Batteries are essential for modern energy storage because of their safety and high energy density. To meet the growing global energy demand, significant improvement of existing electrode materials and the development of new ones are required. Achieving this goal demands a deep understanding of electrochemical reactions, degradation pathways, and thermal behavior under realistic operating conditions. Raman spectroscopy, including in situ, operando, and ex-situ techniques, has emerged as a powerful, nondestructive tool for probing these mechanisms at the molecular level. It enables the detection of changes in the molecular structure and composition of electrodes, solid electrolytes, and their interfaces, thereby providing critical insights for enhancing battery performance. This review comprehensively examines the application of Raman spectroelectrochemistry in monitoring structural and chemical transformations during battery operation, such as ion intercalation, electrolyte decomposition, and interfacial reactions. By correlating Raman signatures with key degradation processes, including capacity fading, structural deterioration, and mechanically induced failure, this review underscores the technique's unique role in diagnosing performance limitations and guiding the rational design of durable and efficient energy-storage systems. Finally, current challenges such as methodological standardization, spectral sensitivity, and spatial resolution are discussed, highlighting future directions for operando battery analytics and sustainable energy technologies.
Biosensing has garnered significant attention due to the demand for early disease diagnosis and the interest in biological interfaces where gravimetric response, hydration, mechanical deformation, and charge transfer are intrinsically coupled and dynamically evolving. Quartz crystal microbalance with dissipation monitoring (QCM-D) and electrochemical techniques provide complementary access to interfacial mechanical and electrical properties, yet each alone faces limitations in interpreting the complexity. This review summarizes recent advances in QCM-D- and electrochemistry-based biosensing, discussing strategies for their coupling, with a particular focus on electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D). By enabling simultaneous gravimetric, viscoelastic, and electrochemical measurements at the same interface, EQCM-D offers unique opportunities for real-time correlation of biointerfacial processes. We further highlight emerging challenges in data interpretation arising from the active roles of water and ions and discuss future perspectives toward correlative multimodal EQCM-D platforms for quantitative biosensing and bioelectrochemical studies.
The chiral-induced spin selectivity (CISS) effect presents a promising avenue for enhancing electrocatalytic processes through spin-polarized electron transfers. However, a comprehensive understanding of how nanoscale chirality influences catalytic activity has remained elusive. In this study, we employ scanning electrochemical cell microscopy (SECCM) to directly investigate the oxygen evolution reaction (OER) at individual chiral Au nanocrystals featuring precisely tunable helicoidal morphologies. Such a single-chiral-particle measurement allows the decoupling of the CISS effect from other influencing factors on the intrinsic OER activity. Our finding reveals that chiral D- and L-Au nanocrystals exhibit a 70% increase in OER activity compared to their achiral counterparts. Furthermore, the increasing OER activities of chiral nanocrystals with different helicities were statistically significant (p < 0.001, ANOVA), leading to a positive correlation between spin polarization and chiral-enhanced activity. This single-chiral nanoparticle electrochemical measurement not only provides mechanistic insight into CISS-mediated electrocatalysis but also establishes a design principle for the development of highly efficient spin-selective catalytic nanomaterials.
Understanding the interplay between redox behavior and structural stability is crucial for the development of transition metal oxides in electrocatalysis. In this work, we use both X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) to investigate the electrochemical response of Mn-based perovskite oxides (La1-x Ca x MnO3) under oxygen reduction reaction (ORR) conditions. This dual approach enables tracking of changes in both the oxidation state and local coordination environment. Mn Kβ XES data show that oxidation-state changes are reversible, despite a shift in transition potentials across a range of compositions, including CaMnO3. In contrast, Mn K-edge EXAFS analyses reveal that while LaMnO3 retains structural integrity, CaMnO3 undergoes irreversible structural changes at low potentials, associated with the collapse of the perovskite framework. Intermediate compositions show partially reversible structural behavior. This decoupling of redox reversibility and structural instability, a picture only accessible through the use of XAS and XES, provides critical insight into the complex behavior of these materials under operational conditions. Additionally, our analysis shows that Mn-(II) formation is only detected in CaMnO3 at potentials more negative than 0.4 V (vs RHE). The ORR onset is associated with Mn-(IV) reduction, while peroxide formation correlates with an increased Mn-(III)/Mn-(IV) ratio, supporting a 2e- + 2e- reduction pathway. This study demonstrates the power of XAS and XES analyses to disentangle electronic and structural dynamics, providing a more complete understanding of activity-stability relationships in perovskite electrocatalysts.
This study systematically investigates the impact of thallium (Tl+) on zinc electrowinning from acid sulfate electrolytes, revealing significant concentration-dependent effects. The application of additives to mitigate the detrimental effects of Tl+ was also explored. At concentrations below 0.8 mg/L, Tl+ exhibits slight decrease on current efficiency (CE) and energy consumption (EC), while higher levels (3.0-5.0 mg/L) reduce CE by 7.41-15.37% and increase EC by 9.63-30.25%. Microstructural characterization shows Tl+ induces pore formation and promotes the preferred (110) orientation. The combined results of molecular dynamics (MD), density functional theory (DFT), and electrochemical experiments reveal that thallium codeposition with zinc enhances hydrogen evolution. This enhancement stems from strong Tl+-H2O interactions, characterized by a binding energy of -13.7 eV, which induce bubble accumulation and initiate pore formation. Additionally, the potential difference between zinc (-0.76 V) and thallium (-0.34 V) facilitates localized galvanic corrosion, causing zinc redissolution. Composite additive A1 effectively mitigates these detrimental effects, increasing CE by 3.86%, reducing EC, and restoring compact (110)-oriented growth. Moreover, A1 preferentially adsorbs onto the cathode surface before H2O and Tl+, forming a protective interfacial layer that effectively suppresses the hydrogen evolution reaction (HER), thereby enhancing overall process performance.
Vibrio parahaemolyticus is a major foodborne pathogen widely distributed in aquatic environments and seafood supply chains, necessitating rapid and ultrasensitive detection strategies adaptable to diverse testing scenarios. Here, we present a glycine/ PVP- and tetrahedron-integrated one-pot CRISPR sensing platform (termed GPT-CRISPR) for robust and ultrasensitive nucleic acid detection. The platform introduces chemical regulation into a multienzyme one-pot RAA-CRISPR/Cas13a network, where glycine may help reduce nonspecific Cas13a background activity, possibly through weak competitive interactions, while polyvinylpyrrolidone (PVP) may enhance reaction compatibility through macromolecular crowding and spatial shielding. This coordinated microenvironment enables stable amplification and CRISPR activation within a single closed vessel while minimizing background interference. Upon target recognition, activated Cas13a cleaves uracil-containing, surface-immobilized DNA tetrahedra, translating molecular recognition into amplified electrochemical signals. This transduction strategy enables quantitative detection with a linear dynamic range of 1.5 to 3 × 103 copies μL-1 and a limit of detection of 0.38 copies μL-1. The same chemically regulated one-pot CRISPR framework remains compatible with fluorescence and lateral flow readouts. The assay operates under isothermal conditions and delivers results within 30 min without complex sample preparation. Validation across real-world samples demonstrates robustness in complex matrices. Collectively, GPT-CRISPR integrates chemical stabilization of a one-pot CRISPR framework with electrochemical transduction, defining a robust sensing architecture with adaptable readout capability.
To understand the structure function of the Nip site of acetyl-CoA synthase (ACS), four nickel(II)-thiolates [NiII(Lp-ClPh(BzS))2] (1), [NiII(Lp-ClPh(BzS))2NiII(dppe)](ClO4/BPh4)2 (2/2'), [NiII(Lp-ClPh(BzS))2NiI(dppe)](ClO4) (2red1), and [NiII(Lp-ClPh(BzS))2NiI(dppe)(CO)2](ClO4), (2red1-(CO)2) are synthesized and characterized, where HLp-ClPh(BzS)/dppe is an N2Sthiol/P2 donor ligand. Model 2/2' has a square planar NiIIP2(μ-S)2 moiety and partially resembles the square planar [{(μ-Scys)3X}NiII] module, i.e., the Nip site of ACS. Electrochemistry and DFT calculations reveal that 2 is stable in its 1e- (2red1), 2e- (2red2), and 3e- (2red3) reduced forms, exhibiting no thiol-S detachment of the model site. 2red1 and 2red2 as models enable to examine their thioester formation ability, relevant to the CoA-Ac synthesis by 1e- and 2e- reduced A-clusters, as proposed in paramagnetic and diamagnetic mechanisms of ACS catalysis, respectively, which are debatable. Reactions of 2red1 separately with CO, CH3I, (CH3I + CO), and (CH3I + CO + Ph3CSNa) are examined, and various intermediates/products formed are characterized by means of spectroelectrochemistry and various spectroscopy that reveal acetyl synthesis and deconstruction at the NiP2S2 site, as well as thioester (Ph3C-SC(O)CH3) formation along with 2red2. 2red2 binds CO to form 2red2-(CO)2 but is unable to produce thioester. Combined experimental and theoretical results that give clue to the ability/inability of thioester formation by 2red1/2red2 are described in this paper.
In situ soft X-ray spectroscopy provides direct insight into the electronic structure of electrocatalysts under realistic reaction conditions but remains technically challenging due to the need to combine aqueous electrochemistry with ultra-high-vacuum detection. Here, we present a mesoporous carbon-membrane working electrode assembly (WEA) that enables window-free in situ XPS and NEXAFS measurements during electrochemical reactions. The design integrates a Nafion proton-exchange membrane with a mesoporous carbon-ionomer contact layer and a thin IrO x catalyst layer, providing continuous electronic and protonic pathways and stable hydration through the membrane. By tuning the chamber water vapor pressure to 8 mbar, the WEA maintains a nanometer-thin water layer sufficient for the oxygen evolution reaction (OER) while preserving photoelectron detection efficiency. A robust peristaltic pump integrated with an alumina-bed water vapor dosing system maintains steady-state hydration at 6-10 mbar with <±0.1 mbar variation, enabling reproducible in situ spectra over extended periods. In situ Ir 4f and O 1s XPS reveal oxidation of Ir3+/Ir4+ to Ir4+/Ir5+ and dynamic changes in hydroxyl and lattice oxygen species, while O K-edge NEXAFS identify the formation of potential-stabilized μ2-O and μ1-O oxygen ligand species at OER. The WEA thus provides a quantitative, window-free platform for probing electrochemical interfaces under near-ambient conditions and establishes a general methodology for in situ soft X-ray studies of functional electrocatalysts, closely resembling the architecture and operation of industrial membrane-based water electrolyzers. This approach establishes a reliable methodology for coupling electrochemistry with the element specific soft X-ray spectroscopy under realistic reaction conditions.
This study reveals how the morphology of organic mixed ionic-electronic conductors (OMIECs) controls the mixed ionic-electronic transport of organic electrochemical transistors (OECTs). Two p-type OMIECs with oligoethylene glycol (OEG) side chains, namely P3MEEET and P3MEEMT, are blended with polystyrene (PS) to produce laterally phase-separated morphologies. By varying the ratio between OMIEC and PS, distinct morphologies are created via nucleation and growth and via spinodal decomposition. Furthermore, porous films are fabricated through the selective dissolution of PS, providing a direct comparison between blend and porous structures on OECT performance. In blends, the reduced ion injection area significantly enhances the mobility (μ) and figure of merit (μC*). Due to the hydrophilic nature of the OMIECs, adding pores to the films does not have a positive effect on signal amplification but improves ion storage via side injection and increases the effective volumetric capacitance (C*). Comparing the two OMIECs studied, porous samples based on P3MEEMT experience a greater benefit from electrolyte side injection. Both blend and porous samples are characterized using a range of techniques, including spectroelectrochemistry (SEC), atomic force microscopy (AFM), scanning transmission X-ray microscopy (STXM), quartz crystal microbalance (QCM), along with ex situ and in situ grazing-incidence wide-angle X-ray scattering (GIWAXS) to unravel the mechanism of the mixed ionic-electronic transport from both an ionic and electronic perspective.
Despite the Pt(111)/HClO4 interface being a model system in electrochemistry, its electric double-layer (EDL) behavior deviates significantly from classical models. In the double-layer region (0.40-0.60 VRHE), electrochemical impedance spectroscopy reveals non-ideal capacitance behavior, which is best described by a constant phase element rather than an ideal capacitor. The extent of non-ideal capacitive behavior can be quantified using the CPE exponent (α), in which we observe two distinct regimes: a decrease at potentials away from the potential of zero charge (PZC), and a pronounced minimum at the PZC itself. To interpret these findings, we combine experimental data with two-dimensional numerical simulations solving the coupled Poisson-Nernst-Planck equations. Our findings show that non-ideal capacitive behavior at potentials away from the PZC arises from finite mass transport within the EDL and an inhomogeneous current/potential distribution across the disc electrode, which results from the cell and electrode geometry. The anomalous α minimum at potentials closer to the PZC is the result of a second potential-dependent variable, which we propose to be electrowetting that alters the geometry of the wetted edge of the disk electrode in the hanging meniscus configuration and therefore the corresponding local electric field. These results highlight the critical roles of cell geometry, edge effects, and electrolyte concentration in modulating frequency dispersion. This work provides new physical insights into capacitance dispersion at well-defined interfaces and lays the foundation for more accurate models of electrochemical systems involving confined geometries and interfacial heterogeneity.
Lithium metal batteries are the most promising representative for achieving high-energy-density battery systems. However, interface instability and lithium dendrite growth are important challenges facing large-scale applications. Polymer solid electrolytes have both the rigidity to suppress lithium dendrite growth and the toughness to accommodate interface fluctuations, making them a necessary path for the development of solid-state lithium metal batteries. Solid-state lithium metal batteries still have poor solid contact interfaces, which are affected by multiple effects of interface mechanics and electrochemistry. In this work, polyurethane with excellent mechanical properties was used as the substrate, and the cross-linking reaction of SiO2 aerogel was used to bridge polyurethane and polymethacrylate polymers, to investigate the influence mechanism of the mechanical-electrochemical characteristics of the interface of a solid electrolyte film on the Li+ interface dynamics. Through the synergistic effect of the fluorinated polar groups and silicon oxygen skeleton in the solid electrolyte film, the synergistic effects of increasing Young's modulus, enhancing mechanical stiffness, and improving electrochemical stability and interface compatibility have been achieved, thus establishing the mechanism of the mechanical-electrochemical coupling characteristics of the solid electrolyte film on interface dynamics, providing a perspective for the practical application of polymer solid-state batteries.
Understanding how concentrations of corrosive oxidants evolve under γ-radiation is essential for assessing long-term material performance in nuclear environments. This work integrates in situ differential pulse voltammetry (DPV) with finite-element kinetic modeling to track and interpret the decay of hypochlorite (OCl-) in aerated 0.1 M NaCl at pH ∼9.9 under a dose rate of 725 Gy h-1. Using a three-electrode setup inside a 60Co γ-cell, OCl- was quantified from calibration curves, where concentrations were validated ex situ by UV-vis spectroscopy. For an initial OCl- added concentration of 10 mM, both methods showed a decrease to ∼1 mM after 24 h. Kinetic analysis based on a radiolysis/halogen reaction scheme indicates that HOCl consumption is dominated by OH• abstraction (∼71%), with a secondary contribution from O2 •- reduction (∼22%) and a minor Cl--mediated pathway (∼7%); contributions from e- and H• are negligible at the steady state. The added HOCl drives a pronounced rise in OCl• that feeds back to lower the steady-state OH• level and modulates H2O2 formation. From these kinetics, it is estimated that g HOCl ≈ -0.53 μmol J-1. Beyond validating DPV as an in situ radiation electroanalytical method, the combined measurements and modeling provide a mechanistic basis for OCl- transformation in saline waters, establishing a general radiation-electrochemistry platform for time-resolved detection of radiolysis products relevant to nuclear-waste containment.
High-temperature platinum (Pt) thin films have been widely used in gas-phase devices such as temperature sensors and microheaters, but little has been done in the field of high-temperature electrochemistry, particularly under hydrothermal conditions. In this work, we explored the chemical and mechanical stability of sapphire-supported tantalum-platinum (sapphire/Ta/Pt) electrodes capped at their edges with a conformal Ta/SiO2 layer in 0.1 M H2SO4 at 200 °C under autogenous pressure. A subset of samples was annealed for 10 min in flowing O2 at 650 °C to gauge the impact of the Ta/SiO2 layer on the overall performance of the Pt electrodes in acidic solutions. The temperature and pressure investigated in this work are well above those reported in previous studies on Ta, Pt, and Pt-alloy thin films, particularly those focused on catalyst materials for energy storage and conversion devices. The electrochemically (or electrochemical) active surface area (ECSA) of the Pt electrodes was measured before and after immersion in H2SO4 at 200 °C and used as the primary durability metric, while X-ray photoelectron spectroscopy (XPS), grazing-incidence X-ray diffraction (GI-XRD), and scanning electron microscopy (SEM) tracked changes in surface chemistry and morphology. Results show that both unannealed and annealed electrodes perform well, retaining more than 80% of their initial ECSA after cycling the potential between 0 and 1.4 V at 500 mV/s in 0.1 M H2SO4 at room temperature, constituting a significant first step toward the development of reusable/low-cost sensors for electrochemical studies in hydrothermal systems.
Surface-area normalization is essential for quantitative comparison in electrochemistry, yet ambiguity in what area represents hampers interpretation and reproducibility. We distinguish the real surface area, a geometric measure of surface roughness and structure, from the electrochemically active surface area, defined as the condition-dependent subset of surface sites participating in a specific faradaic reaction. We clarify how double-layer capacitance and adsorption-limited charge-transfer reactions probe different regions of the electrode surface and how their interpretation and reference values determine whether the result corresponds to an apparent area, the real surface area, or the electrochemically active surface area. We further show that commonly used reference values vary strongly with electrode structure, electrolyte composition, and measurement protocol. To address this, we introduce a formalism based on domain-specific linear combinations of surface contributions that enables structurally consistent area estimates. Finally, we propose normalizing current by active-site count as a direct and reproducible measure of intrinsic activity.
Drosophila melanogaster is a genetically tractable model organism with a compact yet functionally rich nervous system, making it ideal for investigating neural mechanisms and modeling neurological diseases. However, its small brain size poses challenges for real-time measurement of neurotransmitter dynamics. Recent advances in electrochemical methodologies, particularly fast-scan cyclic voltammetry (FSCV) and amperometry with carbon fiber microelectrodes, enable high spatiotemporal resolution measurements in vivo. The integration of electrochemistry with optogenetic tools further enhances experimental precision, allowing causal interrogation of neurotransmission. This review summarizes recent advances in electrochemical methodologies for monitoring neurotransmitter dynamics in Drosophila. FSCV has facilitated real-time, chemically selective quantitative analysis of dopamine and serotonin in defined brain regions, providing new insights into their roles in behavior and neurodegeneration, as well as their modulation by antidepressants and ketamine. Amperometry provides complementary capabilities, allowing detection of exocytic release events and quantification of vesicular neurotransmitter content. Amperometric studies have shown that octopamine primarily undergoes partial release at the neuromuscular junction, whereas serotonin in the ventral nerve cord exhibits both partial release and, notably, full vesicular release events. Looking forward, convergence with advanced imaging technologies promises multidimensional views of neurotransmitter signaling and may uncover novel therapeutic targets for neurological diseases. This review highlights key methodological innovations and their applications in Drosophila, underscoring its unique value in bridging molecular neuroscience, behavior, and translational research.
To recycle/remove/protect the cobalt from polycrystalline diamond (PCD), hard alloys, and Co catalyst, this study investigates cobalt's structural features, the inherent properties of the NaCl solution, and the interfacial chemistry at the solid-solution interface. For cobalt, the corrosion dependence on its structure is examined by X-ray diffraction (XRD), ultraviolet photoelectron spectroscopy (UPS), and density functional theory (DFT). In NaCl solution, propertiesincluding dissolved oxygen (DO), electrical conductivity (EC), and viscosityaffect corrosion and electrolysis. Regarding interface science, the corrosion products (Co1.176(OH)2Cl0.348(H2O)0.456, β-Co-(OH)2, and Co2(OH)3Cl) are identified through XRD and X-ray photoelectron spectroscopy (XPS). Chloride ions trigger the conversion of the β-Co-(OH)2 pathway to the Co1.176(OH)2Cl0.348(H2O)0.456 and Co2(OH)3Cl pathways, a novel phenomenon in solid-solution corrosion. The residual rate (RR) of β-Co-(OH)2, designated as RR-(β-Co-(OH)2), is originally defined to describe the transformation, which is detectable via electrochemical impedance spectroscopy (EIS) and modeled using a newly extended electrochemical element Wpc (based on the Finite-Length Warburg and Generalized Finite Warburg components) along with a novelly extended constant phase element (CPE) derived from the traditional CPE model. Furthermore, a new equivalent circuit model for EIS is developed to represent this conversion process in electrochemistry initially at an unstable solid-solution interface, and the concentration dependence of the effect caused by chloride ions is freshly revealed. This work also reveals other significant trends and mechanisms that depend on the NaCl solution concentration.
Electrochemistry involving superconcentrated electrolytes has rapidly gained attention as a transformative approach in electrochemical processes. Superconcentrated electrolytes have emerged as a groundbreaking solution in electrochemical applications, recognized for their nonflammable nature, ecofriendly composition, and expanded electrochemical stability window compared to conventional dilute aqueous electrolytes. The electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are fundamental processes in energy conversion and storage technologies. This study investigates the electrochemical activity of platinum electrodes in lithium-based electrolytes for understanding the electrochemical characteristics from low to high concentration. The HER and OER kinetics in superconcentrated electrolytes were performed to address challenges related to stability and efficiency in high-concentration ionic environments. Highly concentrated electrolytes characterized by their unique solvation structure and extended electrochemical stability potential window offer promising avenues for enhancing energy storage and conversion applications. Through cyclic voltammetry and linear sweep voltammetry, we analyze key parameters such as redox reactions, overpotentials, and kinetic reactions. This study explores the interaction between platinum and highly concentrated aqueous electrolytes to elucidate its influence on catalytic performance. The results provide insights into optimizing platinum-based electrocatalysis for next-generation sustainable energy solutions, highlighting the role of electrolyte composition in dictating reaction kinetics, potential window, and overall electrochemical performance.
Performing organic photoredox reactions in water remains challenging because most catalysts cannot simultaneously solubilize substrates, control nanoscale organization, and maintain activity under aqueous conditions. We report a photoredox-active polyelectrolyte based on a polydehydroalanine (PDha) backbone covalently functionalized with polypyridyl complexes to address some of these limitations. The copolymer undergoes substrate-triggered self-assembly in water, forming photocatalytically active spherical colloidal nanostructures (∼30 nm), as confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The assemblies efficiently catalyze the hydroxylation of arylboronic acids, a representative water-insoluble photoredox transformation. Mechanistic studies using UV-visible spectroscopy, Raman spectroscopy, time-resolved emission spectroscopy, electrochemistry, and density functional theory (DFT) indicate that dual hydrogen bonding between PDha carboxylates and arylboronic acids governs both self-assembly and catalytic performance. The nanostructures retain high activity over multiple cycles. These findings establish adaptive polymer self-assembly as a general strategy for creating enzyme-like, water-compatible photoredox systems and provide a platform for transferring organic photoredox chemistry into aqueous media.
The relatively low theoretical capacity of conventional cathodes has become one of the key bottlenecks in developing high-energy-density lithium batteries. Iron-(III) fluoride (FeF3) cathodes are viable candidates for next-generation energy storage applications by virtue of their elevated theoretical specific capacity derived from conversion-type electrochemistry; nonetheless, their practical realization remains critically impeded by intrinsically poor electronic transport properties and substantial volumetric dilation. Herein, we employed a microfluidic assembly strategy to develop an FeF3/reduced graphene oxide (rGO) composite fabric (FGF) electrode featuring a three-dimensional network structure. In this architecture, rGO sheets are interconnected to form confined spaces that tightly encapsulate FeF3 nanoparticles into egg-roll-like structural fibers, which are further bridged to create a porous network fabric structure. Benefiting from the high conductivity, excellent mechanical strength, and moderate sheet size of rGO sheets, the resulting three-dimensional network structure not only overcomes the low conductivity of FeF3, enabling rapid electron transport, but also effectively suppresses the volume expansion and dissolution-migration of FeF3 particles during charge-discharge processes. Consequently, the as-formed FGF The electrode demonstrated superior electrochemical behavior, maintaining 98% of its initial capacity across the current density range of 0.5-5 A·g-1. Following 1000 charge-discharge cycles at 0.7 A·g-1, the active material preserved a reversible specific capacity of 72 mAh·g-1. This work not only provides an effective strategy for iron fluoride-based conversion cathodes, but also offers insights into the structural regulation of graphene frameworks for high-energy-density lithium-ion batteries, highlighting the critical importance of fluorinated graphene architectures in next-generation cathode design.
Detection of waterborne pathogens benefits from measurement strategies that combine sensitivity with a practical workflow. We report a side-by-side metrological comparison of two orthogonal readouts measured on the same immunomagnetically captured cells using bifunctional Fe3O4 nanoparticles (MNPs) conjugated to anti-E. coli IgG and ferrocene (Fc). Under our protocol, these Fc-IgG MNPs achieved capturing efficiency up to 95% for Escherichia coli (E. coli) K12. The electrochemical readout, performed by a microfabricated chip (via differential pulse voltammetry of Fc) shows concentration-dependent signal suppression upon capture of E. coli K12, with an apparent detection limit as low as 10 cells·mL-1 and a broad dynamic range spanning 101 to 109 cells·mL-1. A complementary on-chip fluorescence readout (via Nile Red staining) provides visual corroboration and specificity support but exhibits reduced analytical sensitivity, approximately 4 orders of magnitude lower than the electrochemical approach, consistent with nanoparticle-induced quenching at lower cell counts. Across model and drinking-water matrices tested, the comparative performance trend is preserved, and the complete workflow can be completed in about 2 h from capture to readout. Taken together, these results present a comprehensive, internally consistent comparison on a single capture construct and clarify when electrochemistry versus fluorescence is fit-for-purpose in the context of immunomagnetic separation. The platform supports low-consumable testing with a reusable, unmodified electrochemical chip, is amenable to multiplexed array formats, and is readily compatible with portable potentiostats for on-site measurements.