Reactive Layer Research Articles

Understanding Steel Corrosion: Surface Chemistry and Defects Explored Through DFT Modelling—A Review

Corrosion poses a critical challenge to the durability and performance of metals and alloys, particularly steel, with significant economic, environmental, and safety implications. The corrosion susceptibility of steel is influenced by aggressive chemical species, intrinsic material defects, and environmental factors. Understanding the atomic-scale mechanisms governing corrosion is essential for developing advanced corrosion-resistant materials. Density functional theory (DFT) has become a powerful computational tool for investigating these mechanisms, providing insight into the adsorption, diffusion, and reaction of corrosive species on iron surfaces, the formation and stability of metal oxides, and the influence of defects such as vacancies and grain boundaries in localised corrosion. This review presents a comprehensive analysis of recent DFT-based studies on iron and steel surfaces, emphasising the role of solvation effects and van der Waals corrections in improving model accuracy. It also explores defect-driven corrosion mechanisms and the formation of protective and reactive oxide layers under varying oxygen coverages. By establishing accurate DFT modelling approaches, this review provides up-to-date literature insights that support future integration with machine learning and multiscale modelling techniques, enabling reliable atomic-scale predictions.

Sulfidated zero-valent iron bimetals for passive remediation of chlorinated vapors in the subsurface.

Sulfidated zero-valent iron bimetals for passive remediation of chlorinated vapors in the subsurface.

The flexural response of hybrid beams strengthened with fiber polymer rebars

Abstract The current study aimed to examine the value of applying the hybridization approach to study the flexural behavior of hybrid reinforced concrete beams including two different concrete types: normal strength concrete and reactive powder concrete. In addition, carbon fiber-reinforced polymer bars and glass fiber-reinforced polymer bars were bonded in the tension face of the hybrid RC beams utilizing the near-surface-mounted technique. Eight simply supported reinforced concrete beams were tested. The hybridization technique enhanced the flexural behavior and increased the first crack and ultimate loads. Furthermore, the hybrid beams are stiffer than that of a normal beam, and it became even stiffer as the reactive powder concrete layer thickness increased. The hybrid beams that were strengthened with carbon fiber-reinforced polymer bars displayed higher load capacity by about 20% more than those strengthened with glass fiber-reinforced polymer bars.

Mantis shrimp-inspired functionalized plant fibers to fabricate a soy protein adhesive with high strength and mildew resistance.

Mantis shrimp-inspired functionalized plant fibers to fabricate a soy protein adhesive with high strength and mildew resistance.

A novel Ti/TiAl laminated composite with excellent shear properties

In this study, Ti/TiAl laminated composites consisting of Ti layer, α2-Ti3Al interfacial reactive layer, and TiAl layer were successfully prepared by spark plasma sintering using alternately stacking Ti and TiAl powders. The corresponding microstructural evolution and shear strength of the laminated composites were systematically studied. Laminated composites with different intermediate layers (Ti layer, TiAl layer, and Ti3Al layer) showed different shear fracture behaviors, and the ultimate shear strength of Ti layer, TiAl layer, and Ti3Al layer reached about 622 MPa, 466 MPa, and 328 MPa, respectively, indicating excellent shear performance. Different interlayer shear tests showed different crack extension behaviors, the main cracks in Ti3Al intermediate layer propagated along stress direction and penetrated into Ti3Al layers. The crack growth in TiAl intermediate layers revealed that the main cracks initiated from TiAl layer and extended to the Ti3Al layer with weak shear strength. When the ductile Ti layer was sheared, the Ti intermediate layer can release the applied shear stress by the plastic deformation and the residual shear force transferred to the Ti3Al layer forming microcracks. The excellent shear properties of novel Ti/TiAl laminated composite was attributed to the in-situ reaction transition interface.

Layered detonation propagation subject to bilateral expansion: Role of the air layer height

A two-dimensional numerical study was conducted to reveal the role of air layer height on cellular detonations propagating through a layer of vaporized kerosene/air reactant bounded by inert gas (upper side) and air (lower side). A series of cases with different reactive layer heights (h) and air layer heights (h2) are simulated and analyzed. The results indicate that the detonation propagation structures and ignition regimes at the interface between the reactive and air layers are significantly affected by h2. At h2 = 5.8λCJ (λCJ is theoretical cell width), the bottom oblique shock wave propagated as regular reflection structures, and the ignition regime relied on transverse detonations. As the h2 decreases below 2.9λCJ, the bottom oblique shock forms a Mach reflection structure with the bottom wall, and the detonation front ignition regimes can be divided into three types based on h2. The first ignition regime is also through transverse detonation (at h2 = 2.9λCJ). The second ignition regime is the collision between the reflected triple point, the downward triple point, and the Mach stem (at h2 = 0.72λCJ). However, at h2 = 1.45λCJ, in addition to the above two regimes, the ignition regime also relies on the collision between the downward transverse detonation and the Mach stem. Moreover, it was found that when the h/λ is larger than 5.6, layered detonation affected by bilateral expansion can propagate successfully, which is significantly closer to the rotating detonation experimental values compared with detonations subject to unilateral expansion.

Enhancing the efficiency of direct conversion of ultra-low concentration CO2 in the atmosphere to CH4: Structural modulation of the photocatalytic Janus membrane's reactive layer through integration of membrane formation mechanisms based on thermodynamics and kinetics

Enhancing the efficiency of direct conversion of ultra-low concentration CO2 in the atmosphere to CH4: Structural modulation of the photocatalytic Janus membrane's reactive layer through integration of membrane formation mechanisms based on thermodynamics and kinetics

Effective interface laws for fluid flow and solute transport through thin reactive porous layers

Effective interface laws for fluid flow and solute transport through thin reactive porous layers

Linear quadrature method of moments for solving the transported probability density function model for turbulent combustion

Large eddy simulation (LES) coupled with the transported probability density function (PDF) model has become a promising strategy for modelling turbulent combustion. For solving the high-dimensional PDF transport equation numerically, deterministic quadrature-based moment methods have arisen as an alternative choice besides stochastic particle and stochastic field methods. In this work, we propose a new quadrature-based moment method called linear Quadrature Method Of Moments (LQMOM) for the univariate PDF case. This method assumes that the underlying PDF distribution is smooth and it uses a set of predefined quadrature nodes and weights in the sample space to establish a linear system of equations for the PDF values at the quadrature nodes from the moments. The LQMOM is more efficient than the original QMOM which needs to solve a nonlinear system of equations for the moment inversion. However, it may generate negative PDF values for non-smooth PDF distributions. To remedy this flaw, we construct the LQMOM-QMOM hybrid algorithm by using detectors to detect single- and two-peak distributions. Furthermore, we extend the LQMOM to the multivariate PDF case by utilizing the main idea of the conditional QMOM (CQMOM) to obtain the linear CQMOM (LCQMOM), and then reduce it to the simplified version (LCQMOM-S) to gain efficiency. The LQMOM-QMOM hybrid algorithm for univariate PDFs is tested in a typical example and the LCQMOM-S-CQMOM hybrid algorithm for multivariate PDFs is checked in compressible turbulent reactive 2D shear layer flow and 3D air/H 2 jet. It is shown that the hybrid algorithms can reduce 20–35% simulation time and produce similar results compared with the respective QMOM and CQMOM.

Covalent Deposition of Diels–Alder Reaction on Polyester Fiber Surface and Its Enhancement Mechanism on SBS‐Modified Asphalt

ABSTRACTPolyester (PET) fibers offer excellent chemical stability, mechanical strength, and high‐temperature tolerance, making them promising for asphalt applications. However, their smooth, chemically inert surface limits interfacial bonding with asphalt, reducing the overall performance. To address this, a mild covalent deposition method was employed, utilizing a polydopamine and furfuryl amine crosslinking reaction to incorporate furan groups on PET fibers. This enabled the formation of a dense Diels–Alder (D–A) reactive crosslinking layer. Characterization revealed that this layer increased surface roughness, free energy, and active functional groups, improving wetting and interlocking with asphalt. Rheological tests showed enhanced performance in styrene–butadiene–styrene (SBS)‐modified asphalt composites, with a 7.73% increase in G* at 46°C and an 81.94% improvement in adhesion. Molecular dynamics simulations confirmed the enhanced interfacial interactions between DA‐PET fibers and SBS‐modified asphalt, providing insight into the mechanism behind the improvements. This study presents a novel approach for optimizing PET fiber performance in asphalt materials.

Research on the tribological properties of kaolin/MoDDP composite lubricant additives under heavy load and impact conditions

PurposeWith respect to severe working conditions such as heavy load and impact, this paper aims to investigate the friction reduction and anti-wear performance of kaolin and molybdenum dialkyl dithiophosphate (MoDDP) composite lubricant additives to improve the lubrication effect of a single additive.Design/methodology/approachA four-ball friction test was carried out to determine the optimal concentration of kaolin and organic molybdenum additives and the tribological properties of the kaolin/MoDDP composite lubricant additives. A ring block test of composite lubricant additives was designed to investigate its lubrication performance under the severe working conditions of low speed, heavy load and impact.FindingsThe results showed that the optimal addition mass fractions of kaolin and MoDDP were 4.0 and 1.5 Wt.%, respectively, when kaolin and MoDDP were used as single lubricant additives. Compared with the single additive, the 4.0 Wt.% kaolin/1.5 Wt.% MoDDP composite lubricant additive showed excellent friction reduction and anti-wear effects under heavy load and impact conditions. Physicochemical analysis of the wear surface revealed that the lamellar kaolin additive and MoDDP had excellent synergistic effects, and the friction process promoted the generation of lubricant films containing a chemically reactive layer of MoS2, MoO2, FeS2 and Fe2O3 and a physically adsorbent layer containing SiO2 and Al2O3, which play important roles in anti-wear and friction reduction.Originality/valueThe excellent friction reduction and anti-wear effects of lamellar silicate minerals and the excellent antioxidant properties and good synergistic effects of molybdenum were comprehensively used to develop the composite additives with great lubricating properties.

Enzymatic Redox‐Mediated Fabrication of Textiles with Multimode Synergistic Antimicrobial Activity through Embedding Nanosilver in Dynamic Polydisulfide Networks

Abstract The adhesion and proliferation of bacteria on textiles can lead to unacceptable cross‐infection and potential contamination. Herein, an antimicrobial and anti‐adhesive textile is prepared through enzymatic redox‐mediated fabrication of nanosilver‐embedded polydisulfide networks. Specifically, γ‐methacryloyloxypropyltrimethoxysilane is introduced to cotton fibers to build a reactive hydrophobic layer. Subsequently, α‐lipoic acid‐modified tyramine (mTA) is oxidized using horseradish peroxidase and enzymatically grafted onto the vinylated cotton, producing brown polyphenols containing dynamic disulfide bonds. Ultimately, in situ reduction and entrapment of nanosilver are accomplished by the sulfhydryl groups generated from mTA units, forming an antimicrobial network on fiber surfaces. After contact with bacteria for 30 min or fungi for 3 h, the antibacterial rates of the resulting fabric both reach 99.99%. Benefiting from the encouraging photothermal conversion property, bacteria and fungi on fabric surfaces can be killed after 10 min of irradiation at 100 mW cm−2, demonstrating multimode synergistic antibacterial activity. Strikingly, the fabric has impressively durable antimicrobial and bacterial anti‐adhesive properties, maintaining a high bactericidal efficiency after cyclic bacterial contamination tests. Besides, in situ coloring of the fabric is realized while maintaining its inherent wearability, accompanying by satisfactory biocompatibility and hemocompatibility. The presented work provides novel insights into the design and construction of highly efficient antimicrobial textiles.

Tribological Performance of Nano-CeO2/BNH2 Compound Lubricant Additive

To improve lubricant performance and extend the service life of machinery, the friction reduction and anti-wear performance of nano-cerium oxide (nano-CeO2) and nitrogen-containing heterocyclic borate (BNH2) composite additives were studied in this work, with the goal of obtaining better lubrication effects than a single additive. The results showed that the nano-CeO2 modified with Span80 had good dispersion stability in the base oil. The optimal addition mass fractions of single nano-CeO2 and BNH2 were 0.6 wt% and 1.0 wt%, respectively. Compared with the base oil, 0.6 wt% nano-CeO2 reduced the coefficient of friction by 44.9% and the wear spot diameter by 27.8%, while 1.0 wt% BNH2 reduced the coefficient of friction by 49.1% and the wear spot diameter by 32.8%. Compared with the single additions of nano-CeO2 and BNH2, the compound nano-CeO2/BNH2 further improved the friction reduction and anti-wear performance of the lubricating oil. Compared with the base oil, the 0.8 wt% nano-CeO2/1.0 wt% BNH2 composite additive reduced the coefficient of friction by 55.9% and the diameter of the abrasive spot by 48%. Physicochemical analysis of the wear surface revealed that the combination of nano-CeO2 and BNH2 had excellent synergistic effects. The generated lubricant films of nano-CeO2/BNH2 contained a chemical reactive layer of organic nitride (C–N), Fe2O3, FeO, and B2O3 and a physical adsorbent layer of CeO2 that provided great friction reduction and anti-wear effects during friction.

Enhancing Optical and Electrical Performances via Nanocrystalline Si-Based Thin Films for Si Heterojunction Solar Cells.

Silicon heterojunction (SHJ) solar cells, as one of the most promising passivated contact solar cell technologies of the next generation, have the advantages of high conversion efficiency, high open-circuit voltage, low-temperature coefficient, and no potential-induced degradation. For the single-side rear-emitter SHJ solar cells, the n-type carrier selective layer, which serves as the light-incident side, plays a pivotal role in determining the performance of heterojunction devices. Consequently, a superior n-doped layer should exhibit high optical transmittance and minimal optical absorption, along with a substantial effective doping level to guarantee the formation of dark conductivity (σd) and electron-transport capacity. In this work, we investigated the optical and electrical properties of different n-type monolayers and stacked gradient multilayers, including monolayer, bilayer, and trilayer Si-based thin films, acting as electron-transport layers (ETL) prepared by plasma-enhanced chemical vapor deposition, and studied the influences of these above layers on the performance of SHJ solar cells. The experimental results demonstrate that the ETL with an n-nc-Si:H/n-nc-SiOx:H/n+-nc-Si:H trilayer structure exhibits the potential to boost highly efficient solar cells. The bottom highly crystallized, lightly phosphorus-doped n-nc-Si:H film promotes rapid nucleation of the intermediate n-nc-SiOx:H film and thus reduces the thickness of the incubation layer, as well as improves the passivation contact. The n-nc-SiOx:H film in the middle layer provides excellent optical properties and reduces parasitic absorption, thereby increasing the short-circuit current density. Furthermore, the highly doped n+-nc-Si:H at the top offers an optimal ohmic contact with the reactive plasma deposition-grown TCO layer, which ultimately enhances the fill factor. Ultimately, a conversion efficiency of 20.41%, with an open-circuit voltage of 720 mV, a short-circuit current density of 39.34 mA/cm2, and a filling factor of 72.05%, was achieved in the SHJ solar cell using a typical trilayer structure. This kind of trilayer structure has a particular significance for potential industrialized applications as it allows for efficient utilization of solar energy.

A versatile reactive layer toward ultra-long lifespan lithium metal anodes.

Unstable anode/electrolyte interfaces have significantly hindered the development of lithium (Li) metal batteries under high rates and large capacities. In this study, a versatile reactive layer based on sulfur-selenium crosslinked polyacrylonitrile brushes has been developed by a combined strategy of polymer topology design and chemical crosslinking. The sulfur-selenium crosslinked polyacrylonitrile side-chains can react with Li to generate passivated Li2S-Li2Se-containing solid electrolyte interphase while 3D lithiophilic porous nanonetworks enable Li penetration, contributing to achieving rapid and uniform Li ion flux and a dendrite-free anode. With these merits, ultralong-term stable cycling (over 1 year and 4 months) at a high current density of 10mA cm-2 has been achieved for the protected Li anodes. Moreover, even when tested in high-loading Li|NCM622 cell (21.6mg cm-2) and Li-S cell with a low negative to positive electrode capacity ratio (1.4), stable cycling performances can also be achieved.

Mesoscale simulation study on formation of reactive double-layered liner

Abstract A mesoscale numerical simulation model of double-layered liner with reactive material and copper is established by means of mesoscale numerical simulation method. The mesoscale morphology, velocity characteristics and the force-thermal coupling characteristics of reactive material during the formation process are studied by simulating the double-layered liner with typical structure. Six kinds of double-layered liner with different liner thickness ratios are simulated to study the influence of liner thickness relationship on formation. The main results are as follows: The slug is almost completely formed by the reactive outer layer liner, and the jet head is completely formed by the inner liner. The slug speed is about 450m/s, the jet head speed is about 5000m/s, PTFE and Al material speed is basically the same, there is no velocity gradient; The pressure and temperature of reactive outer layer liner are positively correlated. The impact temperature rise of reactive material is low due to the wave impedance characteristics of double-layered liner, which may lead to a low degree of activation. In addition, the jet length and head velocity decrease with the increase of total liner thickness. The liner thickness is increased from 1mm/3mm to 2mm/5mm, the jet length is shortened by 20%, and the head speed is reduced by 15%; At the same time, the thickness of copper inner layer liner has a greater influence on the jet length, and too thick liner will have a negative effect on the pressure and temperature of the jet.

Compositional Optimization of Sputtered SnO2/ZnO Films for High Coloration Efficiency

We performed an electrochromic investigation to optimize the composition of reactive magnetron-sputtered mixed layers of zinc oxide and tin oxide (ZnO-SnO2). Deposition experiments were conducted as a combinatorial material synthesis approach. The binary system for the samples of SnO2-ZnO represented the full composition range. The coloration efficiency (CE) was determined for the mixed oxide films with the simultaneous measurement of layer transmittance, in a conventional three-electrode configuration, and an electric current was applied by using organic propylene carbonate electrolyte cells. The optical parameters and composition were measured and mapped by using spectroscopic ellipsometry (SE). Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) measurements were carried out to check the SE results, for (TiO2-SnO2). Pure metal targets were placed separately from each other, and the indium–tin-oxide (ITO)-covered glass samples and Si-probes on a glass holder were moved under the two separated targets (Zn and Sn) in a reactive argon–oxygen (Ar-O2) gas mixture. This combinatorial process ensured that all the compositions (from 0 to 100%) were achieved in the same sputtering chamber after one sputtering preparation cycle. The CE data evaluated from the electro-optical measurements plotted against the composition displayed a characteristic maximum at around 29% ZnO. The accuracy of our combinatorial approach was 5%.

Sustenance of hydrogen–oxygen cellular detonation with ozone additions in confined space

The sustenance of cellular detonation under weak confinement is studied through two-dimensional (2D) numerical simulations of hydrogen–oxygen mixtures surrounded by inert gas. The results show that in the weakly confined space, the cellular detonation with Chapman-Jouguet velocity can survive by increasing the width of the reactant layer and enhancing the reactivity of reactants, which ensures enough triple points and high reactivity in the reactant layer for detonation sustenance since transverse shocks cannot be regenerated and reinforced by boundary reflection. By adding ozone into the system and changing the width of the reactant layer, the relationship between induction length and detonation sustenance is established. It is found that the sustenance of cellular detonation in the weakly confined space is related to the ratio of the reactant layer width to the induction length. Ozone reactions can reduce the induction length and enhance reactivity, thereby promoting the generation of new transverse shocks and significantly improving the sustenance of cellular detonation in weakly confined space.

Thermally and chemically reactive boundary layer flow past a wedge moving in a nanofluid with activation energy and thermophoretic diffusion effects

This study investigates the effects of activation energy and chemical reactions on the boundary layer flow around a wedge that is moving in a nanofluid. To represent the problem, nonlinear partial differential equations are utilized. These equations can be reduced to nonlinear coupled ordinary differential equations using similarity transformations. These equations are numerically solved using the Keller Box technique, and then their numerical and pictorial solutions are studied using MATLAB. The study looks at the relationship between the velocity, temperature, and concentration profiles and important factors such as the Prandtl number, constant moving parameter, activation energy, and reaction rate. The parametric range of factors such as 0.1 ≤ λ ≤ 1.0, 0.1 ≤ Le ≤ 3.0, 0.1 ≤ E ≤ 2.0, 0.1 ≤ Pr ≤ 7.0, 0.1 ≤ Nt ≤ 0.5, 0.1 ≤ Nb ≤ 1.0, 0.1 ≤ σ ≤ 3.4, 0.1 ≤ δ ≤ 2.5, and 0.1 ≤ β ≤ 2.0 is utilized. Furthermore, a comprehensive investigation is conducted into the remedies for skin friction and heat transmission rate. It is deduced that a growing magnitude in moving fluid velocity is noted for lower Prandtl, moving factor, reaction factor, and greater activation energy. It is depicted that the maximum enhancing magnitude in temperature and concentration with good distributions is examined for each pertinent factor. The growing magnitude of heat transport is noted for lower Lewis and temperature-difference factors but increases as pressure-gradient and Brownian factor rise.

Unveiling Na‐ion storage mechanism and interface property of layered perovskite Bi2TiO4F2@rGO anode in ether‐based electrolyte

Abstract To unveil the charge storage mechanisms and interface properties of electrode materials is very challenging for Na‐ion storage. In this work, we report that the novel layered perovskite Bi2TiO4F2@reduced graphene oxides (BTOF@rGO) serves as a promising anode for Na‐ion storage in an ether‐based electrolyte, which exhibits much better electrochemical performance than in an ester‐based electrolyte. Interestingly, BTOF@rGO possesses a prominent specific capacity of 458.3–102 mAh g−1/0.02–1 A g−1 and a high initial coulombic efficiency (ICE) of 70.3%. Cross‐sectional morphology and depth profile surface chemistry indicate not only a denser reactive interfacial layer but also a superior solid electrolyte interface film containing a higher proportion of inorganic components, which accelerates Na+ migration and is an essential factor for the improvement of ICE and other electrochemical properties. Electrochemical tests and ex situ measurements demonstrate the triple hybridization Na‐ion storage mechanism of conversion, alloying, and intercalation for BTOF@rGO in the ether‐based electrolyte. Furthermore, the Na‐ion batteries assembled with the BTOF@rGO anode and the commercial Na3V2(PO4)2F3@C cathode exhibit remarkable energy densities and power densities. Overall, the work shows deep insights on developing advanced electrode materials for efficient Na‐ion storage.