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Describes a study that used a teaching strategy based on two teaching experiments which could facilitate students' conceptual understanding of electrochemistry. Involves two sections (n=29 and n=28) of 10th grade high school students in Venezuela. Concludes that the teaching experiments facilitated student understanding of electrochemistry. (Author/SOE)

A previous study of prospective teachers found that students from different countries and different levels of electrochemistry hold common misconceptions, indicating that concepts were presented to them poorly. Reports on how prospective teachers' scientifically incorrect ideas were used to form assertion-reason-type questions and how these questions were used to identify previously unreported conceptual difficulties related to these ignored concepts. (Author/MM)

Describes a concrete teaching model designed to eliminate students' misconceptions about current flow in electrochemistry. The model uses a semi-permeable membrane rather than a salt bridge to complete the circuit and demonstrate the maintenance of cell neutrality. Concludes that use of the model led to improvement in students' understanding at the high school and university levels. (Contains 27 references.) (WRM)

Investigates the effects of both computer animations of microscopic chemical processes occurring in a galvanic cell and conceptual-change instruction based on chemical demonstrations on students' conceptions of current flow in electrolyte solutions. Finds that conceptual change instruction was effective at dispelling student misconceptions but computer animations did not appear to affect student test responses. (Contains 36 references.) (Author/WRM)

Examines textbooks used in college-level chemistry courses for misleading or erroneous statements leading to student misconceptions about electrochemistry. (CCM)

Examines students' misconceptions and proposed mechanisms related to current flow in electrolyte solutions and the salt bridge. Confirms reported misconceptions and identifies several new ones. Discusses probable sources of misconceptions and some methods for preventing them. Contains 27 references. (JRH)

Describes a demonstration of the principles of a voltaic cell using lemon cells to power a calculator and other items. A lemon fortified with a penny and a galvanized nail produces a potential of one volt. (PVD)

Electrochemical interfaces are central to the function and performance of energy storage devices. Thus, the development of new methods to characterize these interfaces, in conjunction with electrochemical performance, is essential for bridging the existing knowledge gaps and accelerating the development of energy storage technologies. Of particular need is the ability to characterize surfaces or interfaces in a non-destructive way with adequate resolution to discern individual structural and chemical building blocks. To this end, sub-diffraction-limit low-energy infrared optical probes that exploit near-field interactions within atomic force microscopy platforms, such as pseudoheterodyne nanoimaging, photothermal nanoimaging and nanospectroscopy, and nanoscale Fourier transform infrared spectroscopy, are all powerful emerging techniques. These are capable of non-destructive surface probing and imaging at nanometer resolution. This review outlines recent efforts to characterize ex situ,in situ,andoperando electrode materials and electrochemical interfaces in rechargeable batteries with these advanced infrared near-field probes.

Water structure near electrode interfaces may play an important role in controlling CO2 electroreduction. Using plasmon-enhanced vibrational sum frequency generation spectroscopy, we demonstrate the emergence of an interfacial water subpopulation with large electric fields along their OH bonds, when Na2CO3 ions are present near the electrode under applied potential. With molecular dynamics simulations, we show that the approach of aqueous Na2CO3 to electrodes is coupled to the formation of structured and oriented ion complexes, and that the emergent water population is associated with the first solvation shell of these complexes. This water subpopulation is seen even when the sole source of CO32− is its in-situ generation from CO2, indicating that the interfacial species investigated here are likely ubiquitous in CO2 electroreduction contexts.

Current models to understand the reactivity of metal/aqueous interfaces in electrochemistry, e.g., volcano plots, are based on the adsorption free energies of reactants and products, which are often small hydrophobic molecules (such as in CO2 and N2 reduction). Calculations played a major role in the quantification and comprehension of these free energies in terms of the interactions that the reactive species form with the surface. However, solvation free energies also come into play in two ways: (i) by modulating the adsorption free energy together with solute–surface interactions, as the solute has to penetrate the water adlayer in contact with the surface and get partially desolvated (which costs free energy); (ii) by regulating transport across the interface, i.e., the free energy profile from the bulk to the interface, which is strongly non-monotonic due to the unique nature of metal/aqueous interfaces. Here, we use constant potential molecular dynamics to study the solvation contributions, and we uncover huge effects of the shape and orientation (on top of the already known size effect) of small hydrophobic and amphiphilic solutes on their adsorption free energy. We propose a minimal theoretical model, the S.O.S. model, that accounts for size, orientation, and shape effects. These novel aspects are rationalized by recasting the concepts at the base of the Lum–Chandler–Weeks theory of hydrophobic solvation (for small solutes in the so-called volume-dominated regime) into a layer-by-layer form, where the properties of each interfacial region close to the metal are explicitly taken into account. [ABSTRACT FROM AUTHOR]

Many applications involving plasma–liquid interactions depend on the reactive processes occurring at the plasma–liquid interface. We report on a falling liquid film plasma reactor allowing for in situ optical absorption measurements of the time-dependence of the ferricyanide/ferrocyanide redox reactivity, complemented with ex situ measurement of the decomposition of formate. We found excellent agreement between the measured decomposition percentages and the diffusion-limited decomposition of formate by interfacial plasma-enabled reactions, except at high pH in thin liquid films, indicating the involvement of previously unexplored plasma-induced liquid phase chemistry enabled by long-lived reactive species. We also determined that high pH facilitates a reduction-favoring environment in ferricyanide/ferrocyanide redox solutions. In situ conversion measurements of a 1:1 ferricyanide/ferrocyanide redox mixture exceed the measured ex situ conversion and show that conversion of a 1:1 ferricyanide/ferrocyanide mixture is strongly dependent on film thickness. We identified three dominant processes: reduction faster than ms time scales for film thicknesses >100 µm, •OH-driven oxidation on time scales of <10 ms, and reduction on 15 ms time scales for film thickness <100 µm. We attribute the slow reduction and larger formate decomposition at high pH to HO 2 − formed from plasma-produced H2O2 enabled by the high pH at the plasma–liquid interface as confirmed experimentally and by computed reaction rates of HO 2 − with ferricyanide. Overall, this work demonstrates the utility of liquid film reactors in enabling the discovery of new plasma-interfacial chemistry and the utility of atmospheric plasmas for electrodeless electrochemistry. [ABSTRACT FROM AUTHOR]

Research interests in two-dimensional (2D) materials have seen exponential growth owing to their unique and fascinating properties. The highly exposed lattice planes coupled with tunable electronic states of 2D materials have created manifold opportunities in the design of new platforms for energy conversion and sensing applications. Still, challenges in understanding the electrochemical (EC) characteristics of these materials arise from the complexity of both intrinsic and extrinsic heterogeneities that can obscure structure-activity correlations. Scanning EC probe microscopic investigations offer unique benefits in disclosing local EC reactivities at the nanoscale level that are otherwise inaccessible with macroscale methods. This review summarizes recent progress in applying techniques of scanning EC microscopy (SECM) and scanning EC cell microscopy (SECCM) to obtain distinctive insights into the fundamentals of 2D electrodes. We showcase the capabilities of EC microscopies in addressing the roles of defects, thickness, environments, strain, phase, stacking, and many other aspects in the heterogeneous electron transfer, ion transport, electrocatalysis, and photoelectrochemistry of representative 2D materials and their derivatives. Perspectives for the advantages, challenges, and future opportunities of scanning EC probe microscopy investigation of 2D structures are discussed.

Enantio-discrimination and spin-dependent electrochemistry (SDE), as a manifestation of the chirality-induced spin selectivity (CISS) effect, are important phenomena that can be probed by "chiral" electrochemistry. Here, we prepared chiralized surfaces of gold and nickel, to serve as working electrodes, through effective chemisorption of enantiopure dimethyl-bis(ethylenedithio)-tetrathiafulvalene (DM-BEDT-TTF) 1, tetramethyl-bis(ethylenedithio)-tetrathiafulvalene (TM-BEDT-TTF) 2, and their capped silver nanoparticle (AgNPs) aggregate by simple incubation of the metallic substrates. The effective chemisorption was checked by means of ultrahigh vacuum x-ray photoelectron spectroscopy (XPS) and by electro-desorption experiments, i.e., cyclic voltammetry (CV) scans showing a first electro-desorption peak at about −1.0 V. The Au|1 and Au|2 chiral electrodes were successfully used in CV experiments exploiting chiral redox probes. Finally, the hybrid interfaces Ni|enantiopure 1 or 2|AgNPs served as working electrodes in SDE experiments. In particular, the hybrid chiral interfaces Ni|(R)-2|AgNPs and Ni|(S)-2|AgNPs exhibited a significant spin-filtering ability, as a manifestation of the CISS effect, with average spin polarization values of 15%. [ABSTRACT FROM AUTHOR]

Electron transfer in the electrode–solution interface is responsible for the signal in the electrochemical sensor. However, the Electrical Double-Layer (EDL) characteristic is usually ignored in signal modeling. Here, we constructed a model based on the reaction–diffusion equation to describe the dynamics in the EDL during sensing. With this model, many common experimental phenomena, such as transient/steady-state current variation or detection nonlinearization, can be unraveled by exploring the effects of position, kinetics proportionality coefficient (k), and reaction order (β). We also put forward some suggestions to improve the stability and linear detection range for future sensor design. [ABSTRACT FROM AUTHOR]

Fluorinated organic compounds (FOCs) represent a class of synthetic chemicals distinguished by their resilient carbon–fluorine bonds, which demonstrate an ability to withstand environmental degradation over an extended period. The integration of FOCs into cutting-edge applications, including lithium-ion batteries (LiBs), presents considerable potential for environmental harm that has not yet been sufficiently addressed. This study focuses on the environmental fate of two fluorinated aromatics, tris(pentafluorophenyl)borane (TPFPB) and tris(pentafluorophenyl)phosphine (TPFPP), given their important role in improving the performance of LiBs. To achieve this, laboratory simulation methods including total oxidizable precursor assay, electrochemistry (EC), Fenton reaction, UV-C irradiation, and hydrolysis were employed. Liquid chromatography and gas chromatography coupled with high-resolution mass spectrometry were used for identification of transformation products (TPs) and prediction of their molecular formulae. Despite the structural similarity between TPFPB and TPFPP, distinct differences in electrochemical behavior and degradation pathways were observed. TPFPB readily underwent hydroxylation and hydrolysis, resulting in a wide range of 49 TPs. A total of 28 TPs were newly identified, including oligomers and highly toxic dioxins. In contrast, TPFPP degraded exclusively under harsh conditions, requiring the development of innovative conditioning protocols for EC. In total, the simulation experiments yielded nine structurally different compounds, including seven previously undescribed, partially defluorinated TPs. This study highlights the potential risks associated with the use of FOCs in LiBs and provides insight into the complex environmental behavior of FOCs. [ABSTRACT FROM AUTHOR]

The production of hydrogen via green method is the need of the present time to overcome the world's energy demand. Several electrocatalysts were employed to study critical oxygen evolution process (OER), and, Hydrogen evolution process (HER), which are designed for water splitting to generate clean hydrogen fuel. Here, we used a low-cost approach to fabricate NiS/MoTe 2 , which resulted in increased catalytic activity for water splitting. The nanocomposite's unique structure provides a larger surface area of 94 m2 g−1, evaluated from BET technique, resulting in more active sites with enough charge transfer capacity and material stability over time. The composite material has a synergistic impact with improved active sites, resulting in a much-reduced overpotential of 274, and, 180 mV for OER, and, HER at 10 mA cm−2 current density, respectively. It also has a lower Tafel value of 48, and, 47 mV dec−1, indicating efficient charge transfer during OER process and high electrocatalytic activity on Nickel Foam electrode. Water electrolysis's enhanced efficiency is due to huge surface area, higher mass activity for 4 and 3.84 A g−1 for OER and HER, respectively. NiS/MoTe 2 has lower Rct of 219 mΩ and 36.2 Ω, and it shows conductivity of 0.0084, and, 0.0082 S m−1 for OER, and HER, respectively. The synthesized material has enhanced ionic conductivity of 0.0084 and 0.0082 S m−1 for OER, and HER, accordingly. This advancement has potential to simplify electron transfer and usher in a new age by providing an improved alternative for noble metal-based materials. [Display omitted] • A simple Hydrothermal approach for the synthesis of material was opted. • Electrocatalyst showcased smaller overpotentials of 274 and 180 mV, for OER and HER, respectively. • A smaller Tafel slope values of 48 and 47 mV/dec for OER and HER was observed, respectively. • The catalyst remained stable up to 50 h for both OER and HER. [ABSTRACT FROM AUTHOR]

Electrode materials based on zinc molybdenum oxides were designed by the saccharide-assisted sol-gel procedure for electrochemical hydrogen storage (EHS). By using different characterization methods to observe the formation of nanostructures, it was possible to determine that carbon texture was present on the nanostructured surfaces of zinc molybdenum oxides. The effects of employing various saccharides (mono, di, and poly saccharides) as carbon sources and fuel on the microstructure, electrochemical behaviors, and purity of synthesized samples were compared. The growth of nanocomposites including Zn 2 Mo 3 O 8 , ZnMo 8 O 10 , and Mo 8 O 23 phases was facilitated by the saccharide. A charge-discharge method was used to build three-electrode cells and expose them to galvanostatic cycling. To ascertain the stability of electrode architectures, cycling performance at various rates was carried out. The samples' hydrogen storage capabilities were examined, and the sample generated with glucose showed an optimum capacity about 1017 mAhg−1 after 15th cycle. • Saccharide assisted sol-gel synthesis of carbonous zinc molybdate nanocomposites as electrode materials. • Investigation of crystallinity, microstrain and structural parameters. • The assessment of hydrogen storage activity using comparative chronopotentiometry study. • Understanding of redox and physisorption-based efficient storage mechanisms. [ABSTRACT FROM AUTHOR]

The development of cost-effective and highly efficient electrocatalysts is critical to help electrochemical non-enzymatic sensors achieve high performance. Here, a new class of catalyst, Ru single atoms confined on Cu nanotubes as a single-atom alloy (Ru1Cu NTs), with a unique electronic structure and property, was developed to construct a novel electrochemical non-enzymatic glucose sensor for the first time. The Ru1Cu NTs with a diameter of about 24.0 nm showed a much lower oxidation potential (0.38 V) and 9.0-fold higher response (66.5 μA) current than Cu nanowires (Cu NWs, oxidation potential 0.47 V and current 7.4 μA) for glucose electrocatalysis. Moreover, as an electrochemical non-enzymatic glucose sensor, Ru1Cu NTs not only exhibited twofold higher sensitivity (54.9 μA mM−1 cm−2) and wider linear range (0.5–8 mM) than Cu NWs, but also showed a low detection limit (5.0 μM), excellent selectivity, and great stability. According to theoretical calculation results, the outstanding catalytic and sensing performance of Ru1Cu NTs could be ascribed to the upshift of the d-band center that helped promote glucose adsorption. This work presents a new avenue for developing highly active catalysts for electrochemical non-enzymatic sensors. [ABSTRACT FROM AUTHOR]

Nanozymes are a class of nanomaterials with biocatalytic function and enzyme-like activity, whose advantages include high stability, low cost, and mass production. They can catalyze the substrates of natural enzymes based on specific nanostructures and serve as substitutes for natural enzymes. Their applied research involves a wide range of fields such as biomedicine, environmental governance, agriculture, and food. Molecular logic gates are a new cross-disciplinary discipline, which can simulate the function of silicon circuits on a molecular scale, perform single or multiple input logic operations, and generate logic outputs. A molecular logic gate is a binary operation that converts an input signal into an output signal according to the rules of Boolean logic, generating two signals, a high level, and a low level. The high and low levels represent the "true" and "false" values of the logic gates, and their outputs correspond to "l" and "0" of the molecular logic gates, respectively. The combination of nanozymes and logic gates is a novel and attractive research direction, and the cross-application of the two brings new opportunities and ideas for various fields, such as the construction of efficient biocomputers, intelligent drug delivery systems, and the precise diagnosis of diseases. This review describes the application of logic gates based on nanozymes, which is expected to provide a certain theoretical foundation for researchers' subsequent studies. [ABSTRACT FROM AUTHOR]