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Common experience with rotting wooden buildings demonstrates that fragmentation is a necessary natural process during biodegradation. In analogy, the loss of structural integrity of biodegradable plastics during biodegradation produces interim microplastic fragments. It is currently not known which parameters govern fragmentation kinetics: chemical structure, physical shape, and composite layers, or composting conditions may all be relevant. Here we investigated the influence of physical shape on the fragmentation of a polyester blend during laboratory tests simulating industrial composting. Methods previously validated on micronized granules as model shape were applied to shapes that better represent consumer products, such as micronized thin films and shredded plastic-coated paper cups. The peak interim number of detected fragments, which are between 3 and 2000 µm, ranked highest for micronized films, lower for micronized plastic granules, and even lower for coated paper cups. The layered structure of polyester on cellulose may thus have stabilized the biodegrading polyester compound against fragmentation. For thin films, fragment counts dissipated with halftime of 2.5 days, and less than 10–8% of the initially added polyester mass was detected in fragments between 3 and 25 µm at the last sampling time point. The physical shape and multilayer structure of the polymer-containing product were found to be decisive for fragmentation kinetics, indicating that tests on micronized polymer granules might not be representative of the release mechanism of fragments from consumer products containing plastic coatings. [ABSTRACT FROM AUTHOR]

This document is a response to a critique of a scientific paper published in Nature Communications. The authors of the response address the criticisms made by Dr. Goldsmith and his colleagues regarding the enzyme activities described in their paper. They clarify that their results were measured using a different method than assumed by Dr. Goldsmith. The authors also present their own experiments that challenge the proposed substrate for one of the enzymes involved in the synthesis of β-ODAP, a compound found in grass peas that can cause a neurodegenerative disorder called lathyrism. They conclude that the synthesis of a key compound involved in β-ODAP synthesis is likely limited in the cytosol of grass pea plants. The article highlights the proposed mechanism for β-ODAP synthesis and provides experimental evidence to support it, while also addressing criticisms and emphasizing the importance of understanding this process for improving the crop. [Extracted from the article]

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The study and modeling of water exchange in complex media using different applications of diffusion and relaxation magnetic resonance (MR) have been of interest in recent years. Most models attempt to describe this process using a first order kinetics expression, which is appropriate to describe chemical exchange; however, it may not be suitable to describe diffusion-driven exchange since it has no direct relationship to diffusion dynamics of water molecules. In this paper, these limitations are addressed through a more general exchange expression that does consider such important properties. This exchange fraction expression features a multi-exponential recovery at short times and a mono-exponential decay at long times, both of which are not captured by the first order kinetics expression. Furthermore, simplified exchange expressions containing partial information of the analyzed system's diffusion and relaxation processes and geometry are proposed, which can potentially be employed in already established estimation protocols. Finally, exchange fractions estimated from simulated MR data and derived here were compared, showing qualitative similarities but quantitative differences, suggesting that the features of the derived exchange fraction in this paper can be partially recovered by employing an existing estimation framework. [ABSTRACT FROM AUTHOR]

Multi-scale predictive models for the shock sensitivity of energetic materials connect energy localization ("hotspots") in the microstructure to macro-scale detonation phenomena. Calculations of hotspot ignition and growth rely on models for chemical reaction rates expressed in Arrhenius forms; these chemical kinetic models, therefore, are foundational to the construction of physics-based, simulation-derived meso-informed closure (reactive burn) models. However, even for commonly used energetic materials (e.g., HMX in this paper) there are a wide variety of reaction rate models available. These available reaction rate models produce reaction time scales that vary by several orders of magnitude. From a multi-scale modeling standpoint, it is important to determine which model best represents the reactive response of the material. In this paper, we examine three global Arrhenius-form rate models that span the range of reaction time scales, namely, the Tarver 3-equation, the Henson 1-equation, and the Menikoff 1-equation models. They are employed in a meso-informed ignition and growth model which allows for connecting meso-scale hotspot dynamics to macro-scale shock-to-detonation transition. The ability of the three reaction models to reproduce experimentally observed sensitivity is assessed by comparing the predicted criticality envelope (Walker–Wasley curve) with experimental data for pressed HMX Class V microstructures. The results provide a guideline for model developers on the plausible range of time-to-ignition that are produced by physically correct Arrhenius rate models for HMX. [ABSTRACT FROM AUTHOR]

Stimulation techniques to enhance fluid pathways are an important tool to make geothermal projects economically feasible. So far, hydraulic stimulation is used almost exclusively for reservoir-wide improvement of the permeability, but induced seismicity poses a challenge. Chemical stimulation on the other hand has been limited to the close vicinity of the borehole and has barely been considered for the creation of enhanced geothermal reservoirs. However, retardation mechanisms reducing the chemical reaction rate can be used to increase the radius of the chemical stimulation thus enabling a reservoir-wide enhancement of fluid pathways. In this work, we review the technologies of retardation mechanisms for chemical stimulation in geothermal systems and identify five groups of retardation techniques: (i) causing impaired mobility of the acid, e.g., by gelling agents; (ii) causing an impaired dissociation, e.g., by the in-situ generation of the reactive compounds; (iii) blocking the mineral surface area, e.g., by alternating injections of pad fluids and acids; (iv) reducing the reaction rate constant, e.g., by cooling; and (v) changing the chemical equilibrium through chelating agents. We found that most applications are currently based on the use of impaired dissociation, but present research focuses on the development and application of chelating agents. Most of these retardation techniques are adopted from the hydrocarbon industry, but there are several techniques that have not been applied in the geothermal context so far for various reasons. We identify a distinctive lack of in-depth descriptions of the retardation techniques in various studies—mostly to protect intellectual property. However, in the light of public concern regarding fracking techniques and to independently assess potential environmental hazards, scientific examination of proposed techniques is indispensable. [ABSTRACT FROM AUTHOR]

The combustion of fuel under intense volumetric forces has the potential to enhance the velocity of flame propagation. To investigate the influence of volumetric forces on the combustion process and the characteristics of flame propagation within fuel, this research paper conducted a numerical analysis of a 2-D rotating pipe subjected to varying volumetric forces. The findings reveal that, within a specific range, an augmentation in volumetric forces progressively elevates both the global and localized speeds of flame propagation. The primary rationale behind the heightened flame propagation speed under intense volumetric forces lies in the fact that the increase in such forces facilitates an enlargement of the interface area between the burned and unburned gases. This, in turn, fortifies the transfer of heat and the chemical reaction rate between the two, effectively shortening the duration of combustion and augmenting the speed of flame propagation. At exceedingly low volumetric forces, the pressure wave generated by combustion in the pipe exerts a certain influence on the speed of flame propagation and the progression of the flame. [ABSTRACT FROM AUTHOR]

This article, titled "Editorial: Plutonium legacy storage and degradation," discusses the safe and secure management of plutonium, a special nuclear material (SNM) that is used in nuclear weapons and can also be used as a fuel for power generation. The article highlights the challenges associated with the storage of separated, unirradiated plutonium, including radiological hazards, proliferation risks, and physical security. It also explores the chemical hazards that can arise from processes such as radiolysis and radioactive decay. The article presents research papers that address the issues of radiolysis, long-term storage, and the conversion of plutonium oxalate to oxide. The goal of this research is to enhance the understanding and management of plutonium for the sake of safety and security. [Extracted from the article]

At present, there is limited research on the application of fuel cell power generation system technology using solid hydrogen storage materials, especially in hydrogen-assisted two-wheelers. Considering the disadvantages of low hydrogen storage capacity and poor kinetics of hydrogen storage materials, our primary focus is to achieve smooth hydrogen ab-/desorption over a wide temperature range to meet the requirements of fuel cells and their integrated power generation systems. In this paper, the Ti0.9Zr0.1Mn1.45V0.4Fe0.15 hydrogen storage alloy was successfully prepared by arc melting. The maximum hydrogen storage capacity reaches 1.89 wt% at 318 K. The alloy has the capability to absorb 90% of hydrogen storage capacity within 50 s at 7 MPa and release 90% of hydrogen within 220 s. Comsol Multiphysics 6.0 software was used to simulate the hydrogen ab-/desorption processes of the tank. The flow rate of cooling water during hydrogen absorption varied in a gradient of (0.02 + x) m s-1 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12). Cooling water flow rate is positively correlated with the hydrogen absorption rate but negatively correlated with the cost. When the cooling rate is 0.06 m s-1, both simulation and experimentation have shown that the hydrogen storage tank is capable of steady hydrogen desorption for over 6 h at a flow rate of 2 L min-1. Based on the above conclusions, we have successfully developed a hydrogen-assisted two-wheeler with a range of 80 km and achieved regional demonstration operations in Changzhou and Shaoguan. This paper highlights the achievements of our team in the technological development of fuel cell power generation systems using solid hydrogen storage materials as hydrogen storage carriers and their application in two-wheelers in recent years. [ABSTRACT FROM AUTHOR]

FeCo2O4/MoS2 binary composite catalysts were prepared by the hydrothermal method and calcination method. In this paper, the morphology and structure of the materials were characterized by means of SEM, EDS, XRD, and XPS. It was found that MoS2 has high activity and good stability in HER, and and it has more prospect than noble metal catalysts. In oxygen evolution chemical kinetics, its rich redox potential allowed it to adsorb OH− on (Co2+/Co3+, Fe2+/Fe3+) and enhanced the activity of OER. The cross-nanosheet structure of the FeCo2O4/MoS2 composite catalyst exposed more catalytic sites and accelerated charge transfer to achieve more efficient mass transfer. FeCo2O4/MoS2 as an anode and cathode was assembled into a two-electrode system in overall water splitting, which showed good catalytic activity. When the composite ratio of FeCo2O4 to MoS2 was 1:0.3, the composite catalyst had the best catalytic activity. The results show that when FeCo2O4/MoS2 is used as a cathode and anode to assemble an alkaline cell, respectively, the voltage for total water electrolysis is 1.59 V at a current density of 10 mA cm−2 in a 1 M KOH electrolyte, it can keep good stability in a 10 h test with electrolyzed water, and its current retention rate is 98.5%. [ABSTRACT FROM AUTHOR]

Titanium tetrachloride (TiCl4) is a well-known source of titanium (Ti) for the formation of titanium nitride (TiN) barrier material in the semiconductor interconnection process; however, the reaction of by-products with airborne molecules can cause unexpected pump trips and equipment breakdown from the by-product powder build-up. Plasma scrubbers are used to decompose by-products, but hydrogen chloride (HCl) and nitrogen oxides are produced during and after the process. The process mechanisms change when the temperature and applied power of the heat source change. In this paper, we study the influence of the reactor temperature and applied power to the heat source on the decomposition capacity of TiCl4 in a plasma pretreatment system (PPS). We examine the effect of the temperature and heat source power to understand the reaction mechanisms for the composition and decomposition of gaseous species with chemical reactions through simultaneous methods. We analyzed the system with computational fluid dynamics (CFD) and chemical kinetic simulation to investigate the changes of the system mechanism. Subsequently, we achieved results for the correlation between the temperature of the reactor, power applied to the heat source, composition and decomposition of species, and chemical reaction mechanisms. [ABSTRACT FROM AUTHOR]

Fe(III) has been proved to be a more effective oxidant than dissolved oxygen at ambient temperature, however, the role of Fe(III) in pyrite acidic pressure oxidation was rarely discussed so far. In this paper, in-situ electrochemical investigation was performed using a flow-through autoclave system in acidic pressure oxidation environment. The results illustrated that increasing Fe(III) concentrations led to raising in redox potential of the solution, and decreased passivation of pyrite caused by deposition of elemental sulfur. Reduction of Fe(III) at pyrite surface was a fast reaction with low activation energy, it was only slightly promoted by rising temperatures. While, the oxidation rate of pyrite at all investigated Fe(III) concentrations increased obviously with rising temperatures, the anodic reaction was the rate-limiting step in the overall reaction. Activation energy of pyrite oxidation decreased from 47.74 to 28.79 kJ/mol when Fe(III) concentration was increased from 0.05 to 0.50 g/L, showing that the reaction kinetics were limited by the rate of electrochemical reaction at low Fe(III) concentrations, while, it gradually turned to be diffusion control with increasing Fe(III) concentrations. [ABSTRACT FROM AUTHOR]

Silicon has dimensional limitations in following Moore's law; thus, new 2D materials complementing Silicon are being researched. Molybdenum disulfide (MoS2) is a prospective material anticipated to bridge the gap to complement Silicon and enhance the performances of semiconductor devices and embedded systems in the package. For a synthesis process to be of any relevance to the industry. it needs to be at the wafer scale to match existing Silicon wafer-processing standards. Atomic Layer Deposition (ALD) is one of the most promising techniques for synthesizing wafer-scale monolayer MoS2 due to its self-limiting, conformal, and low-temperature characteristics. This paper discusses the wafer-scale ALD synthesis of Molybdenum trioxide (MoO3) using Mo (CO)6 as a precursor with Ozone as a reactant. An ALD-synthesized wafer-scale MoO3 thin film was later sulfurized through Chemical Vapor Deposition (CVD) to transform into stoichiometric MoS2, which was evaluated using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). The roles of activation energy and first-order reaction kinetics in determining the ALD recipe parameters of the pulse time, reactor temperature, and purge time are explicitly discussed in detail. Discretized pulsing for developing one-cycle ALD for monolayer growth is suggested. Remedial measures to overcome shortcomings observed during this research are suggested. [ABSTRACT FROM AUTHOR]

In this paper, we explore the deflagration combustion of methane–air mixtures through both experimental and numerical analyses. The key parameters defining deflagration combustion dynamics include maximum explosion pressure (Pmax), maximum rate of explosion pressure rise (dP/dt)max, deflagration index (KG), and laminar burning velocity (SU). Understanding these parameters enhances the process of safety design across the energy sector, where light-emissive fuels play a crucial role in energy transformation. However, most knowledge on these parameters comes from experiments under standard conditions (P = 1 bar, T = 293.15 K), with limited data on light hydrocarbon fuels at elevated temperatures. Our study provides new insights into methane–air mixture deflagration dynamics at temperatures ranging from 293 to 348 K, addressing a gap in the current process industry knowledge, especially in gas and chemical engineering. We also conduct a comparative analysis of predictive models for the laminar burning velocity of methane mixtures in air, including the Manton, Lewis, and von Elbe, Bradley and Mitcheson, and Dahoe models, alongside various chemical kinetic mechanisms based on experimental findings. Notably, despite their simplicity, the Bradley and Dahoe models exhibit a satisfactory predictive accuracy when compared with numerical simulations from three chemical kinetic models using Cantera v. 3.0.0 code. The findings of this study enrich the fundamental combustion data for methane mixtures at elevated temperatures, vital for advancing research on natural gas as an efficient "bridge fuel" in energy transition. [ABSTRACT FROM AUTHOR]

Despite extensive research, the relationship between the progression of the alkali–silica reaction (ASR) and the expansion of concrete due to ASR, particularly for the heterogeneous aggregate with slow reactivity, is not thoroughly understood. In this paper, the dissolution kinetics of reactive silica present in sandstone when exposed to NaOH solutions, alongside the expansion characteristics of rock prisms under ASR conditions, were studied. The experimental results indicate that ASR behaves as a first-order reaction, accompanied by an exponential decrease in the concentration of OH− over time, and the dissolution rate of silica is predominantly governed by diffusion dynamics. Notably, increasing the temperature accelerates ASR, which augments the expansive pressure in a confined and limited space, leading to more significant aggregate expansion. Conversely, higher temperatures also result in a diminished retention of ASR gels within the aggregate, leading to the mitigation of ASR expansion. Our findings underscore that larger aggregates retain a greater quantity of gels, resulting in more pronounced expansion. To establish an ASR prediction model based on the relationship of the ASR expansion of concrete to high and low temperatures, the parameters such as the range of curing temperatures and the grading size of aggregates should be carefully considered for the experiments. [ABSTRACT FROM AUTHOR]

The Trauzl lead block test allows the determination of the approximate performance of explosives in blasting applications by measuring the volume increase (expansion) that is produced by the detonation of an explosive charge in the cavity of a lead block. In this paper, we reconsider the possibility of interpreting the Trauzl test results in terms of detonation parameters or quantities. The detonation parameters used in the analysis are calculated using the thermochemical code EXPLO5, while the hydrocode AUTODYN is used to simulate the effect of explosive charge density and reaction rate on the results of the Trauzl test. The increase in the volume of the lead block cavity was found to correlate best with the product of the detonation heat and the root of the volume of detonation products. Hydrocode simulation showed that the density of explosive charge and the rate of explosive decomposition affect the dynamics of the interaction of the detonation product and the lead block, and consequently the lead block cavity volume increase. [ABSTRACT FROM AUTHOR]

In this paper, we develop quantum dynamical methods capable of treating the dynamics of chemically reacting systems in an optical cavity in the vibrationally strong-coupling (VSC) limit at finite temperatures and in the presence of a dissipative solvent in both the few and many molecule limits. In the context of two simple models, we demonstrate how reactivity in the collective VSC regime does not exhibit altered rate behavior in equilibrium but may exhibit resonant cavity modification of reactivity when the system is explicitly out of equilibrium. Our results suggest experimental protocols that may be used to modify reactivity in the collective regime and point to features not included in the models studied, which demand further scrutiny. [ABSTRACT FROM AUTHOR]

Thermochemical conversions are pathways for biomass utilization to produce various value-added energy and chemical products. For the development of novel thermochemical conversion technologies, an accurate understanding of the reaction performance and kinetics is essential. Given the diversity of the thermal analysis techniques, it is necessary to understand the features and limitations of the reactors, ensuring that the selected thermal analysis reactor meets the specific need for reaction characterization. This paper provides a critical overview of the thermal analysis reactors based on the following perspectives: 1) gas flow conditions in the reactor, 2) particle's external and internal heat and mass transfer limitations, 3) heating rate, 4) temperature distribution, 5) nascent char production and reaction, 6) liquid feeding and atomization, 7) simultaneous sampling and analyzing of bed materials, and 8) reacting atmosphere change. Finally, prospects and future research directions in the development of analysis techniques are proposed. [ABSTRACT FROM AUTHOR]

The commercialization of Li−S batteries is seriously hindered by polysulfides with severe shuttle effect, and the inherent insulating properties and slow reaction kinetics of insoluble Li2S products. Transition metal sulfides (TMSs) have a high adsorption capacity for polysulfides and have been shown to have a strong catalytic effect on polysulfide conversion reactions. This paper reviews the research on the application of Unary TMSs, heterostructures, etc. in Li−S batteries, and gives some research methods for TMD catalysts in Li−S batteries. Finally, it points out the main focuses and direction of future Li−S battery research and development. It aims to provide some insights into the design and manufacture of advanced Li−S batteries for commercial use. [ABSTRACT FROM AUTHOR]

In this paper, we consider the problem of placing a minimal number of controls to achieve controllability for a class of networked control systems that are based on the original Turing reaction-diffusion model, which is governed by a set of ordinary differential equations with interactions defined by a ring graph. Turing model considers two morphogens reacting and diffusing over the spatial domain and has been widely accepted as one of the most fundamental models to explain pattern formation in a developing embryo. It is of great importance to understand the mechanism behind the various reaction kinetics that generate such a wide range of patterns. As a first step towards this goal, in this paper we study controllability of Turing model for the case of cells connected as a square grid in which controls can be applied to the boundary cells. We first investigate the minimal control placement problem for the diffusion only system. The eigenvalues of the diffusion matrix are classified by their geometric multiplicity, and the properties of the corresponding eigenspaces are studied. The symmetric control sets are designed to categorize control candidates by symmetry of the network topology. Then the necessary and sufficient condition is provided for placing the minimal control to guarantee controllability for the diffusion system. Furthermore, we show that the necessary condition can be extended to Turing model by a natural expansion of the symmetric control sets. Under certain circumstances, we prove that it is also sufficient to ensure controllability of Turing model. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to extract electrochemical reaction kinetics parameters, such as Tafel slope, exchange current density and equilibrium potential, which cannot be directly measured, this study aims to propose an improved particle swarm optimization (PSO) algorithm. Design/methodology/approach: In traditional PSO algorithms, each particle's historical optimal solution is compared with the global optimal solution in each iteration step, and the optimal solution is replaced with a certain probability to achieve the goal of jumping out of the local optimum. However, this will to some extent undermine the (true) optimal solution. In view of this, this study has improved the traditional algorithm: at each iteration of each particle, the historical optimal solution is not compared with the global optimal solution. Instead, after all particles have iterated, the optimal solution is selected and compared with the global optimal solution and then the optimal solution is replaced with a certain probability. This to some extent protects the global optimal solution. Findings: The polarization curve plotted by this equation is in good agreement with the experimental values, which demonstrates the reliability of this algorithm and provides a new method for measuring electrochemical parameters. Originality/value: This study has improved the traditional method, which has high accuracy and can provide great support for corrosion research. [ABSTRACT FROM AUTHOR]

The FitzHugh–Nagumo model has been used empirically to model certain types of neuronal activities. It is also a non-linear dynamical system applicable to chemical kinetics, population dynamics, epidemiology and pattern formation. In the literature, many approaches have been proposed to study its dynamics. In this paper, initially, we have employed cutting-edge tools from discrete dynamics for discretization and fixed points. It has been proven that an exact discrete scheme exists for this paradigm. This project also considers the phase space and integral surfaces of these evolutionary equations. In addition, it carries out a thorough symmetry analysis of this reaction diffusion system to find equivalent systems. Moreover, steady-state solutions are obtained using ansatzes for traveling wave solutions. The existence of infinite traveling wave solutions has also been proven. Yet again, this investigation establishes the potential of symmetry methods to unravel non-linearity. Finally, singular perturbation theory has been employed to obtain analytical approximations and to study stability in different parameter regimes. [ABSTRACT FROM AUTHOR]

Due to the availability of fuel, favorable kinetics, and high output energy, the deuterium-tritium (D-T) fusion reaction is dominantly used in thermonuclear fusion. This paper presents a detailed, step-by-step theoretical calculation of the D-T fusion cross-section within the framework of the phenomenological R-matrix method. The fundamental principles of the phenomenological R-matrix method are outlined. Nuclear and Coulomb interactions are addressed by the R-matrix formalism, which classifies the configuration space into internal and external regions, respectively. Precise Coulomb functions are utilized in the calculations, essential for the accurate determination of the penetration and shift factors. Precise Coulomb functions for the D+T, 4He+12C systems have been calculated. The penetration and shift factors for the D+T system for a given angular momentum have been obtained. Two different R-matrix models with parameters from recent scientific papers are employed to calculate D-T fusion cross-sections and reaction rates, which are then compared with those obtained from the ENDF/B-VIII.0 library data. Within a crucial low-energy range (from 0 to 0.1 MeV), important for fusion technology, our results show quite good agreement with experimental data, while in a high-energy range, the obtained results are slightly underestimated due to non-resonant 5He levels not being taken into account. These findings indicate that the models can be used for future thermonuclear fusion applications. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive investigation into the design of a methane oxidation catalyst aftertreatment system specifically tailored for the Wärtsilä W31DF natural gas engine which has been converted to a reactivity-controlled compression ignition NG/Diesel engine. A GT-Power model was coupled with a predictive physical base chemical kinetic multizone model (MZM) as a combustion object. In this MZM simulation, a set of 54 species and 269 reactions as chemical kinetic mechanism were used for modelling combustion and emissions. Aftertreatment simulations were conducted using a 1D air-path model in the same GT-Power model, integrated with a chemical kinetic model featuring 15 catalytic reactions, based on activation energy and species concentrations from combustion outputs. The latter offered detailed exhaust composition and exhaust thermodynamic data under specific operating conditions, effectively capturing the intricate interactions between the investigated aftertreatment system, combustion, and exhaust composition. Special emphasis was placed on the formation of intermediate hydrocarbons such as C2H4 and C2H6, despite their concentrations being lower than that of CH4. The analysis of catalytic conversion focused on key species, including H2O, CO2, CO, CH4, C2H4, and C2H6, examining their interactions. After consideration of thermal management and pressure drop, a practical choice of a 400 mm long catalyst with a density of 10 cells per cm2 was selected. Investigations of this catalyst's specification revealed complete CO conversion and a minimum of 89% hydrocarbon conversion efficiency. Integrating the exhaust aftertreatment system into the air path resulted in a reduction in engine-indicated efficiency by up to 2.65% but did not affect in-cylinder combustion. [ABSTRACT FROM AUTHOR]

The paper considers the problem of choosing the composition, structure, and size of spherical catalyst nanoparticles for carrying out plasmon-induced polymerization reactions. The concept of reducing the activation energy of the reaction in the presence of a catalyst and, accordingly, increasing the rate of a chemical reaction during heating due to the excitation of surface plasmon resonance is presented. Using the Drude model for the dielectric function, relationships were obtained for the frequency dependences of such characteristics as the real and imaginary parts of the polarizability, heating and the rate of chemical reactions when monometallic and bimetallic nanoparticles are used as catalysts, as well as the amplification of fields in their vicinity. The concepts developed in this work take into account the classical size dependence of the effective electron relaxation rate in monometallic and bimetallic nanoparticles under the assumption of diffuse scattering of electrons. Changes in the positions of the maxima of the imaginary part of the polarizability, heating, and reaction rate are analyzed with a change in the radii of monometallic and bimetallic nanoparticles. It is shown that the maxima of the dependences under study correspond to dipole surface plasmon resonances, and their number depends on the particle morphology. Changes in the amplification of electric fields in the vicinity of nanoparticles of different morphology have been studied. It has been found that the enhancement of the fields in all considered cases is maximum on the surface of the nanoparticle and decreases with distance from it. Practical recommendations are formulated regarding the size, composition and structure of nanoparticles for plasmon catalysis, which provide the highest rates of chemical reactions. Thus, all obtained frequency dependences have one maximum for monometallic and two maxima for bimetallic nanoparticles. [ABSTRACT FROM AUTHOR]

A porous material that has been contaminated with a hazardous chemical agent is typically decontaminated by applying a cleanser solution to the surface and allowing the cleanser to react into the porous material, neutralising the agent. The agent and cleanser are often immiscible fluids and so, if the porous material is initially saturated with agent, a reaction front develops with the decontamination reaction occurring at this interface between the fluids. We investigate the effect of different initial agent configurations within the pore space on the decontamination process. Specifically, we compare the decontamination of a material initially saturated by the agent with the situation when, initially, the agent only coats the walls of the pores (referred to as the 'agent-on-walls' case). In previous work (Luckins et al., European Journal of Applied Mathematics, 31(5):782–805, 2020), we derived homogenised models for both of these decontamination scenarios, and in this paper we explore the solutions of these two models. We find that, for an identical initial volume of agent, the decontamination time is generally much faster for the agent-on-walls case compared with the initially saturated case, since the surface area on which the reaction can occur is greater. However for sufficiently deep spills of contaminant, or sufficiently slow reaction rates, decontamination in the agent-on-walls scenario can be slower. We also show that, in the limit of a dilute cleanser with a deep initial agent spill, the agent-on-walls model exhibits behaviour akin to a Stefan problem of the same form as that arising in the initially saturated model. The decontamination time is shown to decrease with both the applied cleanser concentration and the rate of the chemical reaction. However, increasing the cleanser concentration is also shown to result in lower decontamination efficiency, with an increase in the amount of cleanser chemical that is wasted. [ABSTRACT FROM AUTHOR]

The aim of this article is to experimentally determine the role of the environment, consisting of a base oil (PAO), carbon nanomaterials, and optional other additives, as well as the kind of metal in contact with the lubrication film, in the stimulation of zinc dialkyldithiophosphate (ZDDP) additives' effectiveness during protective film formation. This paper focuses on the role of carbon nanostructures in energy transportation and conversion during tribological processes. An antistatic additive (ASA) (not used in lubricating oils) for jet fuels was added to disturb the process of energy conduction (electric charges) through the lubricant film and thus determine how this disturbance affects the kinetics of the ZDDP triboreaction and, consequently, the linear wear. To achieve this research goal, two types of tribological testing devices were used: an Anton Paar tribometer (TRB) and a triboelectric tribometer (TET). The novelty of the present research is in the use of the method for disturbing the flow of charge/energy through the lubricant film with an antistatic additive for jet fuels, ASA, to influence the impact of this energy on the antiwear properties of ZDDP. The following conclusions were drawn: (1) carbon-based nanostructures, i.e., CNTs, AuCNTs, graphene, and fullerenes, are able to change the rate of chemical reactions of ZDDP during tribological processes; (2) CNTs have the ability to catalyze tribochemical reactions of ZDDP, while graphene and fullerenes are not able to perform this effectively; (3) AuCNT takes the role of an inhibitor during ZDDP's triboreaction; and (4) by discharging electric charge/energy, ASA, in cooperation with CNT and AuCNT significantly reduces the rate of the ZDDP reaction. [ABSTRACT FROM AUTHOR]

The lower total temperature and pressure in a dual-mode scramjet engine lead to slower rates of evaporation and chemical reactions, while the inflow velocity is higher than that in a ramjet engine. Consequently, enhancing fuel residence time becomes a more critical challenge. The cavity is a crucial device for enhancing the residence time. However, the quantitative residence capacity and the mechanism have not yet been revealed, especially in wide-range speed inflow conditions. This work employs the delayed detached eddy simulation method to investigate the mass transport and fluid residence characteristics of the wide-range subsonic flow (Ma = 0.3, 0.4, 0.5, 0.6, 0.7) over the cavity. The Lagrangian coherent structure is utilized to characterize the dynamic evolution of the large-scale vortex in the cavity shear layer. Particle tracking is employed to delicately determine the net mass exchange rate and the quantitative cavity residence time. Based on the entrainment process of the large-scale vortex and mass exchange between the mainstream and cavity, this paper proposes a novel theoretical entrainment-impinging model of the large-scale vortex for calculating the residence enhancement coefficient ( τ r ). The theoretical model demonstrates that the residence enhancement coefficient is a function of the cavity geometry (L, D), the vortex radius ( r v ), the shedding Strouhal number of the vortex (St), and the vortex/trailing edge interaction coefficient (η). Furthermore, it has been proven that the model proposed in this paper is applicable to a wide range of inflow turbulent conditions and cavity geometric configurations. [ABSTRACT FROM AUTHOR]

Understanding the world around us is a growing necessity for the whole public, as citizens are required to make informed decisions in their everyday lives about complex issues. Systems thinking (ST) is a promising approach for developing solutions to various problems that society faces and has been acknowledged as a crosscutting concept that should be integrated across educational science disciplines. However, studies show that engaging students in ST is challenging, especially concerning aspects like change over time and feedback. Using computational system models and a system dynamics approach can support students in overcoming these challenges when making sense of complex phenomena. In this paper, we describe an empirical study that examines how 10th grade students engage in aspects of ST through computational system modeling as part of a Next Generation Science Standards-aligned project-based learning unit on chemical kinetics. We show students' increased capacity to explain the underlying mechanism of the phenomenon in terms of change over time that goes beyond linear causal relationships. However, student models and their accompanying explanations were limited in scope as students did not address feedback mechanisms as part of their modeling and explanations. In addition, we describe specific challenges students encountered when evaluating and revising models. In particular, we show epistemological barriers to fruitful use of real-world data for model revision. Our findings provide insights into the opportunities of a system dynamics approach and the challenges that remain in supporting students to make sense of complex phenomena and nonlinear mechanisms. [ABSTRACT FROM AUTHOR]

The complexity of structural changes in LiMnyFe1−yPO4 (LMFP) during delithiation/lithiation poses unique challenges in kinetics and cycling, distinguishing it significantly from LiFePO4. Therefore, comprehending the delithiation/lithiation mechanism of LMFP is essential to optimize material design, synthesis, and battery application management. However, existing reports show apparent discrepancies and contradictions. This paper elucidates the relaxation property of LMFP, providing a comprehensive review of crystal structure and electronic structure change mechanisms during delithiation/lithiation based on in situ characterization. Regarding crystal structure transition, variations in LMFP's compositional uniformity across different literature, stemming from differences in the synthesis process, may contribute to multiple mechanisms. Concerning electronic structure changes, the chemical environments between Fe and Mn are mutual interaction, and the sluggish kinetics of the Mn2+/Mn3+ reaction suggest partial charge compensation by oxygen in the phosphate group. Building on these findings, the paper addresses existing research deficiencies and identifies potential directions for future investigations into the delithiation/lithiation mechanism of LMFP, aiming to provide a solid theoretical foundation for developing new olivine‐type cathode materials with superior electrochemical performance. [ABSTRACT FROM AUTHOR]

(1) Background: A new probabilistic physico-chemical model of the drifting key parameter of measuring equipment is proposed. The model allows for the integrated consideration of degradation processes (electrolytic corrosion, oxidation, plastic accumulation of dislocations, etc.) in nodes and elements of measuring equipment. The novelty of this article lies in the analytical solutions that are a combination of the Fokker–Planck–Kolmogorov equation and the equation of chemical kinetics. The novelty also consists of the simultaneous simulation and analysis of probabilistic, physical and chemical processes in one model. (2) Research literature review: Research works related to the topic of the study were analyzed. The need for a probabilistic formulation of the problem is argued, since classical statistical methods are not applicable due to the lack of statistical data. (3) Statement of the research problem: A probabilistic formulation of the problem is given taking into account the physical and chemical laws of aging and degradation. (4) Methods: The author uses methods of probability theory and mathematical statistics, methods for solving the stochastic differential equations, the methods of mathematical modeling, the methods of chemical kinetics and the methods for solving a partial differential equations. (5) Results: A mathematical model of a drifting key parameter of measuring equipment is developed. The conditional transition density of the probability distribution of the key parameter of measuring equipment is constructed using a solution to the Fokker–Planck–Kolmogorov equation. The results of the study on the developed model and the results of solving the applied problem of constructing the function of the failure rate of measuring equipment are presented. (6) Discussion: The results of comparison between the model developed in this paper and the known two-parameter models of diffusion monotonic distribution and diffusion non-monotonic distribution are discussed. The results of comparison between the model and the three-parameter diffusion probabilistic physical model developed by the author earlier are also discussed. (7) Conclusions: The developed model facilitates the construction and analysis of a wide range of metrological characteristics such as measurement errors and measurement ranges and acquisition of their statistical estimates. The developed model is used to forecast and simulate the reliability of measuring equipment in general, as well as soldered joints of integrated circuits in special equipment and machinery, which is also operated in harsh conditions and corrosive environments. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to study the color change kinetics of lac dye in response to pH and food spoilage metabolites (ammonia, lactic acid and tyramine) for its potential application in intelligent food packaging. Design/methodology/approach: UV-Vis spectroscopy was used to study the color change of dye solution. Ratio of absorbance of dye solution at 528 nm (peak of ionized form) to absorbance at 488 nm (peak of unionized form) was used to study the color change. Color change kinetics was studied in terms of change in absorbance ratio (A528/A488) with time using zero- and first-order reaction kinetics. An indicator was prepared by incorporating lac dye in agarose membrane to validate the result of study for monitoring quality of raw milk. Findings: Dye was orange-red in acidic medium (pH: 2 to 5) and exhibited absorbance peak at 488 nm. It turned purple in alkaline medium (pH: 7 to10) and exhibited absorbance peak at 528 nm. The change in absorbance ratio with pH followed zero-order model. Acid dissociation constant (pKa) of dye was found to be 6.3. Color change of dye in response to ammonia and tyramine followed zero-order reaction kinetics, whereas for lactic acid, the first-order model was found best. In the validation part, the color of the indicator label changed from purple to orange-red when the milk gets spoiled. Originality/value: The study opens a new application area for lac dye. The results suggest that lac dye has potential to be used as an indicator in intelligent food packaging for detection of spoilage in seafood, meat, poultry and milk. [ABSTRACT FROM AUTHOR]

Aqueous zinc-ion batteries (ZIBs) have attracted enormous attention for future energy-storage devices owing to their high theoretical capacity and environmental friendliness. However, obtaining cathodes with a high specific capacity and fast reaction kinetics remains a huge challenge. Herein, Cu-VOx material with a thin sheet microsphere structure composed of nanoparticles was prepared by a simple hydrothermal reaction, which improved reaction kinetics and specific capacity. Pre-embedding Cu2+ into V2O5 to introduce abundant oxygen vacancies extended the interlayer distance to 1.16 nm, weakened the effect of the V-O bonds, and improved the electrical conductivity and structural stability. At the same time, the influence of different valence metal ions (M = K+, Cu2+, Fe3+, Sn4+, Nb5+, and W6+) pre-embedded in V2O5 was studied. Benefiting from a large interlayer spacing, high electrical conductivity, and excellent structural stability, the Cu-VOx electrode demonstrated a high specific capacity of 455.9 mAhg-1 at 0.1 A g-1. Importantly, when the current density was increased to 6 A g-1,the Cu-VOx electrode still achieved a high specific capacity of 178.8 mA h g-1 and maintained a high capacity retention of 76.5% over 2000 cycles. [ABSTRACT FROM AUTHOR]

Adding dopants to the structure and coupling cocatalysts on the surface are traditional strategies to inhibit carrier recombination and high catalytic barriers for enhancing the performance of water splitting of the BiVO4 photoanode. An inexpensive post-treatment method was developed herein via modifying the BiVO4 (BVO) photoanode with KBr solution. Unlike the traditional strategies, this approach effectively overcomes carrier recombination on the BVO photoanode surface. The Br–BiVO4 (Br–BVO) photoanode was optimized and exhibited a remarkable cathodic shift (350 mV) of the onset potential, as well as an excellent photocurrent density, which was increased to 256% of the pure BVO photoanode. The Faraday efficiencies of oxygen evolution and hydrogen evolution (FEO2, FEH2) were 98.4% and 96.7%, respectively. The photoelectrochemical (PEC) characterization revealed that the adsorption of Br− on the BVO photoanode induced surface polarization and can rapidly trap holes and prolong carriers' lifetimes, facilitating the participation of most holes in the oxygen evolution reaction (OER). Adsorption of Br− also decreased the overpotential of the OER on the BVO photoanode, consequently enhancing reaction kinetics. This study presents a straightforward and feasible approach to enhance the PEC performance of the BiVO4-based photoanode. [ABSTRACT FROM AUTHOR]

CoTe2 as a high-performance anode material for potassium ion batteries still faces a lot of challenges that hinder its electrochemical performance, including poor intrinsic electronic conductivity, slow reaction kinetics, and significant volume changes during charging and discharging processes. To address these issues, one-dimensional CoTe2 nanorods were synthesized using a one-step hydrothermal method and then coated with a carbon layer to form CoTe2@C nanocomposites. The resulting composite exhibited a significant interaction between CoTe2 and the carbon layer, resulting in the formation of a stable heterostructure. This interaction not only improved the electrical conductivity of the composites but also facilitated the migration of electrons and K+ ions. When used as the anode for potassium ion batteries, the CoTe2@C anode demonstrated enhanced electrochemical performance. At a current density of 0.5 A g−1, the CoTe2@C anode exhibited a reversible capacity of 100.3 mA h g−1 after 1000 cycles. Even at a higher current density of 1.0 A g−1, it maintained a high reversible capacity of 72.5 mA h g−1 after 3000 cycles. Furthermore, it displayed excellent rate capability, with an average reversible capacity of 98.0 mA h g−1 at a high rate of 5.0 A g−1, showing a potential application capability for potassium ion batteries. [ABSTRACT FROM AUTHOR]

Reforming ammonia to hydrogen using engine exhaust waste heat is a promising technology to improve the combustion performance and reduce the exhaust emissions of ammonia-fueled engines. However, there are still a research gap between the laboratory-level catalytic reforming tests and the practical application in engine systems. In particular, there are urgent needs to further understanding the ammonia reforming characteristics and developing the simulaiton models for the engine system optimization. In this paper, we conducted the experiments of catalytic reforming NH 3 to H 2 to study the effects of the reaction temperature, gas hour space velocity (GHSV) and pressure on the thermo-catalytic decomposition characteristicsxin. The results indicate that both the ammonia catalytic conversion and reforming efficiency exhibit an increasing trend with the rise in reaction temperature, while these two parameters demonstrate a decreasing trend with the increase in GHSV and pressure. The rate of hydrogen production is directly proportional to temperature, GHSV, and reaction pressure. Conversely, the energy required per unit of hydrogen production decreases with temperature but increases with GHSV and reaction pressure. The energy flow analysis shows that increasing the reforming temperature increases the reforming losses, but the total calorific value of the reformate increases, which is expected to improve the overall efficiency of ammonia fueled engines and reduce the unburned ammonia emissions. Simulation results show that, the improved Temkin-Pyzhev global rate model can significantly improve the accuracy of the ammonia catalytic decomposition process prediction. [Display omitted] • A novel energy flow analysis method for thermo-catalytic reforming is presented. • A precise predictive model for thermo-catalytic characteristics is established. • The thermo-catalytic system has a system efficiency of up to 94%. • The thermo-catalytic system has a reforming efficiency of up to 112%. [ABSTRACT FROM AUTHOR]

Symmetrical solid oxide cells (SSOCs) are very useful for energy generation and conversion. To fabricate the electrode of SSOC, it is very time‐consuming to use the conventional approach. In this work, we design and develop a novel method, extreme heat treatment (EHT), to rapidly fabricate electrodes for SSOC. We show that by using the EHT method, the electrode can be fabricated in seconds (the fastest method to date), benefiting from enhanced reaction kinetics. The EHT‐fabricated electrode presents a porous structure and good adhesion with the electrolyte. In contrast, tens of hours are needed to prepare the electrode by the conventional approach, and the prepared electrode exhibits a dense structure with a larger particle size due to the lengthy treatment. The EHT‐fabricated electrode shows desirable electrochemical performance. Moreover, we show that the electrocatalytic activity of the perovskite electrode can be tuned by the vigorous approach of fast exsolution, deriving from the increased active sites for enhancing the electrochemical reactions. At 900 °C, a promising peak power density of 966 mW cm−2 is reached. Our work exploits a new territory to fabricate and develop advanced electrodes for SSOCs in a rapid and high‐throughput manner. [ABSTRACT FROM AUTHOR]

Due to the higher conductivity of selenium than sulfur, lithium selenium (Li–Se) batteries have received increasing attention. However, the shuttle effect and the slow conversion kinetics of polyselenides have resulted in poor cycling performance of Li–Se batteries. In this work, a CoTe2 and MOF derived composite (CoTe2-MD) was designed and synthesized. As a dual-functional matrix, the MOF derivative acted as an adsorbent and effectively reduced the dissolution of the polyselenides in ether electrolytes via physical/chemical absorption. CoTe2 acted as an electrocatalyst, which accelerated the conversion reaction of the polyselenides and improved the redox kinetics of the reactions. The results proved that the dual-functional matrix consisting of the adsorbent and electrocatalyst further suppressed the shuttle effect and significantly improved the cycle stability of the Li–Se batteries. At 0.5C, the Se/CoTe2-MD electrode showed 540.4 mA h g−1 of initial discharge capacity. Even after 200 cycles, it still maintained a reversible capacity of 454.1 mA h g−1, with a decay rate of only 0.08% per cycle. [ABSTRACT FROM AUTHOR]

Among numerous semiconductors, BiVO4 has a suitable bandgap width, excellent valence band energy level and high activity for visible light water oxidation. It is an important oxygen evolution photocatalyst, but its carrier migration rate is still lower than other semiconductor materials. Therefore, in this paper, transition metal cations such as Fe3+ were selectively exchanged with V5+ in BiVO4 in a high-temperature Ar atmosphere by vapor phase cation exchange method, cationic bonds with strong binding force were formed at the interface between metal elements and catalysts, effectively accelerating bulk to surface charge separation. The adsorption energy and surface oxidation kinetics of the intermediate in the process of water oxidation were enhanced, and the photoelectrochemical properties of the intermediate were effectively improved. The vapor phase cation exchange between Fe3+ and V5+ of BiVO4 photoanode makes the metal element and the catalyst form a strong cationic bond at the interface, which greatly reduces the charge transport resistance to a certain extent, accelerates the water reaction kinetics, which can not only significantly improve the stability, but also increase the photocurrent density and significantly reduce the starting potential. [ABSTRACT FROM AUTHOR]

In the field of research on renewable energy conversion and storage methods, the development of catalysts with excellent properties and outstanding stability for oxygen evolution reaction (OER) acting at various pH values has become a much-anticipated research focus. RuO 2 as a benchmark OER catalyst, its wide application has always been limited by slow reaction kinetics and limited persistence. In this paper, Mn-doped RuO 2 material was developed and the optimum doping ratio was identified for using as an OER electrocatalyst under general purpose pH media. Mn 0.1 Ru 0.9 O 2 exhibited a lower overpotential value of 224 mV in acidic environment with a Tafel slope value of 51.62 mV dec−1. Moreover, in alkaline and neutral environments, overpotentials of 231 mV and 376 mV were required to obtain a current density of 10 mA cm−2, respectively. In addition, through continuous stability testing over 24 h in alkaline, acidic and neutral solutions, it has been further demonstrated that the Mn-doped RuO 2 material exhibits extremely high stability. The advancements in this research offer crucial insight into the rational development of efficient and durable RuO 2 -based catalysts. [Display omitted] • Mn 0.1 Ru 0.9 O 2 is successfully synthesized by a facile sol-gel method. • Mn doping modulates the electronic structure of RuO 2. • The catalyst exhibits enhanced OER activity and stability in pH-Universal media. [ABSTRACT FROM AUTHOR]

[Display omitted] In this paper, we have developed a simple and efficient sulfur-amine chemistry strategy to prepare a three-dimensional (3D) porous Ti 3 C 2 T x composite with large amounts of N and S terminal groups. The well-designed 3D macroporous architecture presents enlarged interlayer spacing, large specific surface area, and unique porous structure, which successfully solves the re-stacking issue of MXene during storage and electrode fabrication. It is the amount of concentrated hydrochloric acid added to the S-EDA (ethylenediamine)/MXene colloidal suspension that is critical to the formation of 3D morphology. In addition, N and S terminals on MXene could improve the adsorption ability of K+. Owing to the synergistic effect of the structure design and terminal modification, the N, S codoped three-dimensional porous Ti 3 C 2 T x (3D-NSPM) material shows a high surface capacitive contribution and rapid diffusion kinetics for K+ and Na+. As a result, the as-prepared 3D-NSPM delivers high reversible capacity (237 and 273 mAh g−1 at 0.1 A g−1 for PIBs and SIBs, respectively), superb cycling stability (84.9% capacity retention after 10,000 cycles at 1 A g−1 in PIBs and 74.0% capacity retention after 2200 cycles at 1 A g−1 in SIBs), and excellent rate capability (111 and 196 mAh g−1 at 5 A g−1 for PIBs and SIBs, respectively), which are superior to other MXene-based anodes for PIBs and SIBs. Moreover, the described strategy provides a new insight for constructing the 3D porous structure from 2D building blocks beyond MXene. [ABSTRACT FROM AUTHOR]

Morphology control is widely acknowledged as an effective method for optimizing the exposed facets and active sites of palladium (Pd) nanocrystals, which enhances their electrocatalytic activity. However, conventional approaches inevitably alter the reaction from both thermodynamic and kinetic perspectives, rendering control intricate. In this investigation, we introduce a specialized strategy to achieve morphology control over PdAuAg nanocrystals, demonstrating their exceptional performance as electrocatalysts for the ethanol oxidation reaction (EOR). Specifically, three metallic precursor solutions were individually introduced into a one-pot reaction system at controlled rates using syringe pumps, allowing for separate manipulation of each metal atom's concentration without cross-reaction. Consequently, a variety of products with unique morphologies and structures were produced, all adhering to the same protocol except for the rate of metal atom introduction. When catalyzing the EOR, the optimized PdAuAg nanocrystals supported on carbon black exhibited a sevenfold increase in mass activity compared to Pt/C, as well as enhanced reaction kinetics and long-term stability. Density functional theory (DFT) calculations confirmed that crystal facets can influence the ethanol oxidation reaction pathway, rationalizing the improved catalytic performance. Our study presents a viable approach for modulating the morphology of trimetallic nanocrystals by varying the feed rate of metal atoms in a one-pot reduction, illuminating the rational design of high-performance fuel cell catalysts. [ABSTRACT FROM AUTHOR]

The reaction order plays a crucial role in evaluating the response rate of acid-rock. However, the conventional two-scale model typically assumes that the reaction order is constant as one, which can lead to significant deviations from reality. To address this issue, this study proposes a novel multi-order dynamic model for acid-rock reaction by combining rotating disk experimental data with theoretical derivation. Through numerical simulations, this model allows for the investigation of the impact of acidification conditions on different orders of reaction, thereby providing valuable insights for on-site construction. The analysis reveals that higher response orders require higher optimal acid liquid flow rates, and lower optimal Hþ diffusion coefficients, and demonstrate no significant correlation with acid concentration. Consequently, it is recommended to increase the displacement and use high-viscosity acid for reservoirs with high calcite content, while reducing the displacement and using low-viscosity acid for reservoirs with high dolomite content. [ABSTRACT FROM AUTHOR]

The application of light-weight current collectors is preferred because of the increased energy density of the batteries. Bearing it in mind, the cathode is designed with self-made paperlike memberane as current collector coupled with another interlayer to enable the high-energy-density lithium-sulfur batteries. Via a facile and green step-by-step methodology, the hybrid membrane is finalized successfully, consisting of reduced graphene oxide sheets covering paper-derived carbon (GPC) bearing Fe@Fe2O3 and Fe1−xS@Fe2O3 core-shell nanoparticles (FeFeO/FeSFeO@GPC). The film works as the current collector and interlayer simultaneously considering the porous and conductive features. As demonstrated by the electrochemical testing, the FeFeO/FeSFeO@GPC hybrid cell exhibits attractive cycling stability and superior rate capability. The cell configuration and structural/composition merits of FeFeO/FeSFeO@GPC film facilitate the faster reaction kinetics, conducive to the improvement of capacity retention. In view of the effective cathode design, the areal sulfur loading is increased to 10.46 mg·cm−2 and a reversible capacity of 6.67 mAh·cm−2 can be retained after 60 cycles at 0.1 C. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) has gained a lot of interest as a potassium storage material with a high anode capacity. However, the slow reaction kinetics and its highly unstable structure prevent the full realization of its electrochemical performance during the insertion and extraction of K+. Herein, sulfur vacancy-modified MoS2 nanolayers grown coaxially with an external carbon coating and internal carbon nanotube support (denoted as C–MoS2−x@CNTs) are designed as anode materials for potassium storage. This unique structure enables fast K+ reaction kinetics facilitated by S vacancy engineering, uniform growth of MoS2 nanolayers controlled by internal carbon nanotubes, and the stability of the complete electrode preserved by the encapsulation of carbon. Therefore, the prepared C–MoS2−x@CNTs reveal a high rate performance value of 180.9 mA h g−1 (5 A g−1) with a reversible capacity value of 323.8 mA h g−1 (50 mA g−1). It sustains a capacity of 141.2 mA h g−1, exhibiting excellent cycling stability, even after 300 cycles at a current density of 2 A g−1. [ABSTRACT FROM AUTHOR]

To date, researchers in chase of economic cost-efficiency are faced with the problem of developing effective catalysts for water splitting without the use of platinoids. Herein, catalytic properties of hexanuclear rhenium cluster complexes are investigated in application to the hydrogen evolution reaction (HER). A paste composite electrode containing the cluster complexes was obtained, producing a current density of 10 mA cm−2 at an extraordinarily low overpotential of 90 mV (RHE). The {Re6Se8}-based complexes have shown very favorable reaction kinetics via 102 mV dec−1 value of the Tafel slope for HER reaction within the composition of the paste electrode. Model calculations of kinetic parameters using density functional theory also support the experimental findings. This work underscores the perspectivity of rhenium cluster compounds in HER and opens a promising avenue toward the practical implementation of hydrogen production through electrochemical water splitting. [ABSTRACT FROM AUTHOR]

In this paper, we consider model problems of chemical kinetics that lead to singularly perturbed parabolic equations in domains with nonsmooth boundaries. The solvability of such problems depends on the properties of the inhomogeneity at corner points of the boundary. [ABSTRACT FROM AUTHOR]