Abstract This work introduces a solvent-sparing platform for chemical purification that challenges conventional energy-intensive separation methods by exploiting the “wireless” nature of Bipolar Electrochemistry (BE). We present a miniaturized device based on inherently chiral oligo-modified polypyrrole (Ppy) hollow tubes that functions as an ultra-precise, electrochemically-driven pump for complex matrices. The system is actuated wirelessly via an external electric field, inducing asymmetric polarization across the conductive polymer interface and eliminating the need for direct electrical connections. We exploit the inherent chiral affinity of the solid-state polymer interface, quantified by substantial Cyclic Voltammetry (CV) potential differentials (up to 220 mV), as an electrochemical switch to control kinetic selectivity. Crucially, atomistic modeling (DFT/MD) validates this mechanism, revealing that the separation is driven by a differential Gibbs Free Energy of Adsorption (ΔΔG ads ) of 21.2 kJ/mol, which significantly suppresses the effective diffusion coefficient ( D eff ) of the favored enantiomer within the polymer matrix. When applied to the direct purification of neat spearmint oil, this wireless electro-pumping achieved high enrichment of key monoterpenoids ((-)-carvone and (-)-limonene) up to 90% relative purity, while preserving high enantiomeric excess (ee > 90%). This study provides a robust proof-of-concept for integrating computational design with wireless electrochemical actuation for sustainable downstream processing.

WC/W 2 C particle reinforced 420 stainless steel composites were fabricated via laser powder bed fusion. Their excellent wear resistance is offset by poor pitting corrosion resistance. This study investigates how post-processing heat treatments influence microstructure and corrosion behaviour. Heat treatment significantly altered phase composition and particle-matrix interfacial characteristics. Low-temperature tempering at 400°C promoted austenite reversion, achieving the highest austenite fraction (∼62%). This microstructure yielded the highest critical pitting potential ( E pit =0.42 V SCE ) and the lowest corrosion volume loss; however, the deepest and largest pits were also observed under this condition. In contrast, solution annealing reduced pit initiation near particles but decreased overall resistance due to austenite elimination. Annealing at 1050°C or tempering at 600°C caused extensive precipitation of Cr-rich carbides, leading to Cr depletion and severely degraded corrosion resistance. The findings indicate that austenite stabilization through low-temperature tempering is crucial for enhancing pitting resistance, whereas annealing treatments are ultimately detrimental. • Heat treatment tailors phase constitution and particle–matrix interfaces in LPBF MMCs. • Low-temperature tempering promotes reverted austenite and adjust pitting corrosion resistance. • Annealing thickens in-situ reaction layers but reduces pitting sensitivity at particle interfaces. • Carbide precipitation at high temperature depletes Cr and weakens passive stability. • Bipolar electrochemistry resolves pit initiation sensitivity and propagation kinetics.

Bipolar Electrochemistry for Efficient Removal of Methylene Blue from Polluted Water

Water splitting is one of the most efficient approaches to clean hydrogen production. Assessing electrolyzer performance requires evaluating the efficiency of electrocatalysts. Herein, a motion‐based method is presented that combines bipolar electrochemistry (BE) with dynamic, chemically induced electromagnets to probe the electrocatalytic efficiency of water splitting. With this approach, redox reactions are triggered in a wireless way at both extremities of a solenoid‐shaped electrolyzer composed by different metal catalysts. The resulting current follows the helical coil, producing a concentrated magnetic field that drives rotational motion in the presence of an external magnetic field without traditional ferromagnetic materials. A direct correlation between the angular velocity and the catalyst efficiency is obtained. Furthermore, by applying an alternating electric field, the resulting device behaves as a direction‐sensitive dynamic electrolyzer, with its angular velocity determined by which catalyst serves as the anode or cathode, respectively. This strategy provides a simple, wireless readout for catalyst screening, offering a new tool for hydrogen generation research.

Abstract Bipolar electrochemistry is a high‐throughput corrosion testing method capable of applying a quasi‐linear potential gradient across test specimens. This study employs—bipolar electrochemistry corrosion testing to investigate the influence of gravity on pitting corrosion of type 304L and 420 stainless steel across a broad range of applied potentials. Gravity modifies the distribution of current density on the bipolar electrode without altering the potential distribution. The impact of gravity on pitting corrosion is achieved through its effects on the dilution of the electrolyte and the removal of the salt film within the pits. Pits oriented in a face up position demonstrate smoother morphologies, larger cross‐sectional areas and pit volumes. In contrast, pits oriented in perpendicular and facedown positions exhibit pit shape. Under conditions governed by diffusion and activation control, pits can up to over 100 μm. Additionally, crystallographic pits are observed to form in areas subjected to high applied potentials.

Structures that can be stimulated to change shape may be utilized for a variety of applications, but they frequently need to be processed and modified. We propose here a simple, straightforward strategy of actuation based on bipolar electrochemistry driving asymmetric reactions at the surface grooves of pristine carbon fibers. In the first set of proof-of-principle experiments, a free-standing carbon fiber is polarized in a closed bipolar cell to trigger asymmetric benzoquinone/hydroquinone redox reactions in the two distinct compartments. Beyond a particular threshold potential, ion transfer occurs, and the part of the fiber involved in the anodic reaction exhibits reversible directional motion. Elemental surface characterization of the polarized carbon fiber indicates that the deflection is due to the intercalation/deintercalation of ions accompanying the oxidation/reduction of the fiber. The simultaneous local surface ionic adsorption/desorption is responsible for the fiber deflection. The length of the fiber part exposed to the electrochemical reduction reaction in the opposite compartment of the closed bipolar cell, as well as the groove orientation, determines the motion’s intensity and direction, respectively. Effective bending is achieved by optimization of fiber alignment and stimuli parameters. Actuation of two parallel fibers, oriented in opposite directions, leads to microtweezer-type behavior. We anticipate that these results will enrich the tool case for research in the field of soft robotics and micromechanics.

Award of the Electrochemical Society of Japan (ECSJ) in 2025.His current research interests include the electrochemical synthesis of polymeric and functional materials using both conventional methods and bipolar electrochemistry.

The research and implementation of portable and low-cost analytical devices that possess high reproducibility and ease of operation is still a challenging task, and a growing field of importance, within the analytical research. Herein, we report the concept, design and optimization of a microfluidic device based on electrochemiluminescence (ECL) detection that can be potentially operated without electricity for analytical purposes. The device functions exploiting the concept of streaming potential-driven bipolar electrochemistry, where a potential difference, generated from the flow of an electrolyte through a microchannel under the influence of a pressure gradient, is the driving force for redox reactions. To our purpose, we employ such a device to drive the ECL reaction of an organic chromophore deposited onto the electrode surface by simply flowing an electrolytic solution containing a coreactant into the microfluidic system, and we successively apply such device for the detection of amines in water. Our device shows high reproducibility and satisfactory detection limits for tri-n-propylamine, demonstrating an original, and up to now unexplored, concept of energy saving microfluidic systems with integrated ECL detection.

Purpose Low-density steels have gained increasing popularity in industrial applications. However, their corrosion mechanisms remain insufficiently studied. This study aims to investigate the influence of varying Cu content on the microstructure evolution and corrosion resistance of Fe-8.5Al-30Mn-1C low-density steel. Design/methodology/approach Potentio-dynamic polarization tests were conducted to evaluate the critical pitting potential (Epit) at varying Cu contents (0–3 Wt.%). In addition, bipolar electrochemistry was used to investigate the corrosion evolution at different potentials and the susceptibility of pit nucleation sites in low-density steel. Findings The results indicate that the Epit remains unaffected by Cu content, as pit nucleation predominantly occurs at the interfaces between micro-scale carbides and the steel matrix – a process independent of Cu concentration. Although Cu promotes the formation of a corrosion film on the low-density steel, the potential for film formation exceeds that of pitting initiation. Furthermore, the resulting corrosion films exhibit insufficient stability and thickness to enhance pitting resistance. Consequently, Cu alloying does not improve pitting corrosion in low-density steel. Originality/value This study elucidates the influence of Cu on corrosion mechanisms in low-density steel. The findings provide valuable insights for selecting optimal alloying elements to enhance pitting corrosion resistance in low-density steels. Furthermore, the results establish fundamental guidelines for developing highly corrosion-resistant surface films through controlled alloy design.

A dual-Color closed bipolar electrochemiluminescence platform for visual simultaneous diagnosis of two pluripotency markers in cancer patients' urine.

Optical readouts have gained a considerable attention due to their high spatial resolution, high signal to noise ratio and fast response times. Among these, light‐emitting diodes (LEDs) as optical transducers enable to encode chemical information in the current passing through the diode and as a consequence in its light emission amplitude. Recently, the synergy between the principle of bipolar electrochemistry and the optical and electric advantages of LEDs have been explored, in order to develop novel and straightforward approaches to visualize chemical information. This has been increasingly exploited in multiple applications ranging from electroanalysis to chiral recognition, dynamic systems, and multimodal imaging. This review aims to highlight the use of endogenous (thermodynamically spontaneous) and exogenous (externally driven) bipolar electrochemistry for the design of wireless optical readouts based on the operating principle of LEDs.

Electrosynthesis is a powerful method for the synthesis of organic, inorganic and polymeric materials based on electron transfer-driven reactions at the substrate/electrode interface. A different mode of driving electrochemical reactions has been proposed, using bipolar electrodes (BPEs) as wireless electrodes that undergo anodic and cathodic reactions simultaneously. Bipolar electrochemistry is an old technology that has recently garnered renewed attention due to the interesting features of BPEs because (i) the wireless nature of a BPE is useful for sensors and material synthesis, (ii) the gradient potential distribution on BPEs is a powerful tool for the preparation of gradient surfaces and materials, and (iii) electrophoresis is available for effective electrolysis.1 Recent advances in bipolar electrochemistry for the electrosynthesis of functional materials are summarized.2The wireless nature of BPEs has been exploited for symmetry breaking to fabricate anisotropic materials based on the site-selective modification of conductive objects by electroplating and electropolymerization. Potential gradients across a BPE interface have been successfully used as controllable templates to form molecular or polymeric gradient materials, which are potentially applicable for high-throughput analytical devices or as biomimetic materials. The electric field required to drive BPEs is also potentially useful to induce the directed migration of charged species. The synergetic effects of electrophoresis and electrolysis were also successfully demonstrated to obtain various functional materials. These features of bipolar electrochemistry and the various combinations of techniques have the potential to change the methodology of electrosynthesis.

Nickel is a crucial alloying element extensively utilized in stainless steels, high-temperature corrosion-resistant alloys, and, more recently, in high-entropy alloys (HEAs) and multi-principal element alloys (MPEAs). Its unique combination of strength, ductility, and corrosion resistance has made nickel indispensable to industries such as aerospace, automotive, nuclear power, petrochemicals, food processing, and marine applications.Despite its broad usage, the influence of nickel on corrosion resistance, particularly pitting resistance, remains a subject of debate. For instance, Azuma et al observed that adding 4 wt.% Ni to stainless steel containing 25 wt.% Cr and 3 wt.% Mo improved pitting resistance; however, increasing the Ni content to 30 wt.% resulted in a diminished effect due to the microstructural shift from ferritic to austenitic.[1] However, other research has suggested that nickel enhances passivation and pitting resistance,[2] yet it has also been shown to cause preferential dissolution of the ferritic phase in duplex stainless steels.[3] Furthermore, while nickel is not explicitly considered in the standard pitting resistance equivalent numbers (PRENs) formula, it is widely recognized for its role in offering resistance to corrosion, especially for stress corrosion and high-temperature corrosion, through the formation of a protective nickel oxide layer. However, most studies have primarily focused on nickel’s impact on phase composition, microstructure, and mechanical properties rather than its direct influence on Fe-Cr passive films.This present study systematically examines the effect of varying nickel content on the pitting corrosion resistance of Fe-Cr alloys produced via arc melting. In conventional Fe-Cr binary systems, a chromium content of approximately 12 wt.% is necessary to develop a stable passive film.[4] Through cyclic potentiodynamic polarization testing in 3.5 wt.% NaCl, it was found that introducing as little as 3 wt.% Ni to Fe-Cr alloys with over 12 wt.% Cr significantly improved pitting resistance. More notably, in alloys with less than 12 wt.% Cr, nickel's impact was even more pronounced. For example, while an Fe90Cr10 alloy exhibited no passivation, the addition of 20 wt.% Ni facilitated spontaneous passivation, yielding a pitting potential of 0.11 V vs. SCE. To further elucidate nickel’s role in passive film stability, its effects on incomplete passive films (alloys with <12 wt.% Cr) were systematically analysed.The findings of this study offer new insights into nickel's role in the corrosion behaviour of Fe-Cr alloys, contributing to a more comprehensive understanding of its effects on passive film stability and pitting resistance. These insights can aid in optimizing alloy compositions for the development of advanced corrosion-resistant HEAs and MPEAs. Figure. 1 Scheme of the role of Ni in enhancing the corrosion resistance of Fe-Cr Alloys[1] S. Azuma, T. Kudo, H. Miyuki, M. Yamashita, H. Uchida, Effect of nickel alloying on crevice corrosion resistance of stainless steels, Corros. Sci., 2004, 46, 2265 – 2280[2] J. Horvath, H. H. Uhlig, Critical potentials for pitting corrosion of Ni, Cr‐Ni, Cr‐Fe, and related stainless steels, J. Electrochem. Soc., 1968, 8 (115), 791 – 795[3] Y. Zhou, D. L. Engelberg, Fast testing of ambient temperature pitting corrosion in type 2205 duplex stainless steel by bipolar electrochemistry experiments, Electrochem. Commun., 2020, 117, 106779[4] P. F. King, H. H. Uhling, Passivity in the iron-chromium binary alloys, J. Phys. Chem., 1959, 63,12, 2026 – 2032 Figure 1

Ultra-low voltage bipolar electrochemistry: a game-changer for seawater uranium extraction

Spontaneous recharge, and overpotential reduction in symmetric Fe(CN)63-/ Fe(CN)64- batteries, using electrically induced effects and related bipolar electrochemistry

Multicomponent patchy particles offer unique opportunities for diverse applications, yet their controlled synthesis remains challenging. Here a strategy is presented that allows generating complex microparticles, having distinct patches of different chemical composition, by using a one‐pot and single‐step approach. The concept is based on the synergetic combination of bipolar electrochemistry and a water/organic (w/o) interface as the reaction space. Positioning conducting microspheres at the w/o interface allows for targeted surface modification with multiple components. Under the influence of an applied electric field, oriented parallel to the interface, simultaneous redox reactions in both phases lead to the selective deposition of up to four different materials at opposite faces of the particles. This very versatile approach can also be extended beyond spherical particles for the controlled modification of 2D materials. The simplicity of the method and the inherent precise control over multiple functional components allows for the design of advanced multicomponent patchy particles, which cannot be obtained by any other deposition process.

Bipolar electrochemically generated fluorescence detector for microchip electrophoresis with and without a potentiostat: Application to reducible analyte detection.

Redox-active electrosorbents are promising platforms for selective separations. However, these platforms face intrinsic challenges in extracting multiple species simultaneously, as their binding mechanisms are typically tailored to separate a single ion preferentially. Here, bipolar electrochemistry is leveraged to introduce a new strategy for the multiplexed use of redox-active and capacitive materials for separations. Using polyvinyl ferrocene (PVF)-, Prussian blue analog (PBA)-functionalized, and carbon-based electrodes, multicomponent separations within a modular bipolar electrode (BPE) platform are demonstrated. The multiplexed BPE system provides distinct electrochemical environments within each BPE pair, enabling parallel selective separations. With three identical PVF BPEs, arsenic uptake increased linearly from 41.4 to 115.4 mgAs gPVF -1, highlighting the scalability of the system. Moreover, deploying three distinct BPE pairs-PBA, PVF, and carbon-enables simultaneous potassium recovery (11.0 mg g-1), arsenic removal (19.8 mg g-1), and desalination (4.2 mg g-1) from secondary wastewater, demonstrating real-world applicability. This wireless, membraneless architecture enables process-intensified selective separations by precisely controlling local electric fields on individual redox-active materials, facilitating electrosorption and regeneration across diverse BPE systems within a unified process.

ViPER: A visual bipolar electrochemical biosensor based on isothermal addition of a universal tag for detection of SARS-CoV-2.

Glassy carbon electrodes were modified with a CeO2 film and Pt nanoparticles (Pt-CeO2) for electrocatalysis. Interestingly, the oxidation of benzyl alcohol was significantly enhanced when Pt-CeO2 films were prepared by the simultaneous electrodeposition of the two materials, indicating a significant synergistic electrocatalytic activity. Subsequently, bipolar electrochemistry was employed to prepare Pt-CeO2 gradient films. Scanning electrochemical microscopy (SECM) was employed for studying local electrochemical properties at liquid/solid interfaces. SECM allowed mapping the local electrochemical performance of the Pt-CeO2 gradient films for benzyl alcohol oxidation, showing that the reaction rate is proportional to the local Pt-CeO2 surface coverage. Therefore, Pt-CeO2 deposits with different densities along the bipolar electrode offer tunable catalytic performances for benzyl alcohol oxidation. This allows identifying in a fast and straightforward way the optimal conditions for electrocatalytic processes in a more general sense because the approach, illustrated here with one specific reaction, can be easily generalized to other catalytically active surfaces.