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A novel voltammetric sensor based on a self-assembled composite formed by native DNA and electropolymerized N-phenyl-3-(phenylimino)-3H-phenothiazin-7-amine has been developed and applied for sensitive determination of doxorubicin, an anthracycline drug applied for cancer therapy. For this purpose, a monomeric phenothiazine derivative has been deposited on the glassy carbon electrode from the 0.4 M H2SO4-acetone mixture (1:1 v/v) by multiple potential cycling. The DNA aliquot was either on the electrode modified with electropolymerized film or added to the reaction medium prior to electropolymerization. The DNA entrapment and its influence on the redox behavior of the underlying layer were studied by scanning electron microscopy and electrochemical impedance spectroscopy. The DNA–doxorubicin interactions affected the charge distribution in the surface layer and, hence, altered the redox equilibrium of the polyphenothiazine coating. The voltametric signal was successfully applied for the determination of doxorubicin in the concentration range from 10 pM to 0.2 mM (limit of detection 5 pM). The DNA sensor was tested on spiked artificial plasma samples and two commercial medications (recovery of 90–95%). After further testing on real clinical samples, the electrochemical DNA sensor developed can find application in monitoring drug release and screening new antitumor drugs able to intercalate DNA. [ABSTRACT FROM AUTHOR]

Herein, we feature our recent efforts toward the development and application of nanoelectrochemistry at liquid/liquid interfaces, which are also known as interfaces between two immiscible electrolyte solutions (ITIES). Nanopipets, nanopores, and nanoemulsions are developed to create the nanoscale ITIES for the quantitative electrochemical measurement of ion transfer, electron transfer, and molecular transport across the interface. The nanoscale ITIES serves as an electrochemical nanosensor to enable the selective detection of various ions and molecules as well as high-resolution chemical imaging based on scanning electrochemical microscopy. The powerful nanoelectroanalytical methods will be useful for biological and material applications as illustrated by in situ studies of solid-state nanopores, nuclear pore complexes, living bacteria, and advanced nanoemulsions. These studies provide unprecedented insights into the chemical reactivity of important biological and material systems even at the single nanostructure level. [ABSTRACT FROM AUTHOR]

Interfacial instability, viz., pore formation in the lithium metal anode (LMA) during discharge leading to high impedance, current focusing induced solid–electrolyte (SE) fracture during charging, and formation/behaviour of the solid–electrolyte interphase (SEI), at the anode, is one of the major hurdles in the development of solid‐state batteries (SSBs). Also, understanding cell polarization behaviour at high current density is critical to achieving the goal of fast‐charging battery and electric vehicle. Herein, via in situ electrochemical scanning electron microscopy (SEM) measurements, performed with freshly deposited lithium microelectrodes on transgranularly fractured fresh Li6PS5Cl (LPSCl), the LiǀLPSCl interface kinetics are investigated beyond the linear regime. Even at relatively small overvoltages of a few mV, the LiǀLPSCl interface shows non‐linear kinetics. The interface kinetics possibly involve multiple rate‐limiting processes, i.e., ion transport across the SEI and SE|SEI interfaces, as well as charge transfer across the LiǀSEI interface. The total polarization resistance RP of the microelectrode interface is determined to be ≈ 0.8 Ω cm2. It is further shown that the nanocrystalline lithium microstructure can lead to a stable LiǀSE interface via Coble creep along with uniform stripping. Also, spatially resolved lithium deposition, i.e., at grain surface flaws, grain boundaries, and flaw‐free surfaces, indicates exceptionally high mechanical endurance of flaw‐free surfaces toward cathodic load (>150 mA cm−2). This highlights the prominent role of surface defects in dendrite growth. [ABSTRACT FROM AUTHOR]

The microstructural evolution and corrosion behaviour of railroad flash-butt-welded U71Mn joints and the effect of heat treatment were investigated via scanning electron microscopy and electrochemical measurements. The joint structures were found to mainly comprise pearlite and a few ferrites. The grains became finer and more homogeneous after heat treatment. Additionally, there was a decrease in the corrosion current density (1.71 × 10−5 A cm−2) and increases in the absolute corrosion potential (0.86 mV) and corrosion resistance (1088.83 Ω−1cm2). This was primarily attributed to the fewer Cl− ions at the homogeneous grain boundaries and fewer oxidation reactions on the joints after heat treatment. The findings of this study explain corrosion failure and will guide the development of corrosion-resistant joints for improved railroad quality. [ABSTRACT FROM AUTHOR]

ORR activity and selectivity on native oxide film-covered Ti were quantitatively studied by the reactive tip generation/substrate collection (RTG/SC) mode of scanning electrochemical microscopy (SECM) and further clarified by theoretical calculations. The ORR behavior on Ti is highly film characteristics-dependent. [Display omitted] • ORR activity and selectivity on spontaneous film-covered Ti were studied. • Effects of key factors were quantified by SECM and further clarified by theoretical calculations. • ORR is sensitive to film features, especially on the highly reduced Ti surface. • Hydrogen bonds and/or electrostatic effect improve 4e– selectivity while Cl– suppress reactivity. • This work provides theoretical support and possible guidance for ORR on oxide-covered metals. Unlike noble metals, the oxygen reduction reaction (ORR) behavior on Ti is more complicated due to its spontaneously formed oxide film. This film results in sluggish ORR kinetics and tends to be reduced within ORR potential region, causing the weak and multi-reaction coupled current. Though Ti is being used in chemical and biological fields, its ORR research is still underexplored. We innovatively employed the modified reactive tip generation-substrate collection (RTG/SC) mode of scanning electrochemical microscopy (SECM) with high efficiency of 97.2 % to quantitatively study the effects of film characteristics, solution environment (pH, anion, dissolved oxygen), and applied potential on the ORR activity and selectivity of Ti. Then, density functional theory (DFT) and molecular dynamics (MD) analyses were employed to elucidate its ORR behavior. On highly reduced Ti, film properties dominate ORR behavior with promoted 4e– selectivity. Rapid film regeneration in alkaline/O 2 -saturated conditions inhibits ORR activity. Besides, ORR is sensitive to anion species in neutral solutions while showing enhanced 4e– reduction in alkaline media. All the improved 4e– selectivities originate from the hydrogen bond/electrostatic stabilization effect, while the decayed ORR activity by Cl– arises from the suppressed O 2 adsorption. This work provides theoretical support and possible guidance for ORR research on oxide-covered metals. [ABSTRACT FROM AUTHOR]

Recycling of hardmetal scrap is strategic for critical raw materials recovery. Available recycling processes are polluting and have a large carbon footprint. Attempts to exploit controlled corrosion failed in industrial practice, owing to self-limiting processes. We revisit the corrosion route, in view of gaining the fundamental knowledge enabling high-throughput recovery. We selected the worst-case approach of highly corrosion-resistant CoNiWC-based hardmetal grades and neutral aqueous electrolyte at room temperature. Systematic electrochemical measurements, UV–Vis spectroscopy and SEM microscopy disclosed that, even though there is no hope to overcome the self-limiting corrosion rate, nevertheless, by exploiting the mechanical action of anodic O2 evolution acting precisely at the interface between the residual active material and the corrosion film, the latter can be efficiently removed, periodically reactivating the hardmetal corrosion in a way that results in an ultra-high scrap destruction rate, of interest for real-life industrial processes. [ABSTRACT FROM AUTHOR]

The use of reference electrodes (REs) in lithium‐ion batteries allows enhanced electrochemical analysis of individual electrodes via potential monitoring or electrochemical impedance spectroscopy (EIS). The previous publication presents a concept for a laser‐perforated RE (PRE). Herein, this PRE is applied in ≈60 mAh graphite/NMC811 pouch cells. Despite more than 17% of the electrode surface being covered by the PRE, only negligible capacity differences are observed for charge rates up to 2C compared to cells without PRE. At higher rates up to 5C, the blocking effect is present but stable. Reproducible and plausible anode voltage curves are obtained and the beginning of Li plating is detected. Cell EIS spectra are in good agreement with comparison cells without RE. The impedance spectra of the individual electrodes recorded by the PRE are confirmative and, with one exception, artifact‐free. The results demonstrate that our PRE can be reliably applied for investigating lab‐scale electrode coatings in small pouch cell formats. [ABSTRACT FROM AUTHOR]

The integrity of the solid electrolyte interphase (SEI) formed on the negative electrode of lithium‐ion batteries (LIB) is especially critical for the performance of next‐generation LIBs comprising silicon‐carbon based electrode materials. The protecting character of the SEI is compromised due to volume expansion and shrinking during de/intercalation of Li ions leading to irreversible changes upon long‐term cycling. Scanning electrochemical microscopy (SECM) is proposed as local electrochemical technique to investigate the degradation mechanisms of advanced negative electrodes. The impact of charge/discharge cycling on the SEI properties on Si−C electrodes was investigated, and the sensitivity of SECM successfully reveals inhomogeneities at an early stage of the cycling already at about 5 cycles. Macroscopic EIS measurements and evaluation of the coulombic efficiency may result in misleading interpretations of degradation. SECM is demonstrated to be a powerful and complementary technique for revealing μm‐heterogeneities in the SEI surface reactivity after a few charge/discharge cycles. [ABSTRACT FROM AUTHOR]

Tuning the surface strain of heterogeneous catalysts is recognized as a powerful strategy for tailoring their catalytic activity. However, a clear understanding of the strain effect in electrocatalysis at single‐particle resolution is still lacking. Here, we explore the electrochemical hydrogen evolution reaction (HER) of single Pd octahedra and icosahedra with the same surface bounded {111} crystal facet and similar sizes using scanning electrochemical cell microscopy (SECCM). It is revealed that tensilely strained Pd icosahedra display significantly superior HER electrocatalytic activity. The estimated turnover frequency at −0.87 V vs RHE on Pd icosahedra is about two times higher than that on Pd octahedra. Our single‐particle electrochemistry study using SECCM at Pd nanocrystals unambiguously highlights the importance of tensile strain on electrocatalytic activity and may offer new strategy for understanding the fundamental relationship between surface strain and reactivity. [ABSTRACT FROM AUTHOR]

Flexible conductive electrodes are of enormous significance to the emergence of wearable electronics and the continued growth of modern devices. In this work, we developed versatile electrodes comprising intriguing features of efficient electrochemical energy storage and conversion capabilities. Capacitive active films comprised of reduced graphene oxide conjugated V2O5 nanoribbons coated with poly (3,4-ethylene dioxythiophene), PEDOT conducting polymer, forming ternary composites, i.e., V2O5/PEDOT/rGO on silver nanowires coated transparent substrates as solid-state pseudocapacitors. As constructed symmetric solid-state pseudocapacitor electrodes delivered broad potential window ≥ 1.4 V under different electrolyte environments (aqueous LiCl and organic LiCl/PVA gel), achieved higher areal capacitance ~ 0.6–1.2 mF cm−2 in 0.5 M LiCl organic electrolyte attributed to improved electrode–electrolyte ion interaction and demonstrated higher power and energy density (0.27 μWh cm−2) outperforming previously reported devices. Moreover, kinetic blocking from PEDOT and anchoring capability of rGO nanosheet prevented amphoteric vanadium ions from being dissolved from layered V2O5 nanoribbons contributing unusual stability. Scanning electrochemical microscopy (SECM) provided further insights into electrode kinetics at local level, while quantifying electron (or ion transportation) rate and imaging electroactive site distribution. The decisive differences in electrochemical processes occurring in two different electrolytes are discussed in terms of solvation dynamics of Li-ion containing aqueous and polymer gel electrolytes inducing steric hinderance and corresponded with coupled ion–electron conduction/transport due to effective density of states and wavefunction overlap. [ABSTRACT FROM AUTHOR]

The role of β‐CoOOH crystallographic orientations in catalytic activity for the oxygen evolution reaction (OER) remains elusive. We combine correlative electron backscatter diffraction/scanning electrochemical cell microscopy with X‐ray photoelectron spectroscopy, transmission electron microscopy, and atom probe tomography to establish the structure–activity relationships of various faceted β‐CoOOH formed on a Co microelectrode under OER conditions. We reveal that ≈6 nm β‐CoOOH(011‾ ${\bar{1}}$ 0), grown on [1‾21‾ ${\bar{1}2\bar{1}}$ 0]‐oriented Co, exhibits higher OER activity than ≈3 nm β‐CoOOH(101‾ ${\bar{1}}$ 3) or ≈6 nm β‐CoOOH(0006) formed on [022‾1] ${\bar{2}1]}$ ‐ and [0001]‐oriented Co, respectively. This arises from higher amounts of incorporated hydroxyl ions and more easily reducible CoIII−O sites present in β‐CoOOH(011‾ ${\bar{1}}$ 0) than those in the latter two oxyhydroxide facets. Our correlative multimodal approach shows great promise in linking local activity with atomic‐scale details of structure, thickness and composition of active species, which opens opportunities to design pre‐catalysts with preferred defects that promote the formation of the most active OER species. [ABSTRACT FROM AUTHOR]

Zn metal as one of promising anode materials for aqueous batteries but suffers from disreputable dendrite growth, grievous hydrogen evolution and corrosion. Here, a polycation additive, polydiallyl dimethylammonium chloride (PDD), is introduced to achieve long‐term and highly reversible Zn plating/stripping. Specifically, the PDD can simultaneously regulate the electric fields of electrolyte and Zn/electrolyte interface to improve Zn2+ migration behaviors and guide dominant Zn (002) deposition, which is veritably detected by Zeta potential, Kelvin probe force microscopy and scanning electrochemical microscopy. Moreover, PDD also creates a positive charge‐rich protective outer layer and a N‐rich hybrid inner layer, which accelerates the Zn2+ desolvation during plating process and blocks the direct contact between water molecules and Zn anode. Thereby, the reversibility and long‐term stability of Zn anodes are substantially improved, as certified by a higher average coulombic efficiency of 99.7 % for Zn||Cu cells and 22 times longer life for Zn||Zn cells compared with that of PDD‐free electrolyte. [ABSTRACT FROM AUTHOR]

Bacteria are similar to social organisms that engage in critical interactions with one another, forming spatially structured communities. Despite extensive research on the composition, structure, and communication of bacteria, the mechanisms behind their interactions and biofilm formation are not yet fully understood. To address this issue, scanning probe techniques such as atomic force microscopy (AFM), scanning electrochemical microscopy (SECM), scanning electrochemical cell microscopy (SECCM), and scanning ion-conductance microscopy (SICM) have been utilized to analyze bacteria. This review article focuses on summarizing the use of electrochemical scanning probes for investigating bacteria, including analysis of electroactive metabolites, enzymes, oxygen consumption, ion concentrations, pH values, biofilms, and quorum sensing molecules to provide a better understanding of bacterial interactions and communication. SECM has been combined with other techniques, such as AFM, inverted optical microscopy, SICM, and fluorescence microscopy. This allows a comprehensive study of the surfaces of bacteria while also providing more information on their metabolic activity. In general, the use of scanning probes for the detection of bacteria has shown great promise and has the potential to provide a powerful tool for the study of bacterial physiology and the detection of bacterial infections. [ABSTRACT FROM AUTHOR]

Scanning electrochemical microscopy (SECM) is an attractive technology to in-situ characterize the structural evolution and catalytic performance for various electrocatalysts. However, spatial and temporal resolution coupling are still the obstacles that limit its wide applications. Herein, a new operation mode, Fast Scan mode, was developed by improving the dual-pass scan mode, designing novel hardware structure, and employing thermal drift calibration software to achieve a high spatial and temporal resolution simultaneously. The temporal speed can achieve 4 Hz for a high spatial resolution (less than 30 nm) image. This operation mode was employed to dynamically track the phase transition process of molybdenum disulfide (MoS2) over time and characterize the hydrogen evolution reaction (HER) catalytic activity on the edge of semiconducting MoS2 quantitatively while minimizing the diffusional broadening effect and total amount of catalytic products generated above the surface. This new approach should be useful for in-situ tracking dynamic electrochemical processes, establishing the structure-activity relationship for structural complex electrocatalysts, and offering a strategy for high-speed scanning with other electrochemical imaging techniques. [ABSTRACT FROM AUTHOR]

MXene, a family of two-dimensional (2D) transition metal carbides and nitrides, has intriguing electrochemical energy storage and electrocatalysis applications. Introducing the electronic metal-support interaction (EMSI) effect is one effective strategy to optimize the catalytic efficiency for MXene-based composites. However, most of the studies concentrate on optimizing the performance of metals rather than supported substrates by using this strategy. In this work, we mainly investigate the influence of an EMSI effect on the performance of the supported substrate (Ti3C2Tx MXene). Detailed scanning electrochemical microscopy and numerical simulations results reveal that the charge distribution on the Ti3C2Tx basal plane (approximate 100 nm-radius) surrounding Au nanoparticles (20 nm-radius) was significantly enhanced as a result of —O being the majority surface functional group on Ti3C2Tx that was attached to Au nanoparticle, and the related hydrogen evolution reaction (HER) activity was much better than that of the unaffected Ti3C2Tx basal plane, which even can be comparable to that of Au. This finding will be helpful for designing new strategies to enhance the overall catalytic performance of various MXene-based composites. [ABSTRACT FROM AUTHOR]

We present the results of studying, mapping, and bathymetric profiling of the sea bottom relief from the research vessel Noosfera and the map of the Argentine Islands' underwater relief based on current data. The paper contains a brief description of the material, granulometric (grain size analyses), and mineral composition of bottom sediments collected during the expedition in deep and shallow sites, as well as an analysis of sedimentation conditions in the region. We also provide the results of a study of the taxonomical and ecological diversity of siliceous microfossils of bottom sediments in Penola Strait; the material is illustrated with a table of images of diatoms studied using the scanning electron microscope. The fieldwork methods on the research vessel and in the laboratory and analytic works are described. [ABSTRACT FROM AUTHOR]

Optical tunability and repeatability are essential in fabricating optoelectronic devices from waveguides to Bragg gratings (BGs) for high‐energy, high‐power, mode‐locking, and sensing applications. For this purpose, a controlled adjustment in the optical properties, including the refractive index of the deposited nanolayers, becomes critical. This study reveals that silicon oxynitride (SiON) doping into silicon (Si) offers a new way for the preparation of novel Si‐based devices with an emphasis on the BGs for filtering a particular portion of an electromagnetic spectrum, including the wavelengths of 800, 976, 1550, and 1840 nm. Control on the incident angle dependence of the BGs is demonstrated at Watt‐level for the wavelength of 976 nm. Amorphous SiON‐doped Si layers on alternating SiO2 can be synthesized on bulk substrates and different optical fibers at relatively low temperatures with wide and narrow bandwidths. The high reflectivity of the novel Si‐based BGs reveals over −22 dB reflection using typical optical fibers, including standardsingle‐mode fibers and high‐birefringent polarization‐maintaining (PM) fibers. The polarized transmission measurement over the BG on the PMfiber shows the BGs do not deteriorate the PM properties, strongly yielding a beat length of 1.68 mm and birefringence of 9.2 × 10−4 at the telecom C band. [ABSTRACT FROM AUTHOR]

Recently, non‐Faradaic effects were used to modify the electronic structure and reactivity of electrode‐bound species. We hypothesize that these electrostatic perturbations could influence the chemical reactivity of electrolyte species near an electrode in the absence of Faradaic electron transfer. A prime example of non‐Faradaic effects is acid‐base dissociation near an interface. Here, we probed the near‐electrode dissociation of N‐heterocycle‐BF3 Lewis adducts upon electrode polarization, well outside of the redox potential window of the adducts. Using scanning electrochemical microscopy and confocal fluorescence spectroscopy, we detected a potential‐dependent depletion of the adduct near the electrode. We propose an electro‐inductive effect where a more positive potential leads to electron withdrawal on the N‐heterocycle. This study takes a step forward in the use of electrostatics at electrochemical interfaces for field‐driven electrocatalytic and electro‐synthetic processes. [ABSTRACT FROM AUTHOR]

The kinetics of oxide layer formation on surface of Ti6Al4V alloy samples is a very important property especially if their application as medical implants is planned. Damaged protective surface layer usually heals in ambient condition however; during the self‐healing process toxic species can get into the surrounding living tissue. In our experiment the kinetics of the healing process proceeding at 3D printed alloy surface has been studied using electrochemical methods, among them scanning electrochemical microscopy. More than 40 min. time period was found long enough for total healing. [ABSTRACT FROM AUTHOR]

Scanning electrochemical microscopy (SECM) is a versatile scanning probe technique that allows monitoring of a plethora of electrochemical reactions on a highly resolved local scale. SECM in combination with atomic force microscopy (AFM) is particularly well suited to acquire electrochemical data correlated to sample topography, elasticity, and adhesion, respectively. The resolution achievable in SECM depends critically on the properties of the probe acting as an electrochemical sensor, i.e., the working electrode, which is scanned over the sample. Hence, the development of SECM probes received much attention in recent years. However, for the operation and performance of SECM, the fluid cell and the three-electrode setup are also of paramount importance. These two aspects received much less attention so far. Here, we present a novel approach to the universal implementation of a three-electrode setup for SECM in practically any fluid cell. The integration of all three electrodes (working, counter, and reference) near the cantilever provides many advantages, such as the usage of conventional AFM fluid cells also for SECM or enables the measurement in liquid drops. Moreover, the other electrodes become easily exchangeable as they are combined with the cantilever substrate. Thereby, the handling is improved significantly. We demonstrated that high-resolution SECM, i.e., resolving features smaller than 250 nm in the electrochemical signal, could be achieved with the new setup and that the electrochemical performance was equivalent to the one obtained with macroscopic electrodes. [ABSTRACT FROM AUTHOR]

Gas evolution in high‐energy Li‐ion batteries remains a pervasive problem for a multitude of chemistries, jeopardizing the electrochemical performance and safety for consumers of electric vehicles. Many electrode–electrolyte degradation processes evolve gasses that may be detected in‐situ with online electrochemical mass spectrometry (OEMS). In this work, details are provided for the setup and validation of an OEMS system that operates well under lean and volatile electrolyte conditions. Quite notably, the OEMS cells with only 40 µL of electrolyte and intermittent headspace sampling exhibit comparable electrochemical performance to flooded coin‐cells. It is demonstrated that the onset time, shape, and magnitude of the gas evolution profiles calculated from mass spectrometer measurements match well to a known pressure reference through the use of an empirically determined fraction of removal. The off‐gassing characteristics from a set of layered‐oxide materials, NMC532, NMC811, and LNO, are used to further validate the OEMS setup against the literature. It is shown that many of the features present in the OEMS curves for equivalent systems from other groups are captured by this OEMS system. At an upper cut‐off voltage of 4.4 V, LNO exhibits an intense release of CO2, O2, and CO gas relative to NMC532 and NMC811. [ABSTRACT FROM AUTHOR]

Cathodic electrical stimulation has previously been studied for both the augmentation of bone healing as well as the treatment of implant associated infections. One of the proposed mechanisms of both of these effects is the electrochemical generation of hydrogen peroxide during the oxygen reduction reaction. Titanium and 316L stainless steel are commonly used as implants and surgical hardware in orthopedic applications. The oxygen reduction reaction has been shown to be complex on passivated metal electrodes such as these. Therefore, the exact potential ranges of H2O2 generation on these materials in physiologically relevant media are not fully characterized. This study employed Rotating Ring-Disk Electrode techniques as well as Scanning Electrochemical Microscopy methods to characterize the electrochemical generation of H2O2 on titanium and 316L stainless steel. [ABSTRACT FROM AUTHOR]

The integration of bacteriophages, a particular class of viruses that specifically infect bacteria and archaea, in biosensors for the monitoring of pathogens in foods and beverages is highly desirable. To this end, an increasing focus has been set on the exploration of covalent and physical methods for the immobilization of phages on solid surfaces. This work investigates the electrostatic assembly of tailed phages, specifically anti-Listeria monocytogenes P100 phages, on an ultrathin self-assembled monolayer (SAM) of 11-amino-1-undecanethiol (AUT). The cationic properties of AUT may allow for the electrostatic capture of P100 in a capsid-down fashion, thereby exposing the specific receptor-binding proteins on their tails to the corresponding pathogens in the analytical samples. The morphology and charge transfer behavior of the assembled films were studied with atomic force microscopy, scanning electron microscopy and electrochemical techniques. These methods provided valuable insights into the orientation of the phages and the relevant role of the pH. Biological plaque assays revealed that the immobilized phages remain active towards the target bacterium. Overall, this research portrays SAMs of amino-akylthiols as a valid platform for the oriented immobilization of bacteriophages on surfaces for electroanalytical purposes. [ABSTRACT FROM AUTHOR]

In this paper, the applicability of Ti6Al7Nb as a more biocompatible alternative for bone and dental implants than Ti6Al4V and pure titanium in terms of corrosion resistance and electrochemical inertness is investigated. The chemical inertness and corrosion resistance of the Ti6Al7Nb biomaterial were characterized by a multi-scale electrochemical approach during immersion in simulated physiological environments at 37 °C comparing its behavior to that of c.p. Ti, Ti6Al4V, and stainless steel. The establishment of a passive regime for Ti6Al7Nb results from the formation of a thin layer of metal oxide on the surface of the material which prevents the action of aggressive species in the physiological medium from direct reaction with the bulk of the alloy. Conventional electrochemical methods such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) provide quantified information on the surface film resistance and its stability domain that encompasses the potential range experienced in the human body; unfortunately, these methods only provide an average estimate of the exposed surface because they lack spatial resolution. Although local physiological environments of the human body are usually simulated using different artificial physiological solutions, and changes in the electrochemical response of a metallic material are observed in each case, similar corrosion resistances have been obtained for Ti6Al7Nb in Hank's and Ringer's solutions after one week of immersion (with a corrosion resistance of the order of MΩ cm2). Additionally, scanning electrochemical microscopy (SECM) provides in situ chemical images of reactive metal and passive dielectric surfaces to assess localized corrosion phenomena. In this way, it was observed that Ti6Al7Nb exhibits a high corrosion resistance consistent with a fairly stable passive regime that prevents the electron transfer reactions necessary to sustain the metal dissolution of the bulk biomaterial. Our results support the proposition of this alloy as an efficient alternative to Ti6Al4V for biomaterial applications. [ABSTRACT FROM AUTHOR]

Iron phthalocyanine‐based polymers (PFePc) are attractive noble‐metal‐free candidates for catalyzing oxygen reduction reaction (ORR). However, the low site‐exposure degree and poor electrical conductivity of bulk PFePc restricted their practical applications. Herein, laminar PFePc nanosheets covalently and longitudinally linked to graphene (3D‐G‐PFePc) was prepared. Such structural engineering qualifies 3D‐G‐PFePc with high site utilization and rapid mass transfer. Thence, 3D‐G‐PFePc demonstrates efficient ORR performance with a high specific activity of 69.31 μA cm−2, a high mass activity of 81.88 A g−1, and a high turnover frequency of 0.93 e s−1 site−1 at 0.90 V vs. reversible hydrogen electrode in O2‐saturated 0.1 M KOH, outperforming the lamellar PFePc wrapped graphene counterpart. Systematic electrochemical analyses integrating variable‐frequency square wave voltammetry and in situ scanning electrochemical microscopy further underline the rapid kinetics of 3D‐G‐PFePc towards ORR. [ABSTRACT FROM AUTHOR]

Heterogeneous light‐driven catalysis is a cornerstone of sustainable energy conversion. Most catalytic studies focus on bulk analyses of the hydrogen and oxygen evolved, which impede the correlation of matrix heterogeneities, molecular features, and bulk reactivity. Here, we report studies of a heterogenized catalyst/photosensitizer system using a polyoxometalate water oxidation catalyst and a model, molecular photosensitizer that were co‐immobilized within a nanoporous block copolymer membrane. Via operando scanning electrochemical microscopy (SECM), light‐induced oxygen evolution was determined using sodium peroxodisulfate (Na2S2O8) as sacrificial electron acceptor. Ex situ element analyses provided spatially resolved information on the local concentration and distribution of the molecular components. Infrared attenuated total reflection (IR‐ATR) studies of the modified membranes showed no degradation of the water oxidation catalyst under the reported light‐driven conditions. [ABSTRACT FROM AUTHOR]

The dynamic restructuring of Cu surfaces in electroreduction conditions is of fundamental interest in electrocatalysis. We decode the structural dynamics of a Cu(111) electrode under reduction conditions by joint first‐principles calculations and operando electrochemical scanning tunneling microscopy (ECSTM) experiments. Combining global optimization and grand canonical density functional theory, we unravel the potential‐ and pH‐dependent restructuring of Cu(111) in acidic electrolyte. At reductive potential, Cu(111) is covered by a high density of H atoms and, below a threshold potential, Cu adatoms are formed on the surface in a (4×4) superstructure, a restructuring unfavorable in vacuum. The strong H adsorption is the driving force for the restructuring, itself induced by the electrode potential. On the restructured surface, barriers for hydrogen evolution reaction steps are low. Restructuring in electroreduction conditions creates highly active Cu adatom sites not present on Cu(111). [ABSTRACT FROM AUTHOR]

The formation of metal nanoparticles (NPs) on surfaces by electrodeposition is of significant interest, particularly with a view to understand the early stages of nucleation and growth. Here, the combination of scanning electrochemical cell microscopy (SECCM) and interference reflection microscopy (IRM) is demonstrated to be a compelling approach for real‐time monitoring of NP dynamics within the SECCM meniscus‐electrode wetted area, through synchronous monitoring in the millisecond range of the electrochemical and optical signatures. Diffraction‐limited entities, undergoing phase changes at the electrode substrate, are readily highlighted and tracked in time, including the onset time for the appearance of NPs and their movement over time. The results strongly implicate the rapid formation, surface diffusion and aggregation of smaller entities (not detectable optically) to produce the larger electrodeposited NPs. By applying SECCM tips of different size, it is also possible to understand how the wetted area (meniscus size) plays a key role in the number of NPs formed, with small tip sizes allowing the formation of single NPs. The SECCM‐IRM approach is expected to be a powerful platform for the study of myriad phase‐formation processes at the nanoscale, particularly by drawing on the possibility of making hundreds or thousands of measurements in fresh surface locations through SECCM technology. [ABSTRACT FROM AUTHOR]

Tyrosine (l-Tyr), which is found in basic foods, is a nonessential amino acid and a metabolite of phenylalanine, has many roles in human metabolism, and is important in maintaining nutritional balance. In this study, an electrochemical method has been presented to determine low levels of l-Tyr using an electrochemically treated pencil graphite electrode (EPGE) via overoxidation of graphite surface and intercalation of Li+ ions into graphite by cyclic voltammetry in the potential range between −0.3 and 2.0 V. Characterization studies of the EPGEs were carried out using scanning electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, Fourier transform infrared spectroscopy, atomic force microscopy, and cyclic voltammetry. The determination of l-Tyr was performed by differential pulse voltammetry, and the investigation of electrochemical properties of l-Tyr was conducted by cyclic voltammetry. The results showed that the EPGE presents high electrocatalytic performance and has a low detection limit (0.12 μM) for determining l-Tyr with a wide linear range from 1.0 to 500 μM. The selectivity of prepared EPGE was investigated in the presence of organic species. The determination of l-Try was performed in yoghurt and milk samples and good results were obtained with recoveries between 95.7% and 103.1%. Stability and repeatability studies further demonstrate the applicability of the sensor. [ABSTRACT FROM AUTHOR]

In this study, the formation and evolution of a corrosion product film on a 304 stainless steel exposed to an HCl pickling solution containing H2O2 were evaluated. Electrochemical polarization, spectroscopy, and characterization techniques including scanning electron microscopy, energy-dispersive x-ray spectroscopy, confocal laser scanning microscopy, and x-ray photoelectron spectroscopy were employed to investigate the characteristics of the corrosion product film and its effect on the corrosion of the stainless steel. The composition and structure of the corrosion product films were governed by the chemical oxidation of H2O2, which was dependent on the H2O2 concentration. The formation of a loosened CrCl3, FeCl2, and FeCl3 salt film occurs in the presence of 0.05-M H2O2. With a higher H2O2 concentration (0.15–0.60 M), the Fenton's reaction creates an environment for the production of chromium oxides and hydroxides. A compact film consisting of Cr(OH)3 and Cr2O3 covers the stainless steel. The dissolution of metal is then governed by the random availability of cation vacancies at the metal/film interface rather than the lattice structure of the metal, which contributes to the anodic brightening of the stainless steel. The compact film can dissolve in the HCl–H2O2 solution and transform into chloride salts again. Once the compact film breaks without self-repair, it causes a local attack at grain boundaries of the stainless steel. [ABSTRACT FROM AUTHOR]

Polymeric coatings have long been utilized in the shipping industry to protect the metallic equipment against corrosion. Multifunctional 2-amino-5-(methylthio)-1,3,4-thiadiazole (AMTTD) modified with zirconium carbide (ZrC) (AMTTD/ZrC) nanoparticles were synthesized by solution intercalation method, and the influence of adding AMTTD/ZrC nanoparticles within neat epoxy (EP) coating on steel structures was investigated for its hydrophobic, mechanical, and electrochemical properties in seawater. The electrochemical impedance spectroscopy and scanning electrochemical microscopy (SECM) techniques were utilized to investigate the protective properties of the investigated coatings. The coating resistance of the EP-AMTTD/ZrC-coated steel was found to be 6096.79 kΩ cm2 even after 360 h of exposure to seawater. The coating resistance of EP-AMTTD/ZrC nanocomposite is found to be more than 40% greater than that of EP coating. In comparison to EP-coated steel (19.8 nA), the corrosion current density of EP-AMTTD/ZrC composite-coated steel generated by SECM method was 1.8 nA. The surface morphological studies such as field emission-scanning electron microscopy with energy-dispersive x-ray spectroscopy (FE-SEM/EDX), and x-ray diffraction analysis were carried out to examine the nature of the corrosion products. The water repellent property of the coatings was characterized by water contact angle (WCA) measurement. The newly developed EP-AMTTD/ZrC nanocomposite coating had increased hydrophobic characteristics (WCA: 143°). The adhesion strength of EP- AMTTD/ZrC nanocomposite coatings is found to be 13.2 MPa. Therefore, the compatibility of EP, AMTTD, and ZrC nanoparticles was established by superior hydrophobicity and improved corrosion protection and enhanced mechanical properties. Thus, the EP-AMTTD/ZrC nanocomposite coating could be employed as the vital coating materials in a variety of industrial applications. [ABSTRACT FROM AUTHOR]

Newly synthesized 3-amino-1,2,4-triazole-5-thiol (ATT) functionalized Al2O3-ZnO nanoparticles were added to epoxy resin (EP). The anticorrosion properties of newly synthesised formulations like EP/Al2O3-ZnO and EP-ATT/Al2O3-ZnO nanocomposite coated steel samples were investigated electrochemically using scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS). In natural seawater, EIS experiments indicated outstanding protective behaviour for the EP-ATT/Al O3-ZnO coated steel. The EP-ATT/Al2O3-ZnO nanocomposite coating resistance was reported to be 2110.44 kΩ·cm², whereas EP/Al2O3-ZnO coating (1730.45 kΩ·cm²) and pure epoxy coating (61.21 kΩ·cm²) had lesser coating resistance. The coating resistance of EP-ATT/Al2O3-ZnO nanocomposite was found to be more than 34% greater than that of PU coating. The measured current by SECM analysis over the EP-ATT/Al2O3-ZnO nanocomposite coating was very low (1.6 nA) compared to EP/Al2O3-ZnO (3.7 nA) and pure epoxy coated steel (5.9 nA). The surface morphological studies of the coated steel by SEM/EDX analysis and X-ray diffraction (XRD) analysis revealed that the Al2O3-ZnO nanoparticles were enriched at the corrosion products which prevented corrosion initiation processes. The peel strength of the EP-ATT/Al2O3-ZnO nanocomposite film was found to be 982 ± 13 N/cm when the concentration of ATT/Al2O3-ZnO nanoparticles was 2 wt.%. Moreover, the resultant EP-ATT/Al2O3-ZnO formulation exhibited an excellent hydrophobic behaviour (WCA: 117°). Therefore, it was concluded from the electrochemical and mechanical investigation that the newly synthesized EP-ATT/Al2O3-ZnO nanocomposite provided an excellent barrier and mechanical properties due to the addition of ATT/Al2O3-ZnO nanoparticles to the epoxy resin which prevented the degradation of materials and helped to prolong the life of the coated steel. [ABSTRACT FROM AUTHOR]

The interactions of zopiclone with electrochemically reduced graphene oxide (rGO) modified electrode were examined. A comparison of GC/rGO and glassy carbon electrode (GC) by electrochemical impedance spectroscopy and scanning electrochemical microscopy (SECM) shows that the modified surface is much less conductive than GC. The role of rGO is to act as a site of specific adsorption of the analyte. Molecular dynamics showed that the monoanionic form of zopiclone presents more interactions with defects of rGO. The analytical methodology allowed obtaining a linearity of 10–130 μg L−1, with a limit of detection of 2.14 μg L−1 using SWAdSV at pH 10.0. [ABSTRACT FROM AUTHOR]

In this article, poly(1,2‐diaminoanthraquinone) (pDAAQ) and poly(1,5‐diaminonaphthalene) (pDAN) were electrochemically deposited layer by layer on a glassy carbon electrode (GCE) to generate pDAAQ/pDAN@GCE and pDAN/pDAAQ@GCE composite electrodes, respectively. The morphology and characteristics of the modified electrodes were investigated via electrochemical impedance spectroscopy)EIS), Fourier transform infrared spectroscopy (FT‐IR), and scanning electron microscopy)SEM). The obtained results reveal the outstanding performance of the pDAN/pDAAQ@GCE electrode for electrochemical nitrite sensing where pDAAQ plays a vital role as the inner layer. Cyclic voltammetry (CV), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV) measurements revealed that the oxidation peak current of nitrite was proportional to its concentration. The best LSV results were obtained in a concentration range of 10–150 μM, with a limit of detection of 1.2 μM. Furthermore, the pDAN/pDAAQ@GCE composite electrode was used to determine nitrite ions in real water samples with good results. [ABSTRACT FROM AUTHOR]

A nanosecond pulsed fiber laser was used to modify the surface of 304 stainless steel. The compactness, microstructure, chemical composition, and corrosion resistance of the stainless steel passive film were observed by the blue dot detection method, scanning electron microscopy, x‐ray photoelectron spectroscopy, and electrochemical methods. The influence of different laser fluences on the stability and corrosion resistance of the stainless steel passive film was studied. The results show that with increasing laser fluence, the discoloration reaction time of the stainless steel surface increases first and then decreases, while the surface roughness decreases first and then increases. When the laser fluence is lower than 11.19 J/cm2, a compact and uniform passive film is formed. When the laser fluence is larger than this value, the stainless steel substrate is prone to secondary corrosion. Chromium oxides are enriched in the passive film, and the anodic dissolution rate decreases, which promotes a positive shift in the corrosion potential of the stainless steel, decreases the corrosion current density and increases the polarization resistance and the corrosion resistance. The surface corrosion resistance is thus significantly improved. [ABSTRACT FROM AUTHOR]

Photo-/electrochemical water splitting can be a suitable method to produce "green" hydrogen and oxygen by utilizing renewable energy or even direct sunlight. In order to carry out photoelectrochemical (PEC) water splitting, a photoanode based on transition metal oxides, which absorbs photons and produces photoexcited electron–hole pairs, is needed. The positively charged holes can then participate in the water oxidation reaction. Meanwhile, a cathodic hydrogen evolution reaction (HER) can occur more efficiently with electrocatalytic materials that enhance the adsorption of H+, such as MoS2. In this study, it was shown that WO3/MoSx heterostructured materials can be synthesized by an electrochemical method called plasma electrolytic oxidation (PEO). During this process, many micro-breakdowns of the oxide layer occur, causing ionization of the oxide and electrolyte. The ionized mixture then cools and solidifies, resulting in crystalline WO3 with incorporated MoSx. The surface and cross-sectional morphology were characterized by SEM-FIB, and the coatings could reach up to 3.48 μm thickness. Inclusion of MoSx was confirmed by EDX as well as XPS. Synthesis conditions were found to have an influence on the band gap, with the lowest value being 2.38 eV. Scanning electrochemical microscopy was used to map the local HER activity and correlate the activity hotspots to MoSx's content and surface topography. The bifunctional catalyst based on a WO3/MoSx heterostructure was evaluated for PEC and HER water-splitting activities. As a photoanode, it could reach up to 6% photon conversion efficiency. For HER in acidic media, a Tafel slope of 42.6 mV·dec−1 can be reached. [ABSTRACT FROM AUTHOR]

The challenges associated to oxygen reduction reaction (ORR) electrocatalysis are undoubtedly the most intricate impediments to solve regarding fuel cell vehicle (FCV) commercialization, mainly due to the complexity of this reaction and the scarcity of the required electrocatalysts. The synthesis of non-precious electrocatalysts with high intrinsic selectivity is indeed crucial in this field, but the methodology utilized to come to selectivity conclusions is undeniably equally important. In this work, we demonstrate how the higher required electrode loadings of a Fe-N-MWCNT catalyst in a rotating ring disc electrode (RRDE) prevent access to all of the peroxide produced by the catalyst during ORR. Via a spraying technique, much smaller amounts of the same catalyst were deposited on a flat boron-doped diamond (BDD) and their loading was determined meticulously by atomic force microscopy (AFM). These ultra-low loadings were investigated using scanning electrochemical microscopy (SECM), which revealed higher peroxide production and lower selectivity. This finding may have crucial implications for future ORR investigations in the laboratory, considering the harmful effect peroxide has on the catalyst.

The effect of carbon onions or onionlike carbons (OLCs) as a dopant on the supercapacitive properties of titanium carbide MXene (Ti2C) has been studied. The materials were characterized using x-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and electrochemical techniques, including cyclic voltammetry, constant current charge/discharge, and electrochemical impedance spectroscopy. It was found that the introduction of OLCs into the layered MXene structure increases the long-term cycling stability of the material from ∼80% to >95%. It was also found to increase the supercapacitance of MXene in the 5% quantity from ca. 104 to 148 F/g but decreased the supercapacitance in the 10% quantity from ca. 104 to 92 F/g. The power and energy density improved in the 5% OLC-doped sample compared to the pristine sample for current densities between 0.5 and 5 A/g. Overall, this study showcased the unique ability of OLCs to improve the electrochemical performance of a Ti2C-based supercapacitor. [ABSTRACT FROM AUTHOR]

The effect of carbon onions or onionlike carbons (OLCs) as a dopant on the supercapacitive properties of titanium carbide MXene (Ti2C) has been studied. The materials were characterized using x-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and electrochemical techniques, including cyclic voltammetry, constant current charge/discharge, and electrochemical impedance spectroscopy. It was found that the introduction of OLCs into the layered MXene structure increases the long-term cycling stability of the material from ∼80% to >95%. It was also found to increase the supercapacitance of MXene in the 5% quantity from ca. 104 to 148 F/g but decreased the supercapacitance in the 10% quantity from ca. 104 to 92 F/g. The power and energy density improved in the 5% OLC-doped sample compared to the pristine sample for current densities between 0.5 and 5 A/g. Overall, this study showcased the unique ability of OLCs to improve the electrochemical performance of a Ti2C-based supercapacitor. [ABSTRACT FROM AUTHOR]

Several in-situ electrochemical approaches have been developed for performing a localized photoelectrochemical investigation of the photoanode. One of the techniques is scanning electrochemical microscopy (SECM), which probes local heterogeneous reaction kinetics and fluxes of generated species. In traditional SECM analysis of photocatalysts, evaluation of the influence of radiation on the rate of studied reaction requires an additional dark background experiment. Here, using SECM and an inverted optical microscope, we demonstrate the determination of O2 flux caused by light-driven photoelectrocatalytic water splitting. Photocatalytic signal and dark background are recorded in a single SECM image. We used an indium tin oxide electrode modified with hematite (α-Fe2O3) by electrodeposition as a model sample. The light-driven flux of oxygen is calculated by analysis of SECM image recorded in substrate generation/tip collection mode. In photoelectrochemistry, the qualitative and quantitative knowledge of oxygen evolution will open new doors for understanding the local effects of dopants and hole scavengers in a straightforward and conventional manner. [ABSTRACT FROM AUTHOR]

A challenging task is to promote Ru atom economy and simultaneously alleviate Ru dissolution during the hydrogen evolution reaction (HER) process. Herein, Ru nanograins (≈1.7 nm in size) uniformly grown on 1T‐MoS2 lace‐decorated Ti3C2Tx MXene sheets (Ru@1T‐MoS2‐MXene) are successfully synthesized with three types of interfaces (Ru/MoS2, Ru/MXene, and MoS2/MXene). It gives high mass activity of 0.79 mA µgRu−1 at an overpotential of 100 mV, which is ≈36 times that of Ru NPs. It also has a much smaller Ru dissolution rate (9 ng h−1), accounting for 22% of the rate for Ru NPs. Electrochemical tests, scanning electrochemical microscopy measurements combined with DFT calculations disclose the role of triple interface optimization in improved activity and stability. First, 2D MoS2 and MXene can well disperse and stabilize Ru grains, giving larger electrochemical active area. Then, Ru/MoS2 interfaces weakening H* adsorption energy and Ru/MXene interfaces enhancing electrical conductivity, can efficiently improve the activity. Next, MoS2/MXene interfaces can protect MXene sheet edges from oxidation and keep 1T‐MoS2 phase stability during the long‐term catalytic process. Meanwhile, Ru@1T‐MoS2‐MXene also displays superior activity and stability in neutral and alkaline media. This work provides a multiple‐interface optimization route to develop high‐efficiency and durable pH‐universal Ru‐based HER electrocatalysts. [ABSTRACT FROM AUTHOR]

In the present world, the high energy demand rapidly depletes existing fossil fuel reserves, urging the necessity to harvest energy from clean and renewable resources. In this study, the use of a triboelectric nanogenerator (TENG) is shown beyond the conventional practice of use in self‐powered electronics, to the production of green hydrogen from renewable mechanical energy. For the first time the use of a magnetic covalent organic framework composite as positive triboelectric material for a contact‐separation mode TENG (CS‐TENG) in which MXene incorporated polydimethylsiloxane (PDMS) film serves as negative triboelectric material, is demonstrated. A facile way of incorporating micropatterns on the surface of PDMS/MXene film is shown utilizing the advantages of 3D printing technology. The CS‐TENG harvests energy from simple mechanical actions such as human handclapping and toe‐tapping. The energy from such low‐scale mechanical actions is applied for water electrolysis. Scanning electrochemical microscopy is employed to confirm the evolution of hydrogen and oxygen by the harvested electrical energy from mechanical actions. This research is expected to pave the way for producing green hydrogen anywhere, by utilizing the mechanical energy from nature such as raindrops, wind, and the movement of vehicles. [ABSTRACT FROM AUTHOR]

Lithium metal is one of the most promising anode materials for lithium-ion batteries; however, lithium dendrite growth hinders its large-scale development. So far, the dendrite formation mechanism is unclear. Herein, the dynamic evolution of lithium deposition in etheryl-based and ethylene carbonate (EC)-based electrolytes was obtained by combining an in situ electrochemical atomic force microscope (EC-AFM) with an electrochemical workstation. Three growth modes of lithium particles are proposed: preferential, merged, and independent growth. In addition, a lithium deposition schematic is proposed to clearly describe the morphological changes in lithium deposition. This schematic shows the process of lithium deposition, thus providing a theoretical basis for solving the problem of lithium dendrite growth. [ABSTRACT FROM AUTHOR]

Carbon‐based nanomaterials are renowned for their exceptional properties, making them propitious candidates for oxygen reduction reaction (ORR) electrocatalysis. However, their intrinsic activity is often challenging to investigate unambiguously with conventional methodologies due to the inherent complexities of such systems and the material itself. Zooming into the material and gaining electrochemical information with high resolution is a way to get rid of many experimental factors that influence the catalytic activity in macro‐scale measurements. Herein, we employ nano‐scale scanning electrochemical cell microscopy (SECCM) to investigate individual catalyst agglomerates with and without Nafion content. The intrinsic ORR activity of the catalyst was unravelled by using a unique approach of normalizing the data of all measured points by their distinctive electrochemical surface area (ECSA). When coupling with scanning electron microscopy (SEM), the structure and morphology of the catalytically active agglomerates were visualized. [ABSTRACT FROM AUTHOR]

Fingerprints have long been the gold standard for personal identification in forensic science. However, realizing the high-resolution enhancement of eccrine LFPs is difficult using the traditional methods and the label-free detection of fingerprint residue information is also challenging. Herein, we propose two enhancement strategies for LFPs on PVDF membrane (LFPs/PVDF) using blue-black ink staining and scanning electrochemical microscopy (SECM). The blue-black ink staining method was used for the first time to develop three types (sebaceous, natural and eccrine) of LFPs/PVDF based on the difference in wettability between the fingerprint residues and PVDF membrane. The enhanced fingerprints clearly displayed levels 1–3 features with high contrast and low background interference. Furthermore, we achieved chemical imaging of the LFP/PVDF samples, where their possible visualization mechanisms were ascribed to the electrochemical reactivity of squalene and difference in wettability between the LFP and PVDF membrane, which was first proposed and investigated by SECM imaging and water contact angle (WCA) measurements, respectively. Significantly, SECM imaging not only provided fingerprint patterns without any labelling but also revealed the spatial distribution information of squalene in LFPs simultaneously. In addition, it was also demonstrated that LFPs deposited on various surfaces were first successfully transferred to the PVDF membrane, and then further developed with both methods, making them general for personal identity-related applications. Taken together, the blue-black ink staining method can easily and quickly obtain level 3 features of LFPs/PVDF and the SECM approach can non-invasively image the topography and chemical information of LFPs/PVDF, and thus they can be potentially selected according to various requirements in forensic scenarios. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) is considered as one of the most promising non‐noble‐metal catalysts for hydrogen evolution reaction (HER). To achieve practical application, introducing sulfur (S) vacancies on the inert basal plane of MoS2 is a widely accepted strategy to improve its HER activity. However, probing active sites at the nanoscale and quantitatively analyzing the related electrocatalytic activity in electrolyte aqueous solution are still great challenges. In this work, utilizing high‐resolution scanning electrochemical microscopy, optimized electrodes and newly designed thermal drift calibration software, the HER activity of the S vacancies on an MoS2 inert surface is in situ imaged with less than 20‐nm‐radius sensitivity and the HER kinetic data for S vacancies, including Tafel plot and onset potential, are quantitatively measured. Additionally, the stability of S vacancies over the wide range of pH 0−13 is investigated. This study provides a viable strategy for obtaining the catalytic kinetics of nanoscale active sites on structurally complex electrocatalysts and evaluating the stability of defects in different environments for 2D material‐based catalysts. [ABSTRACT FROM AUTHOR]

This review article outlines the set of observations and findings from some previous publications that addressed the different techniques used for understanding and evaluating metallic corrosion and its retardation by using different inhibitors. The main emphasis is on the different electrochemical characterization techniques and surface analysis methods used for studying corrosion inhibition. A brief about polarization, electrochemical noise, electrochemical frequency modulation, impedance study for electrochemical characterization techniques and contact angle, scanning electrochemical microscopy, atomic force microscopy, and scanning electron microscopy methods, x-ray photoelectron spectroscopy, etc. are included for a better understanding of corrosion inhibition phenomenon. The literature suggests that corrosion of metals and alloys is effectively controlled by the use of inhibitors having heteroatoms such as nitrogen, oxygen, or sulfur. In this article, the papers from the last sixteen years i.e., from 1996 to 2021 are considered to get an insight into current methods for retarding corrosion. General introduction, mechanisms of corrosion along with factors affecting corrosion has also been described in the present article. Data collected in this review will be advantageous for researchers to get an idea about the basics and the recent techniques used in corrosion study. [ABSTRACT FROM AUTHOR]

Myocardial fibrosis progression and imbalanced redox state are closely associated with increased extracellular matrix (ECM) stiffness. Candesartan (CAN), an angiotensin II (Ang II) receptor inhibitor, has shown promising anti-fibrosis and antioxidant efficacy in previous cardiovascular disease studies. However, the effect of ECM stiffness on CAN efficacy remains elusive. In this study, we constructed rat models with three different degrees of myocardial fibrosis and treated them with CAN, and then characterized the stiffness, cardiac function, and NADPH oxidase-2 (NOX2) expression of the myocardial tissues. Based on the obtained stiffness of myocardial tissues, we used polyacrylamide (PA) gels with three different stiffness to mimic the ECM stiffness of cardiac fibroblasts (CFs) at the early, middle, and late stages of myocardial fibrosis as the cell culture substrates and then constructed CFs mechanical microenvironment models. We studied the effects of PA gel stiffness on the migration, proliferation, and activation of CFs without and with CAN treatment, and characterized the reactive oxygen species (ROS) and glutathione (GSH) levels of CFs using fluorometry and scanning electrochemical microscopy (SECM). We found that CAN has the best amelioration efficacy in the cardiac function and NOX2 levels in rats with medium-stiffness myocardial tissue, and the most obvious anti-fibrosis and antioxidant efficacy in CFs on the medium-stiffness PA gels. Our work proves the effect of ECM stiffness on CAN efficacy in myocardial anti-fibrosis and antioxidants for the first time, and the results demonstrate that the effect of ECM stiffness on drug efficacy should also be considered in the treatment of cardiovascular diseases. [ABSTRACT FROM AUTHOR]