering a novel design paradigm for high-performance flexible bioelectronics.

The monitoring of synthetic antioxidants in food products is essential for quality and consumer safety. In this work, we present the very first electrochemical sensing application of mono-Boc-ethylenediamine-functionalized graphene oxide (GO-EnBoc) nanosheets for the sensitive determination of tert-butylhydroquinone (TBHQ), a widely used food preservative. GO-EnBoc was synthesized by covalent intercalation of mono-Boc-ethylenediamine into the layers of graphene oxide and characterized by various techniques. XRD analysis revealed a significant increase in the interlayer spacing from 0.93 nm to 1.20 nm, indicating successful intercalation, and FTIR spectra confirmed the introduction of nitrogen-containing functional groups. Morphological investigations showed a wrinkled, ultrathin layered structure with improved surface accessibility and electron transfer properties. We investigated the electrochemical sensing performance of GO-EnBoc modified glassy carbon electrodes using differential pulse voltammetry (DPV). At around 0.33 V (vs. Ag/AgCl), the modified electrode presented a well-defined TBHQ oxidation peak and a linear response in the concentration range of 0.1-130 µM with a correlation coefficient of 0.99. The sensor exhibited a low limit of detection (LOD) of 95 nM and a limit of quantification (LOQ) of 0.31 µM. Good repeatability (RSD = 2.1%) and reproducibility (RSD = 3.4%) were obtained. The practical applicability of the sensor was confirmed in chips, popcorn, and edible oil samples with a recovery of 92% to 102%. These findings demonstrate GO-EnBoc as an attractive platform for rapid, reliable, and portable electrochemical monitoring of synthetic antioxidants in complex food matrices.

Arsenic (As) is a toxic metalloid that affects over 100 million people worldwide. Bioelectrochemical systems (BESs) offer a new opportunity to catalyze the biological oxidation of arsenite to arsenate, decreasing toxicity and improving subsequent physicochemical separation steps. However, research on arsenic-related electrochemically active microorganisms (As-EAMs) remains limited. This study electrochemically enriched As-EAMs from sediments of a hydrothermal source in northern Chile using a three-electrode cell. Chronoamperometry was run for 116 days at a poised potential of +0.3V (vs. Ag/AgCl) and under open-circuit potential (O.C.P.). Bacterial colonization over carbon cloth electrodes was examined by scanning electron microscopy and flow cytometry, while microbial communities were characterized via 16S rRNA gene sequencing (Illumina MiSeq). Our results indicated that Rhodococcus sp. was the most abundant genus in both conditions, representing over 90% of the relative abundance. Despite this shared dominance, the poised-potential assay showed 27% and 39% dissimilarity in attached and planktonic communities, respectively, relative to O.C.P. This compositional difference was associated with a higher As(III) oxidation rate: 20% under poised potential versus 5.5% for O.C.P. and less than 3.7% for abiotic controls (p < 0.05). This research improves our understanding of As-EAMs and supports the development of novel electro-biotransformation strategies.

Monkeypox (Mpox), a viral zoonotic disease caused by the monkeypox virus (MPXV) remains a significant global public health concern. Current laboratory diagnostics are limited by high biosafety requirements and complex workflows, preventing point-of-care (POC) use. To address these limitations, a disposable, label-free electrochemical immunosensor was developed to detect the MPXV A29 glycoprotein, a highly immunogenic and diagnostically relevant protein. Shape-controlled, reproducible, hollow porous gold sub-microcubes (HPGCs) were synthesized using AgCl as a sacrificial template. The screen-printed carbon electrode was functionalized with poly-l-cysteine and HPGCs bearing a surface-confined 6-(ferrocenyl)hexanethiol probe and antibody for selective antigen binding. Antigen binding attenuates the ferrocene electrochemistry, investigated by voltammetry and impedance spectroscopy. The high surface-to-volume ratio and electrocatalytically active centers of HPGCs enable high loading of ferrocene and antibodies. The surface-confined signaling probe eliminates the need for an external signaling probe, offering a portable, reagent-free POC testing. The sensor offers a wide linear range (0.1-3200 ng/mL), low detection limit (0.1 ng/mL), excellent selectivity against non-target proteins, high reproducibility (RSD = 3.73%), and strong recovery in spiked serum with minimal matrix effects. These findings demonstrate a robust, sensitive, and user-friendly diagnostic strategy for field-based Mpox surveillance in resource-limited settings.

Physiological signal acquisition is essential for medical diagnostics and human-machine interfaces. Motion artifacts and sweat-induced instability present persistent challenges for conventional electrodes, fundamentally limiting their reliability in dynamic or long-term use. Here, we report a Janus hydrogel electrode that combines high electrical conductivity (3 × 10[4] S·m[-1]), strong interfacial adhesion to copper surfaces (2079 J·m[-2]), and low skin-electrode impedance (∼300 Ω). Distinct from conventional Ag/AgCl electrodes, hydrogel electrode uniquely combines hydrophobic protection, high-strain impedance insensitivity (250%) and rapid self-healing, achieving interference-resistant physiological signal monitoring even under vibration and moisture interferences. Notably, coupling with advanced Transformer algorithms optimized for temporal sequence analysis, the electrodes delivered 97.02% gesture recognition accuracy. This system harnesses these gestures to generate robust and intuitive command inputs, paving the way for potential rehabilitation applications, where future clinical validation is required. This work introduces a multifunctional, biocompatible electrode platform that couples reliable physiological monitoring with AI-powered rehabilitation assessment, opening new avenues for next-generation intelligent wearable bioelectronics.

Electrosorption is a promising strategy for removing ionic organic pollutants and in-situ adsorbent regeneration; however, a lack of mechanistic understanding hinders its broader application. This study systematically investigates the potential-dependent adsorption of 21 structurally diverse persistent, mobile, and potentially toxic compounds (PMs/PMTs), spanning cationic, anionic, zwitterionic, and neutral species with and without aromatic moieties. Experiments were conducted at trace concentrations in realistic tap water matrix using activated carbon felt electrodes with tailored surface chemistries across a potential range of -1 V to +1 V (vs. Ag/AgCl). Results demonstrate that electrosorption is governed by superimposed electrostatic and non-electrostatic interactions, strongly modulated by molecular structure. Non-aromatic ions exhibit electrostatically dominated behavior, following bell-shaped curves with maxima at moderate opposite-charge potentials, with adsorption coefficients (Kd) varying by up to 5 log units. In contrast, aromatic compounds show enhanced adsorption under cathodic polarization regardless of charge, indicating potential-induced strengthening of π-π interactions. Oxygen-rich surface chemistries attenuate these effects, limiting Kd variations to ≤ 2 orders of magnitude. Desorption hysteresis in aromatic species identifies a critical boundary for electrode regenerability, suggesting tailored designs for aromatic vs. non-aromatic fractions. This work provides a foundation for the predictive design of electrosorption processes in realistic water treatment scenarios.

Indium sulfide thin films play a crucial role in photoelectrochemical (PEC) water splitting, offering promising strategies to mitigate energy shortages and global warming. In this study, indium sulfide thin films were synthesized via a hydrothermal method, and the effects of sulfur precursors-l-cysteine (LC) and l-cysteine hydrochloride (LCHCl)-along with hydrothermal temperature ramp rates (3 and 10 °C min[-1]) on their crystallographic orientation, morphology, and thickness were investigated. The findings revealed that films synthesized with LC predominantly exhibited the (440) facet, while those synthesized with LCHCl had the (311) facet. Additionally, films produced at 3 °C min[-1] were thicker than those synthesized at 10 °C min[-1]. The film (LC-IS-10) synthesized at 10 °C min[-1] using LC achieved a photocurrent density of 3.7 mA cm[-2] at -0.2 V vs. Ag/AgCl, which outperformed that of LCHCl-synthesized film (LCHCl-IS-10) at the same heating rate (2.6 mA cm[-2]) and those of the films synthesized at 3 °C min[-1] (LC-IS-3: 0.7 mA cm[-2] and LCHCl-IS-3: 2 mA cm[-2]). 2-Hour photocurrent stability assessments indicated that LC-synthesized films (LC-IS-3: 1 mA cm[-2], LC-IS-10: 670 μA cm[-2]) exhibited superior stability to the LCHCl-synthesized films (LCHCl-IS-10: 90 μA cm[-2], LCHCl-IS-3: 33 μA cm[-2]). This improved stability was attributed to their (440) facet, which was structurally more compact and symmetric and exhibited reduced sulfur exposure than the less ordered (311) facet. Although the LC-IS-3 film had the lowest photocurrent density, it showed enhanced stability, owing to the thickness alteration caused by the oxidation of surface S[2-] species. This research provides insights for optimizing material design in PEC water-splitting applications, advancing sustainable energy solutions.

Bioelectrochemistry enables uranium recovery from uranium-contaminated water. Within microbial electrolysis cells (MECs), electroactive biofilm growth is critical, but the impact of electrode potential on biofilm structure and function remains unknown. This study explored variations in micro-structure, extracellular electron transfer, and uranium recovery of Shewanella oneidensis MR-1 biofilms cultivated under different potential shocks from -0.2 to 0.6 V (vs Ag/AgCl) in MECs at -0.2 V. Across this range, uranium recovery exhibited a clear non-monotonic trend, peaking at 0.2 V and exhibiting the most unreliable performance at 0.6 V. At 0.2 V (low potential, LP), the biofilm electrode exhibited 99.72 % uranium recovery with 42.19 % U(IV) reduction. Additionally, transmission electron microscopy revealed needle-like mineral within the inner extracellular polymeric substances (EPS), attributed to moderate c‑type cytochrome (c-Cyts) density (104.89 % of open circuit potential, OCP), suitable charge transfer resistance (Rct, 68.34 % of OCP), and a dense EPS network (bulk density 138.07 % of OCP). At 0.6 V, the biofilm exhibited higher electrochemical activity (c-Cyts 113.15 % and Rct 48.41 % of OCP), but poorer structural stability (EPS bulk density 101.38 % of OCP), causing fluctuating recovery (99.39 % to 94.10 %) and a lower U(IV) proportion (33.90 %). These results indicate that balancing biofilm activity and structural stability is essential for efficient and sustainable recovery of uranium. The LP biofilm electrode achieved 98.09 % uranium recovery with a surface distribution coefficient (Kd,s) of 1.414 L/cm[2] in real mining groundwater. This finding presents a balance model linking biofilm electrode activity and stability, highlighting the necessity of regulating cultivation potential shock.