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Hydrogen production from electrochemical water dissociation has been considered as a facile and promising approach to address energy related crisis in the world. In this regard, development of high performance, stable, and cost-effective catalysts for full water splitting is highly demanded. In this work a high performance electrocatalyst based on commercially available Tin oxide nanoparticles mixed with carbon nanotubes (CNT) is presented for electrocatalytic water splitting. The catalyst prepared through facile dropped casting method and obtained a high electrocatalytic activity for full water splitting. One of the key important parameters in water splitting is producing hydrogen/oxygen at high rate under long term stability. This is problematic because it would result in catalyst degradation and performance fallen. However, herein, the prepared electrocatalyst demonstrated a high stability of more than 10 h operation under a high applied current density of 100 mA.cm−2 for hydrogen evolution reaction. For the both hydrogen and oxygen, the prepared catalyst (SnO 2 /CNT coated on carbon paper) delivered the current density of 10 mA.cm−2 at a low overpotentials of 150 mV and 250 mV, respectively. Our observations validate the excellent capability in significantly modifying the catalytic activity of transition metal compound catalysts with carbon nanostructures. [Display omitted] • A synergetic effect of CNT and SnO 2 combination on the electrocatalytic performance was observed. • A lower overpotentials required to reach high current densities, along with high stability at high current. • CNT hybridization with SnO 2 influenced the Volmer step of HER. Also, the adsorption of oxygen and hydrogen affected. • The open structure accelerated the gas detachments during OER or HER, influencing the performance of the system. [ABSTRACT FROM AUTHOR]

Cobalt (Co) is the interconnect metal of integrated circuits with the feature size of 10 nm and below, and Co corrosion is the main problem in cobalt interconnect chemical mechanical polishing (CMP). The introduction of inhibitors is one of the most ideal approaches to reduce corrosion. In this work, useful insights into the corrosion inhibition performance of nicotinic acid (NA), a green inhibitor, on cobalt film in alkaline medium were investigated via electrochemical characterization, surface analysis, quantum chemical calculation, and molecular dynamics (MD) simulation, as well as the adsorption mechanism at atomic level was explored. NA belongs to anodic erosion inhibitor and its inhibition efficiency reached a maximum of 86.65 % at the concentration of 80 mM pH 10, which was identified by the contact angle and potentiodynamic polarization (PDP) test. The electrochemical impedance spectra (EIS) suggested that the surface resistance was enhanced to prevent corrosion. Free energy obtained from the Langmuir model indicates that NA molecules are physically and spontaneously adsorbed on cobalt surface. XPS results further confirmed this point, which reveals that NA exists in the form of Nic2− in alkaline solution and forms a Co(OH) 2 (Nic2-) molecule group (Co(II)-NA) on Co surface. Additionally, quantum chemical calculations based on density function theory (DFT) have approved that C N bond and carboxyl group are the active sites of NA molecule and form the most significant electrostatic adsorption force with cobalt atoms. Moreover, it can be inferred from MD simulations that NA molecules are spontaneously and physically adsorbed on the cobalt surface at a certain angle. In a word, NA manifests its effectiveness in corrosion inhibition of cobalt and will become a potential cobalt CMP inhibitor. The research methods and results of this paper are beneficial to the study of the adsorption characteristics and inhibition mechanism of inhibitors on the metal surface, and provide a theoretical basis for optimizing the composition of Co CMP slurry. The major mechanism of corrosion inhibition effect by nicotinic acid (NA) is to form a passivation film which adsorbs on cobalt (Co) surface so as to strengthen the surface impedance and isolate the corrosion medium. In an alkaline environment (pH 10), NA exists in the form of Nic2− ions, which are negatively charged. Driven by electrostatic forces and Van der Waals forces between NA molecule (N atom and the carboxyl) and cobalt atom, Nic2− ions are appealed to the Co(OH) 2 , leading to the appearance of Co(II)-NA molecule groups. NA molecules produce a single or multilayer self-assembled Co(II)-NA film on the cobalt surface and further prevent the corrosion on Co film. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis, characterization and spectroelectrochemical properties of new triphenylamine-benzoxazine systems. • Determination of the electrochemical oxidation dimerization mechanism of triphenylamine-benzoxazine systems. • Design of a simple methodology to control the crosslink process based on spectroelectrochemical techniques. Polybenzoxazines attract much attention as good phenolic resins due to their interesting and useful properties. Recently, benzoxazine monomers have been employed as crosslinking agents to enhance the properties of different types of polymers by being used as additives to a secondary cure process. In this paper, we propose a new electroinduced approach to increase the crosslinking density of electroactive polybenzoxazines through the design of new monomers that contain triphenylamine groups as electrodimerization points. The use of electrochemical techniques means the crosslinking process can be monitored and also the electrochemical reaction process upon polybenzoxazine oxidation either in solution or ionogel matrixes can be disclosed. These studies lay the foundations for the design of smart polybenzoxazines that could undergo dual-cure mechanisms at low electrochemical potential values. [ABSTRACT FROM AUTHOR]

• Effects of chemical factors on flotation. • International Mineral Processing Congresses since 1952. • Contributions by research groups from around the world. • Reagents, mechanisms, hydrophobic force, hemimicelles, electrochemistry. • Instrumental methods in flotation research. Since the 1st IMPC took place in London in 1952 there have been many developments in our understanding of flotation both in terms of chemical and physical factors influencing the process. Many of these developments have been captured in the Proceedings of the Congresses that have taken place since that first event as well as in numerous journal papers and special volumes dedicated to flotation. This paper attempts to highlight the individual contributions which many eminent researchers and engineers have made over the past 70 years towards extending our understanding of especially the effects of chemical factors on flotation. Although the focus is mainly on more fundamental aspects it seems that the 'pull' of practice has often preceded the 'push' from laboratory-based research. As the fundamental understanding of the role of chemical factors on flotation continues to be developed the major challenge remains to transfer effectively this knowledge into the domain of operations of this profoundly complex process. [ABSTRACT FROM AUTHOR]

This paper represents a comprehensive review about the most recent developments in indium tin oxide (ITO) based electrochemical chemosensors and biosensors. ITO electrode has received increasing attention due to its large potential window and excellent optical properties. It provides electrochemical stability and a low background current and has recently been applied as a working electrode in the electrochemical analysis. The focal point of this paper was based on the sensor applications and properties of modified ITO electrodes in the determination of some biomarkers, pathogens, pesticides, drugs, organic species, and metals, etc. by electrochemical techniques. Experimental conditions and some analytical parameters of the electrode applications were discussed. The future possibilities and prospects of ITO electrodes have been outlined. In this case, there are significant studies to display the powerful ITO sensors for the determination of analytes and this review summarizes the available data on this topic between 2010 and 2021. • Recent developments on modified ITO electrodes were reviewed. • The modification strategies of ITO electrodes were summarized. • Sensor applications of modified ITO electrodes for some drugs, pesticides, and organic species were reviewed. • Recent research on the modified ITO electrodes based diagnostic applications was summarized. [ABSTRACT FROM AUTHOR]

• A novel ferrcenyl imine nickel complex was synthesized and characterized. • The cyclic voltammetry and the polarization curves have been performed. • The electron transfer capability and diffusion behavior have been studied. • The studied compound was screened for its electrocatalytic activity. • The indirect electrocatalytic reduction of ethylhalogenoacetates has been studied. This paper explores the synthesis, characterization and electrocatalytic behavior of a new ferrocenyl-substituted tetradentate Nickel Schiff base complex. The complex, N,N-Bis[5-(N,N-ferrocenmethylaminophenyl)methylsalicylidyne]-1,2-diaminoethane of nickel(II) ((Fc-Me-Ani) 2 -LNiII), was prepared by heating the tetradentate Schiff base ligand ((Fc-Me-Ani) 2 -H 2 L) in the presence of a stoichiometric amount of tetrahydrate nickel(II) acetate salt, dissolved in a mixture of ethanol and methylene chloride at 50°C under N 2 atmosphere. The molecular structure of the complex was deduced from elemental analysis, FT-IR, UV-Vis and mass spectrometry. The electrochemical characterization was investigated by cyclic voltammetry on a glassy carbon electrode and the effect of the solvent (methylenechloride (DCM), dimethylformamide (DMF) and dimethylsulfoxide (DMSO)) was analyzed. The electrochemical characterization of the nickel complex reveals the electron-transfer capability of the two electroactive redox moieties, ie. the ferrocenyl moieties (Fc+‏/Fc) and the metallic centre (Ni2+/Ni+). The diffusion coefficient (D) and the standard rate constant (K0) have also been calculated from the cyclic voltammetry and the polarization curves of ferrocenyl redox process. So, they are influenced by both used method and medium. Cyclic voltammetry has also been performed to examine the performances of the electrocatalytical reduction reaction towards two alkylhalides like ethyl chloroacetate and ethyl bromoacetate in DMF solution. The current increase and the cathodic shift of the Ni2+→Ni+ reduction process in the presence of increasing concentrations of these alkyl halides evidence the catalytic effect of the (Fc-Me-Ani) 2 -LNiII complex in the reduction of these compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper describes the synthesis of two sulfonamides (NethylS and NpropylS) differing in the length of the alkylamino substituent. Their physicochemical characteristics are discussed, with particular emphasis on the electrochemical profile, acid-base character, and complexing ability towards trivalent rhodium and ruthenium ions. [Display omitted] Two sulfonamide derivatives differing in the length of alkylamino substituent (NethylS and NpropylS) had been synthesized and then their structure and physicochemical properties were the subject of our extensive research. The complete spectroscopic and electrochemical profiles of studied compounds together with their ionic species assignment were established as well as reported. The electrochemical characteristics of sulfonamides were examined in both aqueous and aprotic solvents using cyclic voltammetry (CV) and differential pulse voltammetry technique (DPV). Furthermore, the pH effect on the NethylS/NpropylS redox processes and spectroscopic properties were also studied. The p K a values of compounds were determined using the combined pH-spectrophotometric (micro)titration method. The activity of studied sulfonamide antibiotics was verified by binding them into complexes with d-block metal ions, for which the complexing properties of both NethylS and NpropylS towards ruthenium(III) and rhodium(III) ions as well as their corresponding stability constants were determined. [ABSTRACT FROM AUTHOR]

[Display omitted] • Seven examples of 2-(1,5-diaryl-4,5-dihydro-1 H -pyrazol-3-yl)phenols are synthesized. • Photophysical/Electrochemical properties of fluorescent 2-pyrazolines are studied. • The UV–Vis absorption/emission properties are performed in five solvents. • ESIPT effect and donor-acceptor substituent influence are investigated in detail. • The fluorescence lifetimes (TCSPC) increase according to the solvent polarity. This paper describes the synthesis, structural study, and evaluation of electrochemical and photophysical properties by UV–Vis absorption and fluorescence emission analysis (solution and solid-state) of a series of eight 3,5-aryl-substituted 1-phenyl-2-pyrazolines (5), where 3-aryl = 2-OH-C 6 H 4 (5a-g) or Ph (5h), and 5-aryl = Ph (a , h), 1-naphthyl (b), 4-Br-C 6 H 4 (c), 4-F-C 6 H 4 (d), 4-OCH 3 -C 6 H 4 (e), 4-NO 2 -C 6 H 4 (f), 4-(N(CH 3) 2)-C 6 H 4 (g). The UV–Vis absorption properties of 2-pyrazolines were evaluated in DCM, MeCN, AcOEt, EtOH, and DMSO as the solvent and showed a fluorescence shift for the polar aprotic solvents. The steady-state fluorescence emission exhibited a band in the blue region when excited at the least energetic transition of each compound, although the excited-state intramolecular proton (ESIPT) effect was not detected. In the solid state, compounds presented similar behavior regarding absorption and emission properties compared to the solution assays. With the electrochemical analyses performed for the synthesized 2-pyrazolines, it was possible to conclude that the redox potentials were influenced by the electronic and steric effects of the substituents on the aryl rings and, according to the electronic nature of the substituents, which electron-donating groups were favored. Finally, the TD-DFT analyses revealed that all compounds had delocalized electron density throughout the 2-pyrazolines unit and were not influenced by the substituent bonded at C-5. Nonetheless, LUMO orbital analysis showed that only derivatives 5b and 5f have this localized density over the substituents. [ABSTRACT FROM AUTHOR]

[Display omitted] Two-dimensional (2D) transition metal carbide/nitride (MXene) has been a hot topic of research since it was proposed in 2011. Etching methods to obtain MXene from MAX phase have been continuously investigated. The excellent hydrophilicity, conductivity and tunability make MXene widely used in electrochemistry. In addition, the development of wearable sensors has promoted the research of conductive hydrogels, and improving the performance of conductive hydrogels is still an area of effort for researchers. Therefore, the incorporation of MXene into hydrogel systems will result in significant improvements in performance. This paper reviews the etching methods of MXene, the synthesis strategies and applications of MXene conductive hydrogels, and provides an outlook on the future development of MXene and MXene conductive hydrogels. [ABSTRACT FROM AUTHOR]

The oxygen-evolution reaction (OER) is pivotal in many energy-conversion technologies as it is an important counter reaction to others that convert stable chemicals to higher-value products using electrochemistry. The local microenvironment and pH for the anode OER can vary from acidic to neutral to alkaline depending on the system being explored, making definitive mechanistic insights difficult. In this paper, we couple experiments, first-principles calculations based on density functional theory, microkinetics, and transport modeling to explore the entire pH range of the OER. At low current densities, neutral pH values unexpectedly perform better than the acidic and alkaline conditions, and this trend is reversed at higher current densities (> 20 mA cm−2). Using multiscale modeling, this switch is rationalized by a change from a dual-reaction mechanism to a single rate-determining step. The model also shows how the alkaline reaction rates dominate in the middle to high pH range. Furthermore, we explore that the local pH for near-neutral conditions is much different (e.g., 2.4 at the reaction surface vs. 9 in the bulk) than the pH extremes, demonstrating the criticality that transport phenomena plays in kinetic activity. [ABSTRACT FROM AUTHOR]

• Electrochemical behavior of Co(III)-catalyzed gold thiosulfate leaching was studied. • Co(NH 3) 6 3+ showed higher coulombic efficiencies of gold dissolution than Cu(NH 3) 4 2+. • Co(NH 3) 6 3+ achieved continuous gold leaching with much reduced S 2 O 3 2− consumption. • Stable mixed ligand complexes of Co2+ with ammonia and thiosulfate were formed. • The cycle between Co(NH 3) 6 3+ and Co(NH 3) x (S 2 O 3)0 (x = 4, 5) played the catalytic role. Thiosulfate is a green gold lixiviant that has promise to replace cyanide at the gold mining industry. Hexaamminecobalt(III) (Co(NH 3) 6 3+) is effective in catalyzing the thiosulfate leaching of gold from ores, but the electrochemical behavior and catalytic leaching mechanisms remain unclear. This paper reports an in-depth investigation into the electrochemical behavior of gold leaching in ammoniacal thiosulfate solutions catalyzed by Co(NH 3) 6 3+. The electrochemical results suggested that Co(NH 3) 6 3+ is more efficient than Cu(NH 3) 4 2+ in catalyzing the ammoniacal thiosulfate leaching of gold. Compared with Cu(NH 3) 4 2+, the coulombic efficiency of gold dissolution (Q Au / Q T) under the Co(NH 3) 6 3+ catalysis is much higher. In the presence of Co(NH 3) 6 3+, the Q Au / Q T was nearly 100% at 150–250 mV and higher than 78.9% at 250–350 mV; at 250 mV, the Q Au / Q T was approximately 100% in the initial electrolysis of 300 s and remained basically unchanged at around 75% after 1200 s. Leaching results further showed that the catalysis of Co(NH 3) 6 3+ not only achieved a continuous leaching of gold with time, but also significantly decreased the consumption of thiosulfate from 36.5% (for Cu(NH 3) 4 2+) to 20.9% after leaching 24 h. In the ammoniacal thiosulfate solution, Co(NH 3) 6 3+ is likely reduced to mixed ligand Co(II) complexes of Co(NH 3) x (S 2 O 3)0 (x = 4, 5), which are readily oxidized back to Co(NH 3) 6 3+. Thus, an improved catalytic mechanism of gold leaching is proposed that the redox cycle between Co(NH 3) 6 3+ and Co(NH 3) x (S 2 O 3)0 (x = 4, 5) catalyzes the leaching of gold with ammoniacal thiosulfate. [Display omitted] [ABSTRACT FROM AUTHOR]

Models that consistently couple particle, electrode, and battery level mechanics and electrochemistry are rare in literature. Within a battery, there are hundreds of layers of electrodes and the inherent multiscale structure of electrodes makes battery level simulations computationally very expensive. This paper presents a multiscale homogenization method that couples mechanics and electrochemistry at the particle, electrode, and battery scales. The method is divided into two parts. Firstly, an electrochemical/mechanical model for a one-dimensional periodic element is applied to determine particle and electrode layer swelling as functions of time and position. Secondly, the layered structure of the battery is homogenized by the use of three-dimensional laminate theory. The homogenized material model can be applied in finite element calculations on the battery level. Layer level stresses can in a second step be back-calculated. The accuracy and efficiency of the method are demonstrated by comparisons to detailed finite element computations where each layer is individually modeled. Predictions of electrode layer stresses are also favorably compared to impedance measurements of electrode layers at different electrode positions. It is furthermore demonstrated that the effects of external battery loadings like battery stacks, casings, and external pressure easily can be captured by the model. • A multiscale homogenization method is presented. • Application of three-dimensional laminate theory to battery modeling. • Layer level stresses are back-calculated from the homogenized model. • Good agreements to detailed finite element computations and experiments. • Efficient method for battery level simulations. [ABSTRACT FROM AUTHOR]

Schematic illustration of electrochemical detection biosensor of exosomes based on C 60 -Au-Tb as signal marker. [Display omitted] • A novel approach based on C 60 -Au-Tb for exosome detection is developed for the first time. • The limit of detection of this sensor is as low as 2.67 × 104 exosomes/mL. • The proposed sensor has the advantages of high sensitivity, high selectivity, simplicity and low cost. • This strategy may hold great potential in biomedical research and clinical diagnosis. As a new serum biomarker, the sensitive detection of exosomes is significant for the early diagnosis of diseases. In this paper, a novel electrochemical biosensor for the sensitive detection of exosomes was constructed utilizing a novel C 60 hybrid as a tracer. Firstly, the epidermal growth factor receptor (EGFR) antibody was immobilized on the electrode surface via Au-NH 2 bonding with Nafion AuNPs substrate. After specific capture of exosomes, C 60 -Au-Tb was grafted onto the surface of exosomes through "carboxyl-Zr4+-phosphate" chemistry, causing a change in the current signal. Under the optimal conditions, there was a linear relationship between the SWV signal and the logarithm of exosomes concentration from 5 × 104 exosomes/mL to 5 × 109 exosomes/mL, and the detection limit was 2.67 × 104 exosomes/mL. In addition, the biosensor had the advantages of high specificity, strong anti-interference ability, good repeatability, and stability. In conclusion, this method had great potential in diagnosing early cancers associated with exosomes. [ABSTRACT FROM AUTHOR]

• Nitrogen-doped carbon-based materials have been recently explored as promising electrocatalysts for N 2 fixation. • A novel synthesis approach was applied to obtain nitrogen-doped carbon-based materials as an electrocatalyst for N 2 fixation. • These synthesized free-standing electrodes showed superior electrocatalytic performance with respect to powders form. • The free-standing nitrogen-doped carbon based electrodes possess benefits in terms of charge transfer and active sites per electrode surface area. Nitrogen-doped carbon-based materials have been recently explored as promising electrocatalysts for N 2 fixation. Herein, a nitrogen-doped carbon film as a self-standing electrode is synthesized through a novel and scalable strategy. After the film synthesis, a thin layer of Au nanoparticles is deposited, significantly enhancing the performance of such films in electrocatalytic N 2 reduction. Owing to the exposed active sites and unique free-standing structure, it shows desirable performance towards electrochemical N 2 fixation with a high Faradaic efficiency of 6.4 %, and a NH 3 production rate of 18.3 μg h−1 cm−2 at a low given potential of -0.05 V vs. reversible hydrogen electrode. Such performance is superior in comparison with Au-nanoparticles-modified nitrogen-doped carbon powder. Further comparison of nitrogen-doped carbon film and nitrogen-doped carbon powder also demonstrates the benefits of the free-standing structure in comparison to film-based materials in terms of charge transfer and active sites per electrode surface area. A novel nitrogen doped carbon (NDC) and gold deposited on NDC free-standing electrodes was presented for the an efficient electrocatalytic N 2 fixation to NH 3. These free-standing electrodes showed superior performance in the electrocatalytic N 2 fixation to NH 3 with respect to the powder counterparts NDC deposited on carbon paper. [Display omitted] [ABSTRACT FROM AUTHOR]

This review overviews and revalues the role that the electrochemical techniques and the continuously evolving electrode designs play in the tremendous progress experienced by electrochemical biosensing. These aspects are scarcely covered in the recent literature on electrochemical biosensors and are discussed in this article through selected representative examples together with other approaches involving the use of signal amplification strategies, electrocatalytic materials, ratiometric designs or antifouling chemistries. Regarding electrodes, the continuous advances made in screen-printed, micro-, paper-based and flexible and wearable materials are critically overviewed. Concerning electrochemical techniques, the use of selected widely known techniques (electrochemical impedance spectroscopy, stripping voltammetry, and potentiometry) to successfully address different applications in response to current biosensing challenges is highlighted through their smart coupling with new experimental designs, bioreceptors and materials. [ABSTRACT FROM AUTHOR]

• Effects of thermodynamic and kinetic dispersion in surface confined voltammetry. • Distinguishing dispersed from non-dispersed cases by looking at voltammetry data. • Thermodynamic dispersion is usually resolvable for all experiments. • Kinetic dispersion is only resolvable for certain systems under defined conditions. Dispersion, or the distribution of kinetic and thermodynamic parameter values describing a redox reaction, has long been acknowledged as a complicating factor in the analysis of both solution and surface-confined voltammetry experiments. In this tutorial paper, we show how varying levels of dispersion can affect the appearance of the experimental current, mainly illustrating the concept with reference to surface-confined reversible one electron transfer. We focus on three voltammetric techniques, ramped Fourier Transform AC Voltammetry, Purely Sinusoidal Voltammetry and Direct Current Voltammetry, showing the effect the dispersion parameters have on the appearance of the resulting current. We have also implemented an interactive web-based simulation package for comparison of the effects of the various parameters, available here. As modelling dispersion significantly increases the computational burden of simulating voltammetry experiments, making well-informed choices about when to include this effect is essential. To facilitate this, we discuss the intuition for when to include dispersion when fitting experimental voltammetry data, again with reference to the three techniques described above. [ABSTRACT FROM AUTHOR]

Mercury is one of the most common heavy metals and a major environmental pollutant that affects ecosystems. Since mercury and its compounds are toxic to humans, even at low concentrations, it is very important to monitor mercury contamination in water and foods. Although conventional mercury detection methods, including inductively coupled plasma mass spectrometry, atomic absorption spectroscopy, and gas chromatography–mass spectrometry, exhibit excellent sensitivity and accuracy, they require operation by an expert in a sophisticated and fully controlled laboratory environment. To overcome these limitations and realize point-of-care testing, many novel methods for direct sample analysis in the field have recently been developed by improving the speed and simplicity of detection. Commonly, these unconventional sensors rely on colorimetric, fluorescence, or electrochemical mechanisms to transduce signals from mercury. In the case of colorimetric and fluorescent sensors, benchtop methods have gradually evolved through technology convergence to give standalone platforms, such as paper-based assays and lab-on-a-chip systems, and portable measurement devices, such as smartphones. Electrochemical sensors that use screen-printed electrodes with carbon or metal nanomaterials or hybrid materials to improve sensitivity and stability also provide promising detection platforms. This review summarizes the current state of sensor platforms for the on-field detection of mercury with a focus on key features and recent developments. Furthermore, trends for next-generation mercury sensors are suggested based on a paradigm shift to the active integration of cutting-edge technologies, such as drones, systems based on artificial intelligence, machine learning, and three-dimensional printing, and high-quality smartphones. [ABSTRACT FROM AUTHOR]