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The electrochemical analysis is one of the most popular implementations of a dopamine-sensing brain implant. Its performance depends significantly on the interaction between the dopamine molecule and the working electrode. Carbon nanofiber is an allotrope of carbon nanotube and is effective in increasing the contact surface with dopamine molecules. Considering its simple fabrication protocols using photolithography, physical vapor deposition, and electrochemical deposition, this material is suitable for in-vivo implementation. COMSOL simulation confirms that carbon nanofiber implementation increases the redox current while maintaining its linearity to the user-controlled dopamine concentration.

With the resurgence of electrosynthesis in organic chemistry, there is a significant increase in the number of routes available for late-stage functionalization (LSF) of drugs. Electrosynthetic methods, which obviate the need for hazardous chemical oxidants or reductants, offer unprecedented control of reactions through the continuous variation of the applied potential and the possibility of combination with photochemical processes. This capability is a substantial advantage for performing electrochemical or photoelectrochemical LSF. Ultimately, these protocols are poised to become a vital component of the medicinal chemist's toolkit. In this review, we discuss electrochemical protocols that have been demonstrated to be applicable for the LSF of pharmaceutical drugs, their derivatives, and natural substrates. We present and analyze representative examples to illustrate the potential of electrochemistry or photoelectrochemistry for the LSF of valuable molecular scaffolds.

Abstract In situ electrochemistry on micron and submicron-sized individual particles and thin layers is a valuable, emerging tool for process understanding and optimization in a variety of scientific and technological fields such as material science, process technology, analytical chemistry, and environmental sciences. Electrochemical characterization and manipulation coupled with soft X-ray spectromicroscopy helps identify, quantify, and optimize processes in complex systems such as those with high heterogeneity in the spatial and/or temporal domain. Here we present a novel platform optimized for in situ electrochemistry with variable liquid electrolyte flow in soft X-ray scanning transmission X-ray microscopes (STXM). With four channels for fluid control and a modular design, it is suited for a wealth of experimental conditions. We demonstrate its capabilities by proving the reversible oxidation and reduction of individual microbial biofilm structures formed by microaerophilic Fe(II)-oxidizing bacteria, also known as twisted stalks. We show spectromicroscopically the heterogeneity of the redox activity on the submicron scale. Examples are also provided of electrochemical modification of liquid electrolyte species (Fe(II) and Fe(III) cyanides), and in situ studies of electrodeposited copper nanoparticles as CO2 reduction electrocatalysts under reaction conditions.

Abstract In this research, we describe the first aptasensor for the detection of the Rift Valley Fever virus (RVFV). The process involved the selection of aptamers through the systematic evolution of ligands by the exponential enrichment (SELEX) technique. After 12 rounds of selection, 6 aptamers were selected and the corresponding binding affinities were assessed using fluorescence binding assays, revealing dissociation constants ranging from 15.45 to 40.98 nM. Notably, among the aptamers, RV2 and RV3 exhibited the highest binding affinities toward RVFV, with dissociation constants of 15.45 and 18.62 nM, respectively. Thiol-modified aptamers were subsequently immobilized onto screen-printed gold electrodes, facilitating the label-free detection of RVFV through square wave voltammetry. The voltammetric aptasensor demonstrated an excellent sensitivity, with a detection limit of 0.015 ng/mL. In addition, cross-reactivity assessments were conducted, where negligible response was obtained when the aptasensor was exposed to non-specific proteins.

In this work, AFM1 was chosen as the target, and the aptamer was split to solve the low sensitivity due to unstable structure of the aptamer. The recognition ability and specificity of the split aptamer were evaluated using electrochemical methods, and the binding mechanism was explored through the circular dichroism. The results showed that the split aptamer employing a 1:1 split mode exhibited the best performance in the recognition and specificity for AFM1. The circular dichroism spectrum remained unchanged. The positive peak intensity of the circular dichroism spectrum increased significantly and the negative peak moved and the intensity increased, which demonstrated that the conformation of the aptamer changed. The sensitivity was enhanced by employing split aptamers. Superior recognition elements for the construction of sensors was obtained by the fragmentation of intact aptamers. The investigation provides a new idea to enhance the sensitivity of the detection mehtods based on the apatamer.

Traditional physical methods for measuring solubility were often affected by viscosity, density, and surface tension. In this study, we selected appropriate electrolytes to determine the solubility of impurities in the lead-bismuth circuit at reactor operating temperatures using electrochemical methods. Taking the measurement of the solubility of impurity Ce in liquid Bi as an example, we demonstrated that electrochemical methods can accurately determine its solubility in the LiCl-KCl molten salt. Furthermore, the successful measurement of other impurities such as La, Ce, U, and Mn in lead-bismuth eutectic (LBE) using the designed system has confirmed the universality of this method.

The objective of the present investigation was to evaluate the parameters that affect the efficiency of electrocoagulation in a batch system to remove the azo-benzoic dye Red 40 present in synthetic wastewater by determining the effect of the operational parameters of voltage and treatment time. A 12×6 cm iron electrode holder was constructed with PVC pipes and screws separated by 2 cm, and a 1 L beaker was used as the electrocoagulation cell. Synthetic wastewater samples of red 40 were characterized, where UV–VIS was used to measure absorbance before and after being treated in the electrocoagulation cell. The effects of voltages (10, 15, and 20 V) and treatment times up to 60 min were evaluated. As a result, a higher removal of 93.85 % was obtained at 60 min when a voltage of 10 V was used with a lower change in temperature and energy consumption of only 14.08 kJ. The increase in conductivity and pH by values greater than 1600 µs/cm and 11, respectively, indicate the presence of diluted iron at the end of treatment; therefore, if complemented with other treatment methods such as filtration to remove excess iron produced, can be used in treatment plants and reduce their environmental impact, for this research the FTIR analysis showed that the sludge has a dye composition with hydroxides of metals along with a slight trace of dye degradation.

gem-Difluorination of carbon–carbon triple bonds was conducted using Brønsted acids, such as Tf2NH and TfOH, combined with Bu4NBF4 as the fluorine source. The electrochemical oxidation of a Bu4NBF4/CH2Cl2 solution containing alkyne substrates could also give the corresponding gem-difluorinated compounds (in-cell method). The ex-cell electrolysis method was also applicable for gem-difluorination of alkynes.

Iminoiodinanes comprise a class of hypervalent iodine reagents that is often encountered in nitrogen-group transfer (NGT) catalysis. In general, transition metal catalysts are required to effect efficient NGT to unactivated olefins because iminoiodinanes are insufficiently electrophilic to engage in direct aziridination chemistry. Here, we demonstrate that 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) activates N-arylsulfonamide-derived iminoiodinanes for the metal-free aziridination of unactivated olefins. 1H NMR and cyclic voltammetry (CV) studies indicate that hydrogen-bonding between HFIP and the iminoiodinane generates an oxidant capable of direct NGT to unactivated olefins. Stereochemical scrambling during aziridination of 1,2-disubstituted olefins is observed and interpreted as evidence that aziridination proceeds via a carbocation intermediate that subsequently cyclizes. These results demonstrate a simple method for activating iminoiodinane reagents, provide analysis of the extent of activation achieved by H-bonding, and indicate the potential for chemical non-innocence of fluorinated alcohol solvents in NGT catalysis.

Abstract The pretreatment and saccharification of dewaxed bagasse (DWB) has been investigated under various reaction conditions ranging 2000 to 3200 psi, at 70 ± 1 °C in supercritical carbon dioxide (SCC). This has been in attempt to transform the DWB into fermentable sugar and bioethanol in high yields. The effect of SCC mediated pretreatment and enzymatic hydrolysis on structural and morphological alterations in DWB has been ascertained through diverse analytical methods. The sugar has been released through cellulase (40 FPU/mL) mediated enzymatic hydrolysis of pretreated DWB in sodium acetate buffer (pH 4.7) within 1 h at SCC 2800 psi, 70 ± 1 °C. The released sugar was subsequently fermented in the presence of yeast (Saccharomyces crevices, 135 CFU) at 28 ± 1 °C over 72 h to afford the bioethanol. The SCC mediated process conducted in acetic acid:water media (1:1) at 2800 psi, 70 ± 1 °C over 6 h has afforded the pretreated DWB with maximum yield towards the production of fermentable sugar and bioethanol. The production of fermentable sugar and bioethanol has been electrochemically estimated through cyclic voltammetry (CV) and square wave voltammetry (SWV) over glassy carbon electrode in KOH (0.1 M). The electrochemical methods were found selective and in close agreement for estimation of the yields (%) of fermentable sugars and bioethanol. The yield (%) of fermentable sugar estimated from CV and SWV were 80.10 ± 5.34 and 79.00 ± 5.09 respectively. Whereas the yield (%) of bioethanol estimated from CV and SWV were 81.30 ± 2.78% and 78.6 ± 1.25% respectively. Present investigation delivers a SCC mediated green and sustainable method of pretreatment of DWB to afford the enhanced saccharification, to produce bioethanol in high yields.

Abstract We present a new simple approach for electrochemical synthesis of semi-condensed ambipolar perinone polymers with phthaloperine (p1) or phenanthroline (p2) skeleton from available and cheap perimidine precursors. Polymerization of perimidine derivatives varies in efficiency depending on the monomer, but overall is highly efficient, especially when electropolymerization is used. Electrooxidation is well controllable and provides a certain characteristic share of new bonds in the structure of perimidine polymers: semi-ladder bis-perimidine unit, ladder bis-perimidine unit, and protonated bis-perimidine unit. Polymer p2 obtained with higher efficiency was put through broader analysis (UV–Vis, IR, ESR and quantum-chemical calculations). As indicated, donor–acceptor structure and specific intermolecular interactions of p2 assure its electrical conductivity and complex redox activity. Although protonated bonds break π-conjugation in the structure of the macromolecule, there is also a diradical state that favors intermolecular interactions and intermolecular π-conjugation channels within bis-perimidine segments. It has been proven that there is a diradical state which appears as an intermediate state between the oxidized and reduced states of the protonated polymer unit. This work positions perimidine polymers as a versatile ambipolar multiredox p- and n-type conductor, indicating a potential for expanding perinone-based perylene-diperimidine polymers for innovative electronics and (bio)sensors.

Developing new materials for Li-ion and Na-ion batteries is a high priority in materials science. Such development always includes performance tests and scientific research. Synchrotron radiation techniques provide unique abilities to study batteries. Electrochemical cell design should be optimized for synchrotron studies without losing electrochemical performance. Such design should also be compatible with operando measurement, which is the most appropriate approach to study batteries and provides the most reliable results. The more experimental setups a cell can be adjusted for, the easier and faster the experiments are to carry out and the more reliable the results will be. This requires optimization of window materials and sizes, cell topology, pressure distribution on electrodes etc. to reach a higher efficiency of measurement without losing stability and reproducibility in electrochemical cycling. Here, we present a cell design optimized for nuclear resonance techniques, tested using nuclear forward scattering, synchrotron Mössbauer source and nuclear inelastic scattering.

The electrochemical interaction between galena and monoclinic pyrrhotite was investigated to examine its impact on the physical and chemical properties of the mineral micro-surface. This investigation employed techniques such as electrochemistry, metal ion stripping, X-ray photoelectron spectroscopy, and quantum chemistry. The electrochemical test results demonstrate that the galena surface in the electro-couple system exhibits a lower electrostatic potential and higher electrochemical activity compared to the monoclinic pyrrhotite surface, rendering it more susceptible to oxidation dissolution. Monoclinic pyrrhotite significantly amplifies the corrosion rate of the galena surface. Mulliken charge population calculations indicate that electrons are consistently transferred from galena to monoclinic pyrrhotite, with the number of electron transfers on the mineral surface increasing as the interaction distance decreases. The analysis of state density revealed a shift in the surface state density of galena towards lower energy levels, resulting in decreased reactivity and increased difficulty for the reagent to adsorb onto the mineral surface. Conversely, monoclinic pyrrhotite exhibited an opposite trend. The X-ray photoelectron spectroscopy (XPS) test results indicate that galvanic interaction leads to the formation of hydrophilic substances, PbSxOy and Pb(OH)2, on the surface of galena. Additionally, the surface of monoclinic pyrrhotite not only adsorbs Pb2+ but also undergoes S0 formation, thereby augmenting its hydrophobic nature.

In the process of heat treatment of 8620 low alloy steel, the heating rate is a critical parameter that must be carefully controlled to achieve the desired combination of microstructural features, mechanical properties, and corrosion resistance while simultaneously ensuring process efficiency and cost-effectiveness. This study investigates, for the first time, the microstructural evolution and electrochemical properties of 8620 steel under identical quenching and tempering heat treatment routes with slow-rate (SR) and fast-rate (FR) heating rates. Microstructural analysis revealed martensitic phases for SR, while FR exhibited a dual-phase microstructure containing ferrite. Upon tempering, for both samples, the martensite transformed into tempered martensite, with tempered (Temp) FR exhibiting around 50% smaller ferrite grains. Mechanical testing indicated that SR had 17% higher hardness than FR, although hardness decreased after tempering by 22% (SR) and 17% (FR). All electrochemical tests indicated that the as-quenched SR exhibited significantly superior corrosion resistance than FR. For instance, the polarization resistance of SR was 440 Ω higher than that of the FR samples. Tempering resulted in a considerable decrease in corrosion resistance for Temp SR, whereas Temp FR improved. Electrochemical characterization revealed Temp FR displayed close-to-ideal capacitive behavior and low double-layer capacitance, indicating enhanced overall corrosion resistance.

Cu2(ZnSn)(S)4 (copper, zinc, tin, and sulfide (CZTS)) provides possible advantages over CuInGaSe2 for thin-film photovoltaic devices because it has a higher band gap. Preparing CZTS by electrodeposition because of its high productivity and lower processing costs, electroplating is appealing. Recently published studies reported that the electrodeposition process of CZTS still faces significant obstacles, such as the sulfur atomic ratio (about half of the whole alloy), deposits’ adhesion, film quality, and optical properties. This work introduces an improved bath that facilitates the direct electroplating of CZTS from one processing step. The precursors used were significantly more diluted than the typical baths mentioned in the last few years. An extensive analysis of the electrochemical behavior at various rotation speeds is presented at room temperature (~22 °C). The deposited alloy’s composition and adherence to the molybdenum back contact are examined with agitation. The annealing process was carried out in an environment containing sulfur, and the metal was not added at this stage. The ultimate sulfur composition was adjusted to 50.2%, about the desired atomic ratio. The compound’s final composition was investigated using the Energy-Dispersive X-ray Spectroscopy technique. Finally, X-ray diffraction analysis was applied to analyze CZTS crystallography and to measure thickness.

Electrochemical or photochemical single-electron oxidation of bench-stable substrates can generate radical cations that offer unique reactivities as intermediates in various bond-formation processes. Such intermediates can potentially take part in both radical and ionic bond formation; however, the mechanisms involved are complicated and not fully understood. Herein, we report electrochemical radical cation aza-Wacker cyclizations under acidic conditions, which are expected to proceed via radical cations generated by single-electron oxidation of alkenes.

Extracting uranium from seawater is an effective strategy for sustainable nuclear fuel supplementation. Uranium in seawater mainly exists in the form of hexavalent uranyl(U(Ⅵ)), although the total amount is large, the mass fraction of U(Ⅵ) is only 3.3×10−9, and many metal ions coexist with uranium. Extracting uranium from seawater is extremely challenging. Electrochemical seawater uranium extraction has become an emerging method for seawater uranium extraction due to its advantages over physical and chemical adsorption processes, such as fast reaction rate, strong anti-interference ability, and simple desorption. However, due to the lack of research on the structure-activity relationship between catalysts and uranium extraction performance, the rational design of highly active electrocatalysts remains a challenge. In this work, we proposed an interface bonding strategy by using a simple hydrothermal method to bond the {2 2 2} fact of octahedral Fe3O4 to the {0 0 2} fact of MoS2. This significantly improves the electron transfer rate at the interface and the cycling stability of Fe3O4, verifying the feasibility of interface bonding for the electrochemical extraction of uranium from seawater. After 7 hours of electrochemical extraction in a simulated solution, the extraction efficiency of uranium can reach 96%. Meanwhile, the experimental results of coexisting ion extraction of uranium indicated that MoS2/Fe3O4 has good selectivity for uranium and anti-interference ability against coexisting ions. Electrochemical extraction is also performed in 10 L natural seawater with a yield of 27.2 μg. The extraction amount of uranium is 5.44 mg/g. A series of characterizations such as XPS and HRTEM, show that Fe3O4 is dispersed on the surface of MoS2 and effectively bound through interfacial interactions. This dispersion effectively solves the aggregation problem of Fe3O4, and the stability of MoS2 structure ensures the cycling stability of Fe3O4. By combining the MoS2 and Fe3O4 at the interface, an efficient electron transfer channel can be constructed, accelerating electron transfer and achieving the goal of simultaneously improving the selectivity, stability, and electron transfer rate of the catalyst. Therefore, the interfacial regulation strategy proposed in this work utilizes the synergistic effects of different components in the composite material to achieve stability and the cyclicity of the catalyst in seawater uranium extraction. At the same time, the interface control strategy will also provide a feasible solution for achieving efficient reduction and extraction of uranyl in a series of complex environments such as seawater. And the electron transfer path and the species change of uranium during catalytic reduction need to be further explored in the mechanism analysis in this work.

In order to solve the problems of frequent electrode cleaning and low efficiency in electrochemical descaling, a new electrochemical water softening reactor with horizontal electrodes was developed. In the new electrochemical water softening reactor, the inflow flowed horizontally through the cathodic chamber and then the anodic chamber. The movement of water and bubbles promoted OH- diffusion and strengthened the homogeneous nucleation of CaCO3. By optimizing current density, flow rate and initial hardness, the homogeneous nucleation was strengthened. At the flow rate of 2.7 L/h, the current density of 80 A/m2 and the influent hardness of 400 mg/L, the softening efficiency was achieved as 155 g/(h·m2), hardness removal was 150 mg/L, current efficiency was 50% and energy consumption was 15 kW·h/g. With these performance, cathodic cleaning frequency was reduced effectively.

Abstract HRB500E rebar is a low-alloy high-strength steel with excellent mechanical properties and good plasticity but suffers from deficient corrosion resistance. This can be solved by adding trace elements, including rare earth elements. Herein, the corrosion-resistant behavior of rebar was evaluated by weightlessness testing and electrochemical measurements, and the effects of Ce on the structural evolution of the corrosion product layer were investigated by scanning electron microscopy (SEM), Electron Probe X-ray Micro-Analyzer (EPMA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that adding Ce to the rebar improved the densification of the reinforcing surface corrosion products, as well as reduced the corrosion rate of the experimental rebar. Compared to C0 sample without Ce, the rebar sample containing 0.044 wt.% Ce displayed increased Ecorr by 0.051 V, decreased Icorr by 15.573 mA cm−2, enhanced Rc of the corrosion product layer by 112.71 Ω cm2, incremented α-FeOOH content in the corrosion product layer, and boosted ratio of α/γ* in the corrosion product layer by 10.11%. Furthermore, the oxide (CeO2) formed by Ce in the corrosion layer of the rebar bar surface existed in the rust layer, resulting in a stable corrosion product layer with improved blocking ability of the corrosive medium. Overall, the addition of Ce at certain ratios looks promising to produce HRB500E rebar with excellent corrosion resistance and extended service life under harsh conditions.

For investigating the microbial corrosion behavior of water supply pipelines in thermal power plants using regenerated water as the water source, a circular biofilm hanging plate reactor was used to dynamically simulate the operation status of the regenerated water pipeline. The influence process and mechanism of iron bacteria(IOB), sulfate reducing bacteria(SRB) and their mixture on the corrosion of Q235 steel were studied by measuring the pH value and conductivity of the solution, weight loss of the specimen, electrochemical parameters(such as redox potential, polarization curve, AC impedance), bacterial count, and combining SEM, EDS, XRD and other methods. Results showed that the number of two types of bacteria increased over time, and the pH value of the regenerated water first decreased and then increased, while the conductivity steadily increased. Furthermore, the number of bacteria in the environment was positively correlated with the corrosion rate of pipes at this time, and SRB were the main bacterial species that affected microbial corrosion. Through EDS and XRD analysis, it was found that the main components of corrosion products varied in different environments: the corrosion products during IOB process were mainly FeOOH, with a small amount of Fe2O3 and Fe3O4; the main corrosion products during SRB process were iron oxide and iron sulfide; When SRB+IOB coexisted, the main corrosion products were Fe2O3, Fe3O4 and FeS. Besides, the microbial film and corrosion products generated on the surface of the pipeline in the early stage would inhibit the corrosion of Q235. In the later stage, the deactivation of the microbial film and the detachment of the covered corrosion products would accelerate the corrosion.

For exploring the effect of thiourea on the corrosion resistance of waterborne acrylic resin organic silane composite passivation film on Zn-Al-Mg coating, an aqueous acrylic resin-organosilane was used as the main film-forming material, and different contents of thiourea were added to formulate a chromium-free passivate solution for the composite passivation of Zn-Al-Mg coatings. The particle size of thiourea was measured by Nano ZS90 nanoparticle size analyzer, and the structure of thiourea was tested by Nicolet 6700 Fourier transform infrared spectrometer(FTIR). In addition, the corrosion resistance of the composite passivation film was analyzed through full immersion test, electrochemical test and neutral salt spray test, and the effect of thiourea content on the corrosion rate of the composite passivation film was explored. Results showed that thiourea possessed an inhibitory effect on the corrosion resistance of Zn-Al-Mg coatings, but too much thiourea could lead to a decrease in the corrosion inhibition of the passivation film. Compared with three different addition amounts of thiourea, the corrosion resistance of the Zn-Al-Mg coating was optimal when the mass fraction of thiourea in the passivation solution was 0.5%. Furthermore, thiourea and waterborne acrylic resin organic silane underwent cross-linking, and after corrosion, they formed a complex with metals, forming a dense network structure, which improved the density of the film layer and reduced the corrosion rate of the film layer.

Aiming at the high cost and poor effect of catalytic materials for cathodic oxygen reduction reaction(ORR) in electrochemical deoxygenation, NiCoFe ternary alloy was efficiently prepared by electrodeposition under different current densities, and the morphology and structure of the alloy material were characterized and analyzed, which showed that NiCoFe alloy had a fluffy cauliflower-like surface morphology and alloy crystalline structure. The ORR performance of the NiCoFe alloy was tested in a three-electrode system at different current densities. When the electrodeposition current density was 1.0 A/cm2, the alloy was obtained with a half-wave potential of 0.782 V, an onset potential of 0.936 V, and a limiting current density of 2.9 mA/cm2. The rotating ring disk electrode(RRDE) test showed that the number of transferred electrons of the alloy was 3.52, which was close to that of the four-electron transfer of commercial Pt/C catalysts. An electrochemical deoxidation test equipment was designed to investigate the removal effect of NiCoFe alloy as a cathode electrode on dissolved oxygen in simulated industrial water. The results showed that the deoxidation rate of NiCoFe cathode was over 99%, making it an excellent ORR electrocatalyst material.

Abstract Gemini-type imidazoline quaternary ammonium salt is a new type of environmentally friendly corrosion inhibitor has been widely used in engineering materials. However, most of them are hazardous/toxic compounds derived from petroleum-based products, which did harm to environment. In this work, an environmentally friendly Gemini-shaped imidazoline quaternary ammonium salt corrosion inhibitor (G211) was synthesized using cheap fatty acid recycled from dimer acid industry as feedstock. The corrosion inhibition effects of G211 on Q235 steel in 1 M HCl solution were investigated through weight loss experiments, potential polarization curves, and alternating current impedance spectroscopy experiments. The results show that the inhibition rate of G211 as a mixed-type inhibitor is up to 94.4% and the concentration drop as low as 500 ppm at 25 ℃. The adsorption of G211 on Q235 surface follows Langmuir adsorption isothermal curve. The chemical composition of the Q235 steel surface was analyzed through scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Furthermore, the possible corrosion inhibition mechanism of G211 on the surface of Q235 steel is proposed. This article not only presents an outstanding solution for safeguarding Q235 steel against corrosion but also introduces a feasible method for high-value utilization of monomer acid (MA).

Aiming at the corrosion problem of steel bars in concrete in subtropical marine environment, the full immersion corrosion experiments of reinforced concrete specimens with different strength grades and rust inhibitor contents were carried out by simulating the subtropical marine environment.The macroscopic indexes such as chloride ion content were tested by electrochemical non-destructive testing, and the experimental results were verified by microscopic detection methods.The corrosion degradation patterns of reinforced concrete was analyzed.The results show that the improvement of concrete strength grade and the increase of rust inhibitor content can significantly improve the corrosion resistance of reinforced concrete.Among them, the corrosion resistance of C30 concrete is the worst.At 120 d, the corrosion current density is 0.118 μA/cm2, the polarization resistance is 220 kΩ cm2, the concrete resistance is 87.3 kΩ cm2, and the transfer resistance of the steel-concrete interface area is 77.3 kΩ cm2, reaching the passivation state.When the concrete strength grade is increased to C50, the corrosion current density is reduced by 58.47%, the polarization resistance is increased by 3.82 times, and the concrete resistance is increased by 44.56%;when the amount of rust inhibitors is 6 kg/m3, the corrosion current density is reduced by 47.45%, the polarization resistance is increased by 2.81 times, and the transfer resistance at the reinforcement-concrete interface is increased by 72.43%.

Abstract Herein, the study reports the first electrochemical nickel‐catalyzed enantioselective hydro‐arylation/alkenylation of enones in an undivided cell with low‐cost electrodes in the absence of external reductants and supporting electrolytes. Aryl bromides/iodides/triflates or alkenyl bromides are employed as electrophiles for the efficient preparation of more than 56 valuable β‐arylated/alkenylated ketones in a simple manner (up to 97% yield, 97% ee). With the advantages of electrochemistry, excellent functional group tolerance and late‐stage modification of complex natural products and pharmaceuticals made the established protocol greener and more economic. Mechanism investigation suggests that a NiI/NiIII cycle may be involved in this electro‐reductive reaction rather than metal reductant driven Ni0/NiII cycle. Overall, the efficient electrochemical activation and turnover of the nickel catalyst avoid the drawbacks posed by the employment of stoichiometric amount of sensitive metal powder reductants.

Abstract Electrosynthetic reactions are performed in either custom‐made reactors that are developed and machined in‐house or commercially available systems that offer good reproducibility but come at a high cost. To bridge this divide between customizability and reproducibility, we have developed the Open‐ESyn, which is a suite of 3D‐printed components compatible with the popular ElectraSyn. This collection of parts increases the electrosynthesis that can be performed with the ElectraSyn, expanding, for example, the scale, temperature and the type of electrodes that can be used. The standardized reactor environment can be inexpensively recreated, thereby maintaining the reproducibility of the ElectraSyn ecosystem.

Summary: Current solid- and liquid-state electrode materials with extreme physical states show inherent limitation in achieving the ultra-stable batteries. Herein, we present a colloidal electrode design with an intermediate physical state to integrate the advantages of both solid- and liquid-state materials. The colloidal electrode was designed based on the inherent water competition effect of (SO4)2− from the aqueous electrolyte and inherently water-soluble polyethylene glycol (PEG)/ZnI2 from the cathode. The constructed aqueous Zn||PEG/ZnI2 colloid battery demonstrated ultra-stable cycling performance with Coulombic efficiencies approaching 100% and a capacity retention of 86.7% over 10,700 cycles, without requiring anodic modification. In addition, the battery also exhibits compatibility with multiple operating conditions including fluctuating charging, limited self-discharging rate, different charging statuses, and fast charging. Moreover, the battery also shows practical potential by integrating with a photovoltaic solar panel charging. This design provides a broad platform for building the next-generation aqueous batteries with ultra-long lifetime.

Nitrogen-doped quenched-produced diamond (N-doped Q-dia) thin films were deposited onto a titanium substrate by coaxial arc plasma deposition (CAPD). The N-doped Q-dia thin film was successfully synthesized at room temperature without peeling. Its performance as an electrode material in aqueous solutions was investigated. The overpotential for the hydrogen evolution reaction was 0.35 V higher than the conventional boron-doped diamond (BDD) electrode. The kinetics of reversible electron transfer for redox species were comparable to the BDD electrode. We have demonstrated the N-doped Q-dia thin films have promising potential as a competitive and alternative electrode material to BDD films for electrochemical applications.

Abstract To design a high‐efficiency crystalline silicon (c‐Si) photocathode, the photovoltage and photocurrent generated by the device must be maximized because these factors directly affect the hydrogen evolution reaction (HER). In this study, a c‐Si p–n junction is used to enhance the photovoltage of the c‐Si photocathode, and a tapered microwire array structure is introduced to increase the photocurrent. When tapered microwire arrays are employed on the front surface of the c‐Si photocathode, a current density of ≈41.7 mA cm−2 is achieved at 0 VRHE (reversible hydrogen electrode); this current density is the highest among all reported photocathodes including c‐Si, approaching the theoretical maximum value for c‐Si. Furthermore, a Ni foil/Pt catalyst is introduced on the opposite side of the incident light, simultaneously serving as an electrocatalyst to reduce side reactions in the HER and encapsulation layer to prevent c‐Si from contacting the electrolyte. Thus, a stable device is developed using c‐Si photoelectrochemical cells that have an efficiency exceeding 97% for >1000 h.

The outdoor operation of electrochemical solar fuels devices must contend with challenges presented by the cycles of solar irradiance, temperature, and other meteorological factors. Herein, we discuss challenges associated with these fluctuations presented over three timescales, including the effects of diurnal cycling over the course of many days, a single diurnal cycle over the course of hours, and meteorological phenomena that cause fluctuations on the order of seconds to minutes. We also highlight both reaction-independent and reaction-specific effects of variable conditions for the hydrogen evolution reaction and CO2 reduction reaction. We identify key areas of research for advancing the outdoor operation of solar fuels technology and highlight the need for metrics and benchmarks to enable the comparison of diurnal studies across systems and geographical locations.

Abstract Screen‐printed electrochemical sensing platforms are ubiquitous within the field of electrochemistry where they provide benefits of being disposable, cost‐effective, reproducible, easily customisable, portable and allow one to transfer the laboratory approach into the field. In this review, we introduce the concept of screen‐printed electrodes, we summarise positive and negative aspects before moving into the current highlights of using traditional screen‐printed carbon electrodes within the field of electroanalysis. We then look to cover metallic and bulk modified varieties, geometric changes (micro, microband and associated arrays), electrode activation and finally the physical length of screen‐printed electrodes, providing insights for future research.

Abstract Electrochemical sensors based on self‐assembled monolayer (SAM) were synthesized using metal‐organic frameworks (MOFs), quantum dots (QDs) and their composite (QDs@MOFs) to modify gold electrode (AuE) that was used as electrochemical sensors for bisphenol A detection. The molecular layer was assembled on the surface of the gold electrode by adsorption and provide a highly flexible method to tailor the interfaces between analyte and the electrode. Single crystal X‐ray of the MOF revealed a six‐coordinate copper(II) ion that bidentately coordinate two molecules of p‐anisic acid and two molecules of 1H‐benzimidazole to form a distorted octahedral geometry around the copper(II) ion. Electrochemical studies revealed that under optimal conditions, the modified gold electrode sensors show excellent sensing of bisphenol A, however, QDs@MOFs modified electrode is the best sensor with the highest oxidation peak current of 8.43E‐05 μA and the lowest charge transfer resistance of 19.4 Ω within a wide concentration range of 0.1–1 μM and a limit of detection (LOD) of 0.252 μM. This could be attributed to the electrocatalytic activity of the composite (QDs@MOFs) modified sensor, and the synergistic effect of the MOFs and QDs in the composite. The LOD is comparable to other electrochemical methods of sensing BPA which indicates that QDs@MOFs modified gold electrode could be develop as sensor for BPA.

Inorganic scale formation is a common issue in multi-stage flash (MSF) desalination plants, significantly impacting operational efficiency. To address this, acid cleaning is frequently employed, but it can lead to severe corrosion of alloy components if not properly controlled with corrosion inhibitors. This study investigates the effectiveness of toluene-2,4-diisocyanate-4-(1H-imidazole-ly) aniline (TDIA) as a corrosion inhibitor for 304L stainless steel in a simulated acid cleaning solution (1M HCl and 3.5 % NaCl). A range of tests, including electrochemical analysis, weight loss measurements, and surface characterization techniques such as AFM, EDS, and SEM, were used to assess the inhibitor's performance at temperatures of 25, 45, 65, and 90 °C. At a concentration of 50 ppm, TDIA achieved inhibition efficiencies of around 90% at 25 °C and above 80% at 90 °C, demonstrating effective protection across all temperatures studied. The adsorption behavior of TDIA followed the Langmuir adsorption model, and it acted as a mixed-type inhibitor by forming a protective layer on the metal surface, which prevents corrosive agents from accessing the steel. The dual-environment testing method, simulating conditions in desalination plants, offers valuable insights into the inhibitor's practical performance, enhancing the applicability of these findings to real-world industrial scenarios.

Aflatoxin B1 (AFB1) is a potent toxin in food, necessitating rapid, instant, and sensitive detection. We have engineered an electrochemical sensor to monitor AFB1 using a system composed of Fe3O4-NH4/AuNPs/apt-S1. The aptamer specifically recognizes AFB1, while ‘S1’ is functionalized with methylene blue to enhance the current. The RecJf exonuclease promotes the formation of the electrochemical strategy. The Fe3O4 component, with its magnet properties, enables a rapid separation of solids and liquids without the need for instrumentation. The sensor exhibits a linear range for AFB1 ranging from 1 ng to 10 μg. The regression equation is I(nA) = 446.8 × logc+2085 (where I and c represent the peak current and AFB1 concentration, respectively). The correlation coefficient is 0.9508, and the detection limit is 3.447 nM. The relative standard deviation of AFB1 in peanut oil ranges from 4.80% to 6.80%. These results demonstrate that the sensor has high sensitivity, stability, repeatability, and specificity for AFB1 detection.

Abstract The electrochemical applications of gold span the entire pH spectrum. Recently, gold dissolution in acidic and alkaline media has been studied, but less attention has been given to electrolytes at intermediate pH values. To address this gap, this work uses on‐line electrochemical dissolution inductively coupled plasma mass spectrometry (ICP‐MS) to examine gold dissolution across a pH range of 1 to 12.7 using phosphate buffer solutions. All experimental parameters, except pH, are kept constant, enabling a clear investigation of pH effects on anodic (gold oxidation) and cathodic (gold oxide reduction) dissolution processes. Results show that dissolution amounts are lowest at neutral pH values between 3 and 7, varying with the applied potential and exposure time. Anodic and cathodic dissolution dominate in acidic and alkaline electrolytes, respectively. Depending on the highest applied potentials and time exposure, the main dissolution mechanism shifts at pH=5, 7, and 9. The pH dependence of Au dissolution is proposed to be linked to the nature of gold oxides formed, the kinetics of oxide formation/reduction, gold ion redeposition, and the influence of the oxygen evolution reaction (OER) on dissolution. These results provide fundamental insights into gold dissolution under neutral pH conditions.

Abstract Coupling surface plasmon resonance (SPR) sensing with electrochemistry (EC) is a promising analytical strategy to obtain information about interfacial phenomena in heterogeneous reactions. Typical EC‐SPR sensors utilize a metal film both as the plasmonic material and as the working electrode. In this configuration, the eigenmodulation of the plasmonic properties of the metal film under applied potential results in a background signal, which hampers the unambiguous interpretation of the sensor response due to redox reactions. Here, a new strategy is presented to overcome this disadvantage by using a van der Waals heterostructure (vdW‐HS) as the working electrode. The vdW‐HS comprises of a graphene / hexagonal boron nitride (hBN) stack on a gold film of a standard SPR sensor. It is shown here that the background signal is completely suppressed enabling the unambiguous analysis of SPR sensor response due to electrochemical reactions. It is further observed that the potential dependent plasmonic signals are not just a reproduction of the electrochemical current and subtle differences can be traced back to the diffusive nature of the redox active species. Finally, it is demonstrated that EC‐SPR can be used as a complementary method to distinguish if the electrochemical response is mainly surface‐bound or due to diffusion.

Electrochemical Impedance Spectroscopy (EIS) is a widely used, nondestructive electrochemical technique for analyzing many different systems. Currently, the most popular analysis method for EIS data is via Equivalent Circuit Models (ECMs). Many programs exist for constructing ECMs and fitting them to data, but these programs are often closed-source. In this work, we present an open-source program for equivalent circuit modeling called DECiM, which relies heavily on human input but is easy to operate. With two examples, we show how DECiM can easily and effectively validate spectra and construct and fit ECMs to data. The simple structure and open-source nature of DECiM make implementing new features easy, rendering the program versatile for impedance data analysis.

Abstract Layered composite oxide materials with O3/P2 biphasic crystallographic structure typically demonstrate a combination of high capacities of the O3 phase and high operation voltages of the P2 phase. However, their practical applications are seriously obstructed by difficulties in thermodynamic phase regulation, complicated electrochemical phase transition, and unsatisfactory cycling life. Herein, we propose an efficient structural evolution strategy from biphase to monophase of Na0.766+xLixNi0.33−xMn0.5Fe0.1Ti0.07O2 through Li+ substitution. The role of Li+ substitution not only simplifies the unfavorable phase transition by altering the local coordination of transition metal (TM) cations but also stabilizes the cathode–electrolyte interphase to prevent the degradation of TM cations during battery cycling. As a result, the thermodynamically robust O3‐Na0.826Li0.06Ni0.27Mn0.5Fe0.1Ti0.07O2 cathode delivers a high capacity of 139.4 mAh g−1 at 0.1 C and shows prolonged cycling life at high rates, with capacity retention of 81.6% at 5 C over 500 cycles. This work establishes a solid relationship between the thermodynamic structure evolution and electrochemistry of layered cathode materials, contributing to the development of long‐life sodium‐ion batteries.

Abstract Hybrid ion capacitors (HICs) have aroused extreme interest due to their combined characteristics of energy and power densities. The performance of HICs lies hidden in the electrode materials used for the construction of battery and supercapacitor components. The hunt is always on to locate the best material in terms of cost‐effectiveness and overall optimized performance characteristics. Functionalized biomass‐derived porous carbons (FBPCs) possess exquisite features including easy synthesis, wide availability, high surface area, large pore volume, tunable pore size, surface functional groups, a wide range of morphologies, and high thermal and chemical stability. FBPCs have found immense use as cathode, anode and dual electrode materials for HICs in the recent literature. The current review is designed around two main concepts which include the synthesis and properties of FBPCs followed by their utilization in various types of HICs. Among monovalent HICs, lithium, sodium, and potassium, are given comprehensive attention, whereas zinc is the only multivalent HIC that is focused upon due to corresponding literature availability. Special attention is also provided to the critical factors that govern the performance of HICs. The review concludes by providing feasible directions for future research in various aspects of FBPCs and their utilization in HICs.

Abstract The cathode surface of sulfide‐based all‐solid‐state batteries (SBs) is commonly coated with amorphous‐LiNbO3 in order to stabilize charge–discharge reactions. However, high‐voltage charging diminishes the advantages, which is caused by problems with the amorphous‐LiNbO3 coating layer. This study has investigated the degradation of amorphous‐LiNbO3 coating layer directly during the high‐voltage charging of SBs. O2 generation via Li extraction from the amorphous‐LiNbO3 coating layer is observed using electrochemical gas analysis and electrochemical X‐ray photoelectron spectroscopy. This O2 leads to the formation of an oxidative solid electrolyte (SE) around the coating layer and degrades the battery performance. On the other hand, elemental substitution (i.e., amorphous‐LiNbxP1‐xO3) reduces O2 release, leading to stable high‐voltage charge–discharge reactions of SBs. The results have emphasized that the suppression of O2 generation is a key factor in improving the energy density of SBs.

Abstract In this study, ZnCo2O4/Ag3PO4 composite catalyst was prepared by the precipitation method, and their performance in the photocatalytic degradation of methyl orange (MO) was studied. The catalysts were characterized by scanning electron microscopy, high‐resolution transmission electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, selected area electron diffraction, X‐ray photoelectron spectroscopy, and UV‐Vis diffuse reflectance spectroscopy. The results indicate that the 0.1 ZnCo2O4/Ag3PO4 composite system has good photocatalytic activity in the degradation of methyl orange. Under simulated sunlight conditions, the degradation rate can reach 94% after 30 min. The maximum reaction rate constant of 0.1 ZnCo2O4/Ag3PO4 was 0.05301 min−1, which is 3 times and 52 times the rate constant of pure Ag3PO4 and pure ZnCo2O4, respectively. In catalyst recycling experiments, 0.1 ZnCo2O4/Ag3PO4 still degraded methyl orange at a rate of 84.4% after three cycles. Trapping experiments showed that holes and superoxide radicals mostly contributed to the photocatalytic degradation of methyl orange by the catalyst, while hydroxyl radicals played a partial role. The energy level structure of ZnCo2O4/Ag3PO4 is conducive to the effective separation of photogenerated electrons and holes, improving the lifespan of photogenerated charges. In the investigated catalyst series, 0.1 ZnCo2O4/Ag3PO4 demonstrated the best photocatalytic performance.

Green corrosion inhibitors are crucial in lowering the rate at which metals corrode as well as the negative environmental effects of hazardous substances. Considering this, Curcuma longa (CL) root extract was used as an effective and safe corrosion inhibitor in this study. The inhibitory efficacy was thoroughly investigated using the weight loss (WL), open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) techniques, respectively. The inhibitor was found to be effective at impeding the rate of deterioration of mild steel in 1 M HCl and 0.5 M H2SO4 environments. In a mixed-type mode, the CL reduced the anodic and cathodic reactions. However, in a 0.5 M H2SO4 environment, CL proved to be slightly more effective compared to a 1 M HCl environment. Inhibition efficiency values of 91.8 % (0.5 M H2SO4) and 89.6 % (1 M HCl) were obtained. The Langmuir adsorption isotherm (LAI) was used to validate the results. Some surface probe analysis such as scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FR-IR), and X-ray photoelectron spectroscopy (XPS), were used to complement the electrochemical results. Quantum chemical computations confirmed some active sites on the molecular structures of a few selected active constituents of the CL extract.

Summary: Fast and efficient galvanostatic conversion of 2,4-diarylfurans into dimeric furan-2(5H)-ones is now possible in one pot and good yields at room temperature in sustainable aqueous organic solvent. Recent applications of these highly desired structures demand our attention since they are a versatile alternative to acrylates in polymerization to achieve green materials. The reaction mechanism proposal, supported by density functional theory (DFT) theoretical calculations, involves furanoxy radicals, detected by electron paramagnetic resonance (EPR), as the last intermediate before a homocoupling step that affords butenolides. The process can be successfully extended to an array of electron-donating and electron-withdrawing substituents on the aromatic ring. The proposed pathways to explain the formation of the products are rationalized and discussed. A concomitant oxidation of water to hydroxyl radicals is not discarded, particularly with electron-withdrawing substituents at the aromatic ring. In addition, the biological activity as biocides of the obtained compounds was tested, and they showed promising activity against Staphylococcus aureus.

Abstract In scanning electrochemical microscopy (SECM), the addition of a redox active species plays an essential role. Those deliberately added mediators may alter results in SECM studies. In investigations of lithium‐ion battery (LIB) materials, especially of the positive electrode, the oxidation potentials of commonly used mediator substances such as ferrocene are located within the operation potential of the electrode. Thus, they possibly interfere with the regular charge/discharge processes. In situ studies are therefore in need of approaches reducing or eliminating the use of mediators. Within this publication, a novel mediator dosing (MD) concept is introduced. A capillary was closely positioned at the tip of the scanning probe. By gravity flow, stable flow rates of mediator solution of up to 32.4±0.6 μL h−1 were achieved. These low amounts were found to be sufficient to form a ferrocene zone at the probe tip enabling feedback mode SECM measurements with comparable quality to measurements directly in ferrocene solution. Proof of concept experiments were conducted by investigation of a thin‐film electrode with a micro‐structured surface. Furthermore, the MD concept was applied in imaging experiments of a commercially available LIB graphite electrode.

Abstract The aim of this investigation was to explore the possibility to perform an asymmetric reduction, utilising a CBS‐type catalyst, of prochiral aryl methyl ketones under electrochemical conditions to generate the needed BH3 upon oxidation of NaBH4 with in situ generated I2 in the anode compartment. Therefore, various electrochemical parameters were optimised to conduct the desired formation of the chiral secondary alcohols in high to quantitative yields with a high stereochemical induction, although the catalyst loading had to be chosen relatively high to concur with the racemic reduction of the ketones by the electrogenerated BH3.

Summary: The ocean ranch environment contains ultra-low-frequency wave energy that can be utilized for powering low-power equipment. Therefore, this article proposes a smart ocean ranch self-powered and self-monitoring system (SOR-SSS) which consists of several key components: a mass pendulum ball (MPB), a commutation wheel system (CWS), an electromagnetic energy harvesting unit (EEHU), and four piezoelectric energy harvesting units (PEHU). Through six-degree-of-freedom vibration test bench experiments, the SOR-SSS achieved a maximum output power of 17.56 mW under a working condition of 0.4 Hz, which was sufficient to power 152 LED lights. Additionally, by training the experimental base data using the LSTM algorithm, two different tasks were trained with a maximum accuracy of 99.72% and 99.80%, respectively. These results indicate that the SOR-SSS holds significant potential for collecting and predicting ultra-low-frequency blue energy. It can provide an effective energy supply and monitoring solution for smart ocean ranch.

Summary: A crucial challenge in hydrogen production through electrolysis is developing inexpensive, earth-abundant, and highly efficient Pt-free electrocatalysts for the hydrogen evolution reaction (HER). Molybdenum carbide is ideal for this application because of its special electrical structure, low cost, and advantageous characteristics. Herein, the long-lived electrocatalysts for HER have been synthesized via the direct current (DC) arc discharge plasma method under ambient air conditions, and the relationship between the properties of materials and catalytic characteristics has been established. The samples differed in the ratio of molybdenum, graphite, and melamine. The sample with the highest proportion of melamine in the initial mixture has Mo2C-MoO2 heterointerfaces, which demonstrates the highest and most stable electrocatalytic activity with the overpotential of 148 mV at 10 mA·cm-2 and Tafel slope of 63 mV·dec−1 in alkaline electrolyte. Meanwhile, the electrodes demonstrated long-lived electrochemical durability for two weeks and investigated the features of forming a stable system for HER.