Electrochemical Measurements Research Articles

Comparative Study of Volatile Corrosion Inhibitors in Various Electrochemical Setups

Volatile corrosion inhibitors (VCIs) are increasingly used in closed systems affected by atmospheric corrosion. In order to achieve a satisfactory level of protection, an inhibitor must be present in a sufficient concentration that should be determined experimentally. Electrochemical measurements are indispensable in corrosion studies examining the protection efficiency of corrosion inhibitors. Volatile corrosion inhibitors are often examined by electrochemical measurements conducted in a bulk of electrolyte, although they protect metal surfaces from atmospheric corrosion where a thin film of electrolyte is present. The aim of this work is to study the protection of carbon steel by two VCIs on different types of electrodes that allow electrochemical tests in a thin electrolyte film and to compare the obtained results with those obtained in a larger volume in a classical electrochemical cell. For this purpose, disc and comb-like electrodes are used. The investigations are carried out in two corrosion media simulating either a marine or urban polluted atmosphere. Studies are performed on low-carbon S235JR steel, which is typically used for crude oil tank bottoms that often suffer from atmospheric corrosion and are increasingly protected by VCIs. Two benzoate-based VCIs recommended for such application are selected for this study.

Graphene–Nickel Oxide–Polyaniline Ternary Nanocomposite‐Embedded Epoxy Coating on Mild Steel for Corrosion Protection

The present work addresses the synthesis and application of graphene‐based ternary nanocomposite for anticorrosion performance to protect mild steel in an accelerated corrosive environment. The chemically‐functionalized graphene‐nickel oxide (Gr‐NiO)‐PANI ternary nanocomposite is synthesized by the hydrothermal reduction of graphene oxide (GO) and nickel salt in the presence of urea, followed by interfacial wrapping of Gr‐NiO by in situ grown polyaniline (PANI). The transmission electron microscopic images reveal the wrapping of Gr‐NiO by PANI in the Gr‐NiO‐PANI ternary nanocomposite. The spectroscopic analyses (Fourier transform infrared and Raman) suggest the multiple interactions between Gr‐NiO and interfacially grown PANI in Gr‐NiO‐PANI. The thoroughly blended Gr‐NiO‐PANI ternary nanocomposite into epoxy matrix via interfacial interactions provides uniform coating (thickness: 87 ± 6 μm) on mild steel and increases the hardness by 160%. The corrosion inhibition performance of PANI, Gr‐PANI, and Gr‐NiO‐PANI nanocomposites in epoxy coating is probed based on electrochemical and salt spray measurements in a 3.5% NaCl solution. The Gr‐NiO‐PANI in the epoxy coating substantially enhances the total impedance and protects the underneath mild steel. The salt spray tests further corroborate the electrochemical results and demonstrate substantial enhancement in corrosion inhibition by Gr‐NiO‐PANI nanocomposite with no sign of corrosion even after 10 days, revealing its potential to mitigate corrosion of mild steel‐based structural and engineering installations.

One-Step In Situ Electrochemical Synthesis of Polyaniline/CeO2 Composite Coating for Enhanced Corrosion Protection of Mild Steel

The electrolytic composition significantly influences the structure and corrosion protection performance of polyaniline (PANI) coating. In the present work, oxalic acid and benzoic acid were employed to electropolymerize PANI coating on a mild steel substrate using the cyclic voltammetry (CV) technique. Then, cerium nitrate was introduced into the benzoic acid medium to electrochemically synthesize a PANI/CeO2 composite coating in situ. Scanning electron microscopy, X-ray photoelectron spectroscopy and electrochemical measurements were used to characterize the coating structure and corrosion resistance. The results suggested that the PANI coating prepared from benzoic acid electrolyte possessed a neater structure and better anti-corrosive properties. The co-deposition of CeO2 further increased the thickness and improved the compactness of the PANI coating. The synthesized PANI/CeO2 composite coating possessed the smallest corrosion current density and the largest inhibition efficiency of 98.2%. The charge transfer resistance and coating resistance also increased significantly after the implantation of CeO2 in the PANI coating. The enhanced corrosion protection performance of the PANI/CeO2 hybrid was also elucidated.

Commercial SiO Encapsulated in Hybrid Bilayer Conductive Skeleton as Stable Anode Coupling Chemical Prelithiation for Lithium-Ion Batteries.

Although Silicon monoxide (SiO) is regarded as the most promising next-generation anode material, the large volume expansion, poor conductivity, and low initial Coulombic efficiency (ICE) severely hamper its commercialization application. Designing a multilayer conductive skeleton combined with advanced prelithiation technology is considered an effective approach to address these problems. Herein, a reliable strategy is proposed that utilizes MXene and carbon nanotube (CNT)as dual-conductive skeletons to encapsulate SiO through simple electrostatic interaction for high-performance anodes in LIBs, while also performing chemical prelithiation. Various characterizations and electrochemical measurements indicate that both MXene and CNT, as conductive networks and buffer interfaces, synergistically enhance the electron transport and lithium storage properties of the electrode. Moreover, the chemical prelithiation process effectively improves the ICE and cycling stability. Consequently, the prepared SiO@MXene@CNT anode delivers a high capacity of 1032 mAh g-1 after 200 cycles at 200mA g-1 and an ultrahigh capacity retention rate of 89.5% beyond 1000 cycles at 1000mA g-1. More importantly, the ICE of the SiO@MXene@CNT anode increases from 65.1% to 92.3% after chemical prelithiation. The work opens a new avenue for significantly improving the lithium storage performance of SiO-based anodes and is expected to promote their commercialization progress.

Understanding the Role of Potential and Cation Effect on Electrocatalytic CO2 Reduction in All-Alkynyl-Protected Ag15 Nanoclusters.

Atomically precise metal nanoclusters (NCs) have emerged as an intriguing class of model catalysts for electrochemical CO2 reduction reactions (CO2RR). However, the interplay between the interface environment (e.g., potential, cation concentration) and electron-proton transfer (ET/PT) kinetics─particularly in alkynyl-protected metal NCs─remains poorly understood. Here, we combined first-principles simulations and electrochemical experiments to investigate the role of potential and cation effect on CO2RR performance in a prototype all-alkynyl-protected Ag15(C≡C-CH3)+ cluster. Our simulations revealed that the applied reduction potential triggers the elimination of the alkynyl ligand via sequentially breaking two π-type Ag-C bonds and one σ-type Ag-C bond to expose the catalytically active Ag sites, and the barrier of the Ag-C breakage monotonically decreases with the lowering in potential. Furthermore, we show that introducing the inner-sphere Na+ ions greatly enhances *CO2 activation and promotes proton transfer to generate *COOH and *CO by forming the Na+-CO2(*COOH) complexes, while the competitive hydrogen evolution reaction (HER) from water dissociation is greatly suppressed, thus dramatically improving the selectivity of CO2 electroreduction. The electrochemical measurements further validated our predictions, where the CO Faradaic efficiency (FECO) and current density (jCO) show a pronounced dependence on the Na+ concentration. At an optimal concentration of 0.1 M NaCl, FECO can reach up to ∼96%, demonstrating the crucial role of cations in promoting the CO2RR. Our findings provide vital insights into the atomic-level reaction mechanism of the CO2RR on alkynyl-protected Ag15 NCs and highlight the important role of potential and electrolyte cation in governing the electron/proton transfer kinetics.

The measurement of phenols with graphitic carbon fiber microelectrodes and fast-scan cyclic voltammetry

A phenol contains a six-membered, conjugated, aromatic ring bound to a hydroxyl group. These molecules are important in biomedical studies, aromatic food preparation, and petroleum engineering. Traditionally, phenols have been measured with several analytical techniques such as UV-VIS spectroscopy, fluorescence, liquid chromatography, and mass spectrometry. These assays provide for relatively high sensitivity and selectivity measurements, but they suffer from relatively low spatiotemporal resolution, low biocompatibility, long analysis time, high cost, and complex sample treatment. Recently, electrochemistry has served as a viable alternative to the measurement of phenols. In this study, we utilized carbon fiber microelectrodes (CFMEs) with fast-scan cyclic voltammetry for the sensitive and selective measurement of phenols. We tested four common phenolic compounds: phenol, 2-methylaminophenol (2-MAP), 4-methylaminophenol (4-MAP), and 3-hydroxybenzoic acid (3-HBA). We found that phenol, 2-MAP, 4-MAP, and 3-HBA were all partially adsorption and diffusion controlled to the surface of the CFMEs and that all four molecules could be detected with repeated injections. Structural differences led to varied sensitivities amongst the four phenols, and we were able to co-detect and differentiate the phenols in complex solutions with dopamine and serotonin. Lastly, we measured the phenols in simulated urine with a high percent recovery. These assays demonstrate enhanced electrochemical measurement of phenols, which will create more effective diagnostics for these complex molecules to help elucidate their mechanistic properties and ultimate significance in a biological context.

Overcoming the Tradeoff Between Reaction Rate and Overpotential in Dinuclear Cobalt Complex Catalyzed Electrochemical Water Oxidation

This study focuses on enhancing the water oxidation reaction (WOR) efficacy of dinuclear cobalt complex catalysts from both kinetic (turnover frequency, TOF) and thermodynamic (overpotential, η) perspectives. For this purpose, we synthesized six dinuclear cobalt complexes 1–6 comprising non‐innocent ligands with different electronically active substituents (‐OMe (1), ‐Me (2), ‐H (3), ‐F (4), ‐Cl (5), and ‐CN (6)). The electronic effects on the electrochemical WOR under neutral, acidic, and alkaline conditions were investigated experimentally and computationally. X‐ray crystallography revealed that the valence state of the cobalt complexes was affected by electronic effects, affording different catalytic potentials, as evidenced by electrochemical measurements. Kinetic and spectroscopic studies confirmed that the synergistic effect of catalyst identity and reaction media changes the reaction mechanism of each catalyst. The WOR performance of 1–6 was tunable through ligand electronics and solvent effects, with the log(TOF)‐η analysis highlighting an operational η as low as 40 mV. This study provides valuable insights into optimizing WOR catalysis through molecular design and environmental tuning.

Tandem Active Sites in Cu/Mo‐WO3 Electrocatalysts for Efficient Electrocatalytic Nitrate Reduction to Ammonia

AbstractElectrocatalytic NO3− reduction to NH3 is a promising technique for both ammonia synthesis and nitrate wastewater treatment. However, this conversion involves tandem processes of H2O dissociation and NO3− hydrogenation, leading to inferior NH3 Faraday efficiency (FE) and yield rate. Herein, a tandem catalyst by anchoring atomically dispersed Cu species on Mo‐doped WO3 (Cu5/Mo0.6‐WO3) for the NO3RR is constructed, which achieves a superior FENH3 of 98.6% and a yield rate of 26.25 mg h−1 mgcat−1 at −0.7 V (vs RHE) in alkaline media, greatly exceeding the performance of Mo0.6‐WO3 and Cu5/WO3 counterparts. Systematic electrochemical measurement results reveal that the promoted activation of NO3− on Cu sites, accompanying accelerated water dissociation producing active hydrogens on Mo sites, are responsible for this superior performance. In situ infrared spectroscopy and theoretical calculation further demonstrate that atomically dispersed Cu sites accelerate the conversion of NO3− to NO2−, and the Mo dopant activates adjacent Cu sites, resulting in the decreased energy barrier of *NO2 to *NO and the stepwise hydrogenation processes, making the synthesis of NH3 thermodynamically favorable. This work demonstrates the critical role of tandem active sites at atomic level in enhancing the electrocatalytic NO3− reduction to NH3, paving a feasible avenue for developing high‐performance electrocatalysts.

Greenhouse Gas Emissions from Molten Fluoride Electrolysis Composed of Raw and Magnet Recycling Derived Oxides: A Comparative Study.

In situ measurements of the chemical identity and quantity of anode gases during electrochemical measurements and rare earth (RE) electrolysis from fluoride-based molten salts composed of different kinds of rare earth oxides (REOs) were performed using FTIR spectrometry. Linear sweep voltammetry (LSV) was carried out to characterize oxidation processes and determine the anodic effect from NdF3 + PrF3 + LiF + REO melt. RE complex formation and subsequent reactions on the GC anode surface were discussed to understand the formation pathways of CO/CO2 and perfluorocarbon gases (PFC), mainly CF4 and C2F6. The LSV shows that increasing the REO content from 1 wt.% up to 4 wt.% in the system, leads to a positive shift in the critical potential for a full anode effect, recorded around 4.50 V vs. W with 4 wt.% REO. The FTIR results from on-line off-gas analysis during LSV measurements indicate that the anode gas products were composed mainly of CO and CO2, whereas CF4 can be detected before the full anode effect and C2F6 at and after this phenomenon. Compositions of off-gases from electrolysis performed using different kinds of REOs were compared. The main off-gas component was found to be CO in RE electrolysis with REOs as raw materials, while in electrolysis with magnet recycling derived oxides (MRDOs), CO2 content was slightly higher compared to CO. PFC emissions during RE electrolysis were generally similar: CF4 was detected periodically, but in negligible concentrations, while C2F6 was not detected.

Chemical Reduction of Cu(OH)2/Cu(O,S) Bilayers Fabricated by Chemical Bath Deposition to Form Adhesive and Low-Resistive Metallic Cu Layers on Glass Substrates

Chemical reductions of Cu(OH)2/Cu(O,S) and Cu(O,S)/Cu(O,S) bilayers fabricated on glass substrates by chemical bath deposition (CBD) was investigated through electrochemical measurements, X-ray diffraction, and evaluations of the electrical properties and adhesion strength by a tape-peeling test. The potential change during the chemical reduction in NaBH4 aqueous solutions was measured and discussed based on a mixed potential theory using the equilibrium potential calculated with chemical thermodynamics. The sheet resistance decreased from over 1 × 108 W/□ to 0.24 W/□, mainly due to the increase in the thickness, with the resistivity estimated to be 4.8 × 10–6 W cm. The metallic Cu layer showed adhesion strengths of 6.4 and 4.4 N cm−1 for maximum and average values respectively by tape-peeling test, without any detachment, but the Cu sheet peeled off from the glass substrate after the complete chemical reduction of the Cu(OH)2/Cu(O,S) bilayer. The Cu fragments formed by the chemical reduction of the Cu(O,S)/Cu(O,S) bilayer peeled off from the glass substrate, but the Cu(O,S)/Cu(O,S) bilayer showed the adhesion strengths of 6.7 and 4.0 N cm−1 for maximum and average values, respectively, by the tape-peeling test. Both the Cu(OH)2 and Cu(O,S) layers were indispensable to secure the Cu layer on the glass substrate.

An active-conductive layer stacked sensor platform for real-time detection of heavy metal ions

The development of electrochemical sensors with high sensitivity and accuracy is crucial for the detection of low-concentration heavy metal ions (HMIs) such as Pb(II) and Hg(II), which remains challenging. To address this issue, MgFe-layered double hydroxide (MgFe-LDH) is synthesized as an active layer on the conductive layer SnO2 loaded with nickel foam (NF) with the assistance of oxygen vacancies (OVs) to form an active-conductive layer stacked sensor. The results show that MgFe-LDH@SnO2/NF exhibits superior sensitivity (Pb(II): 417 μA/μM; Hg(II): 986 μA/μM), wider linear range (1.1–2.2 μM) and lower limits of detection (Pb(II): 1.21 nM; Hg(II): 3.7 nM). The high performance of our sensor is attributed to the improved ability to adsorb HMIs via OV reduced binding energy as well as the promoted rapid electron transport via SnO2 reduced charge transfer resistance, as evidenced by density functional theory and electrochemical measurements. Particularly, by combining the newly proposed tiny electrochemical detection network (ECDNet-tiny) and WeChat mini program, we have built a real-time detection platform for Pb(II) and Hg(II) pollution categories and concentrations, which shows high accuracy (0.98) and recovery rate (91.6 %-106.8 %) in the detection of actual water samples. The qualitative and quantitative calculations of electrochemistry is innovatively implemented by deep learning. Besides, smartphones could display detection results transmitted from cloud servers. Thus, this work provides a new sensor platform to improve the sensitivity, accuracy, and intelligence of detecting quintessential HMIs.

CHARACTERIZATION OF SALT CRYSTALS IN SOIL USING ELECTROCHEMICAL MEASUREMENTS

Soil salinization is considered among the most serious problems that affect irrigated lands and food security in the world. It is interesting to develop methods to test soil salinization. In this paper, the electric properties of sand-salt crystals (NaCl) mixtures (SSM) are investigated using electrical impedance spectroscopy. Seven samples were considered by mixing dry sand and salt crystals with different salt mass percentages (SMP) from 0% to 100%. The electrical responses are explored by measuring the electrical impedance and the global conductance for different SSM filling a small capacitive cell. The influence of frequency and SMP on the electrical conductance and the complex impedance are investigated. It was found that the conductance shows high dispersion with SMP at the whole frequency range and a high dispersion with frequency at low and high frequencies (≤ 10<sup>3</sup> Hz and ≥ 10<sup>5</sup> Hz). Impedance diagrams show a frequency dispersion at high and low frequencies that is modeled by an equivalent circuit constituted of three dipoles in series, each one formed by a pure resistance and a constant phase element in parallel. Findings characteristics are directly related to the rate of salt crystals in the samples. Then, the method developed in this work constitutes a non-destructive technique for detecting salt crystals in soils in arid regions and can be used to develop devices for in situ measurements.

Water state variation of membrane electrode assemblies during shutdown purge of proton exchange membrane fuel cells based on fast electrochemical impedance spectroscopy measurements

Water state variation of membrane electrode assemblies during shutdown purge of proton exchange membrane fuel cells based on fast electrochemical impedance spectroscopy measurements

Selective urea electrosynthesis via nitrate and CO2 reduction on uncoordinated Zn nanosheets.

Electroreduction of NO3- and CO2 to urea (ENCU) represents a fascinating strategy to enable waste NO3-/CO2 removal and sustainable urea production. Herein, uncoordinated Zn nanosheets (U-Zn) are developed as a highly selective ENCU catalyst, exhibiting the highest urea-faradaic efficiency of 31.8% with the corresponding urea yield rate of 39.3 mmol h-1 g-1 in a flow cell. Theoretical calculations and electrochemical spectroscopic measurements reveal that the high ENCU performance of U-Zn arises from the critical role of uncoordinated Zn sites that can promote both key steps of *NO2/CO2 coupling and *CO2NH2 protonation to *COOHNH2, while retarding the competitive side reactions.

Waterborne superhydrophobic bio-epoxy coating on Al alloy for corrosion-resistant and self-cleaning applications

Aluminum (Al) and its alloys are important engineering materials in modern industry due to their numerous advantages and have been widely used in various fields, including aerospace, marine, civilian industries and so on. However, they are prone to corrosion and contamination under harsh environmental conditions, particularly in marine environment when exposed to salty water or moisture for a long time, which can adversely affect their aesthetic appearance and desired functionalities or even cause economic losses and serious accidents. To prevent or delay the corrosion, the hydrophilic nature of Al and its alloy surfaces can be transformed to be hydrophobic or superhydrophobic. In this study, we reported an environment-friendly waterborne superhydrophobic bio-epoxy coating (WSBC) without using volatile solvents. The coating is composed of bio-epoxy resin, nano silica, silane coupling agent as well as hydrophobic curing agent, and applied by spin method on Al alloy substrates. The surface morphology and roughness were characterized by a field emission scanning electron microscope (FESEM) and an atomic force microscope (AFM). The WSBC with 22.2 wt% nano silica loading without considering the solvent of DI water displays a water contact angle (CA) as high as 165.8 ± 3.3° and a sliding angle (SA) as low as 5.3 ± 2.5°. Electrochemical measurement results showed that the as-prepared WSBC has a significant shift from −1.160 V to −0.708 V in the corrosion potential (Ecorr) and 3 orders of magnitude decrease in the corrosion current density (Jcorr), indicating excellent corrosion resistance. The WSBC was further proven to function well after immersion in deionized (DI) water and common organic solvents including ethanol and acetone for 48 h, and weathering resistance test. In addition, the as-prepared WSBC also showed good self-cleaning performance. The developed coating is green and no harm to human health and environment. The facile and eco-friendly process is of great importance for many industrial applications which can provide an attractive way towards anti-wetting surfaces for corrosion protection and self-cleaning effect on a variety of engineering substrates.

Hydrothermally Synthesized NiO-SnO2 Nanocomposite as an Efficient Electrocatalyst for Oxygen Evolution Reaction (OER) and Urea Oxidation Reaction (UOR)

This study presents the synthesis and electrochemical evaluation of a NiO-SnO2 nanocomposite as an advanced catalyst for the oxygen evolution reaction (OER) and urea oxidation reaction (UOR) in an alkaline medium. The NiO-SnO2 composite, prepared via hydrothermal synthesis and subsequent annealing at different temperatures (400°C, 500°C, 600°C), demonstrated excellent catalytic performance, and attributed to its unique dual-phase structure comprising monoclinic NiO and tetragonal SnO2. XRD, SEM, and XPS analyses confirmed the material's crystallinity, morphology, and chemical states, highlighting the role of annealing temperature in optimizing structural properties. Electrochemical measurements revealed that the composite annealed at 600°C exhibited superior OER and UOR activities, with overpotentials of 320mV and 140mV, respectively, at a current density of 10mAcm⁻². This enhanced performance is attributed to the synergistic effects between NiO and SnO2, which improve electron transport, active site availability, and catalyst stability. The study underscores the potential of NiO-SnO2 composites for energy-efficient water splitting and urea-rich wastewater treatment.

Kinetics and dynamics of atomic-layer dissolution on low-defect Ag.

Electrochemical metal dissolution reaction is a fundamental process in various critical technologies, including metal anode batteries and nanofabrication. However, experimentally revealing the kinetics and dynamics of active sites of metal dissolution reactions is challenging. Herein, we investigate metal dissolution on near-perfect single-crystal surfaces of Ag within regions of a few hundred nanometers isolated by scanning electrochemical cell microscopy (SECCM). Potential oscillation is observed under constant current conditions for dissolution. The one-to-one correspondence between the dissolution charge and the geometry of the dissolution pit from colocalized imaging allows ambiguous correlation, which suggests that each oscillation cycle corresponds to the dissolution of one atomic layer. The oscillation behavior is further explained in a kinetic model, which reveals that the oscillation comes from the dynamic evolution of the number of different active sites as the dissolution progresses on each atomic layer. In addition to the fundamental interest, the ability to observe layer-by-layer dissolution in electrochemical measurements suggests a potential pathway for developing electrochemical atomic layer etching for fabricating structures and devices with atomic precision.

Experimental and computational studies of cationic Gemini surfactants as corrosion inhibitors for carbon steel in 15% HCl.

In the process of oil and gas exploration, the corrosion of carbon steel pipes results in substantial economic losses, numerous casualties, environmental contamination, and resource waste. The advancement of highly efficient and stable corrosion inhibitors holds significant importance for protecting carbon steel from corrosion during oil and gas exploitation. In this study, two new cationic Gemini surfactants (2CncoesT, where n = 12, 14) were synthesized through a straightforward two-step reaction. Weight-loss tests demonstrated that the inhibition efficiency (ηw%) increases with the increase in temperature. Specifically, the maximum ηw% values for 2C12coesT and 2C14coesT were 98.0% and 98.3% respectively at 85 °C. The adsorption of these surfactants conformed to the Langmuir adsorption isotherm. Electrochemical measurements suggested that the two surfactants functioned as mixed-type inhibitors. The findings obtained from scanning electron microscopy (SEM) were consistent with the experimental outcomes that 2C12coesT and 2C14coesT are efficient corrosion inhibitors for the metal in an acidic environment. The quantum chemical investigation and molecular dynamics simulation (MD) further substantiated the experimental results and offered insights for a deeper comprehension of the inhibition mechanism of Gemini surfactants.

Electrochemiluminescence microscopy for the investigation of peptide interactions within planar lipid membranes.

Understanding the interactions between lipid membranes and peptides is crucial for controlling bacterial and viral infections, and developing effective drugs. In this study, we proposed the use of electrochemiluminescence (ECL) microscopy in a solution of [Ru(bpy)3]2+ and tri-n-propylamine to monitor alterations in the lipid membranes due to peptide action. A planar artificial lipid membrane served as a model platform, and its surface was observed using ECL microscopy during exposure to melittin, a representative membrane lytic peptide. Upon exposure to melittin, the light-emitting process of the [Ru(bpy)3]2+/tri-n-propylamine system through the lipid membrane exhibited complex changes, suggesting that stepwise peptide actions can be monitored through the system. Furthermore, wide-field imaging with ECL microscopy provided an effective means of elucidating the membrane surface at the submicron level and revealing heterogeneous changes upon exposure to melittin. This complemented the spatiotemporal information that could not be obtained using conventional electrochemical measurements.

Nafion coated nanopore electrode for improving electrochemical aptamer-based biosensing.

The transition to a personalized point-of-care model in medicine will fundamentally change the way medicine is practiced, leading to better patient care. Electrochemical biosensors based on structure-switching aptamers can contribute to this medical revolution due to the feasibility and convenience of selecting aptamers for specific targets. Recent studies have reported that nanostructured electrodes can enhance the signals of aptamer-based biosensors. However, miniaturized systems and body fluid environments pose challenges such as signal-to-noise ratio reduction and biofouling. To address these issues, researchers have proposed various electrode coating materials, including zwitterionic materials, biocompatible polymers and hybrid membranes. Nafion, a commonly used ion exchange membrane, is known for its excellent permselectivity and anti-biofouling properties, making it a suitable choice for biosensor systems. However, the performance and mechanism of Nafion-coated aptamer-based biosensor systems have not been thoroughly studied. In this work, we present a Nafion-coated gold nanoporous electrode, which excludes Nafion from the nanoporous structures and allows the aptamers immobilized inside the nanopores to freely detect chosen targets. The nanopore electrode is formed by a sputtering and dealloying process, resulting in a pore size in tens of nanometers. The biosensor is optimized by adjusting the electrochemical measurement parameters, aptamer density, Nafion thickness and nanopore size. Furthermore, we propose an explanation for the unusual signaling behavior of the aptamers confined within the nanoporous structures. This work provides a generalizable platform to investigate membrane-coated aptamer-based biosensors.