Interface Interaction Research Articles

Growth of Hg0.7Cd0.3Te on Van Der Waals Mica Substrates via Molecular Beam Epitaxy.

In this paper, we present a study on the direct growth of Hg0.7Cd0.3Te thin films on layered transparent van der Waals mica (001) substrates through weak interface interaction through molecular beam epitaxy. The preferred orientation for growing Hg0.7Cd0.3Te on mica (001) substrates is found to be the (111) orientation due to a better lattice match between the Hg0.7Cd0.3Te layer and the underlying mica substrate. The influence of growth parameters (mainly temperature and Hg flux) on the material quality of epitaxial Hg0.7Cd0.3Te thin films is studied, and the optimal growth temperature and Hg flux are found to be approximately 190 °C and 4.5 × 10-4 Torr as evidenced by higher crystalline quality and better surface morphology. Hg0.7Cd0.3Te thin films (3.5 µm thick) grown under these optimal growth conditions present a full width at half maximum of 345.6 arc sec for the X-ray diffraction rocking curve and a root-mean-square surface roughness of 6 nm. However, a significant number of microtwin defects are observed using cross-sectional transmission electron microscopy, which leads to a relatively high etch pit density (mid-107 cm-2) in the Hg0.7Cd0.3Te thin films. These findings not only facilitate the growth of HgCdTe on mica substrates for fabricating curved IR sensors but also contribute to a better understanding of growth of traditional zinc-blende semiconductors on layered substrates.

The interface interaction and thermal sensitivity of nitrogen-rich energetic co-particles: A reactive molecular dynamics simulation study

Composite explosives are the ultimate used form of energetic materials in weapon systems and aerospace or deep-sea explorers. Among them, the energetic co-particles which combine high-energy crystals with low-sensitivity energetic crystals, is a excellent way to balance energy and safety for energetic materials. In this work, a kind of nitrogen-rich octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX) / 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) co-particles were investigated using molecular modeling methods. Different ratios of HMX/LLM-105 co-particles were constructed by combining different high-energy HMX surfaces with low-sensitivity LLM-105 surfaces. Reactive molecular dynamics simulations (RMD) were carried out on the co-particle models to investigate the thermal sensitivity, as well as classical molecular dynamics simulations were performed to investigate the interfacial interactions. The results show that strong attractive forces including van der Waals and electrostatic interactions exist along the crystalline interfaces, and the thermal decomposition reactions were greatly influenced by the composition of the co-particles. Finally, recommended ratio of HMX/LLM-105, which has enough attractive interaction to enhance the interface, high energy as well as good thermal stability was selected. This research is of significance on the design of advanced insensitive energetic composites.

Efficient and Stable Inverted Perovskite Solar Cells Enabled by a Fullerene-Based Hole Transport Molecule.

Designing an efficient modification molecule to mitigate non-radiative recombination at the NiOx/perovskite interface and improve perovskite quality represents a challenging yet crucial endeavor for achieving high-performance inverted perovskite solar cells (PSCs). Herein, we synthesized a novel fullerene-based hole transport molecule, designated as FHTM, by integrating C60 with 12 carbazole-based moieties, and applied it as a modification molecule at the NiOx/perovskite interface. The in-situ self-doping effect, triggered by electron transfer between carbazole-based moiety and C60 within the FHTM molecule, along with the extended π conjugated moiety of carbazole groups, significantly enhances FHTM's hole mobility. Coupled with optimized energy level alignment and enhanced interface interactions, the FHTM significantly enhances hole extraction and transport in corresponding devices. Additionally, the introduced FHTM efficiently promotes homogeneous nucleation of perovskite, resulting in high-quality perovskite films. These combined improvements led to the FHTM-based PSCs yielding a champion efficiency of 25.58% (Certified: 25.04%), notably surpassing that of the control device (20.91%). Furthermore, the unencapsulated device maintained 93% of its initial efficiency after 1000 hours of maximum power point tracking under continuous one-sun illumination. This study highlights the potential of functionalized fullerenes as hole transport materials, opening up new avenues for their application in the field of PSCs.

Capillary reinforcement strategy guided construction of robust oxygen functionalized carbon-based porous foam for highly efficient solar evaporation

Recent research on carbon-based porous foams has made great progress to alleviate global clean water scarcity. However, it is still a challenge to produce carbon-based porous foams with both high evaporation performance and good mechanical property because of weak interface interactions between carbon-based material and matrix. Herein, we report an effective capillary enhancement strategy to construct robust oxygen-functionalized 3D carbon-based porous foams (OCPF) with abundant hydrophilic oxygen-functional groups from oxidized carbon fiber (OCF) and graphite oxide (GO). Owing to capillary enhancement strategy, a robust foam can be obtained, such as compression stress increases by 6–70 times, and compression modulus reaches 0.56–8.01 MPa, and the obtained foam also contains abundant oxygen-functionalized carbon materials to modulate water state. As a result, the optimized OCPFs show a high evaporation rate of ∼ 3.08 kg·m−2·h−1 with an efficiency of ∼ 94 % under one sun irradiation, which can be further raised to 7.89 kg·m−2·h−1 (5 cm height with 3 m·s−1 wind speed). Besides, the OCPFs also exhibit satisfied desalination and purification performance in actual saline water, domestic and industrial sewage, corrosive and oily wastewater. The feasible fabrication process, excellent performances, and potential applications of OCPFs could provide a new insight into the future development of high-performance and durable carbon-based solar evaporators for large-scale practical applications.

Study on plasma modified silica powder epoxy resin composites

This work uses micrometer scale silicon powder as raw material, conducts plasma interface modification in a nitrogen atmosphere, and adds nitrogen elements to generate active groups such as amino groups on its surface to improve the dispersion of silicon powder, enhance the interface interaction between silicon powder and epoxy resin, and form Si–N bonds. To a certain extent, the absorption performance of silicon powder has been improved, which indicates the effectiveness of plasma modification of Si powder. The hardness of the modified composite material increased from 75.52 to 85.34 HA. Mechanical experiments have shown that the addition of 3% wt significantly improves the tensile strength of epoxy resin, increasing it from 16.47 to 22.67 Mpa. Further increase in dosage will lead to a decrease in tensile strength. After modification, the 3%, 5%, and 10% modified epoxy composite materials increased from 22.67, 9.94, and 5.67 Mpa before modification to 24.15, 14.52, and 12.75 Mpa, respectively. Using molecular dynamics simulation to verify the feasibility of plasma modification on epoxy composite materials, it was found that the simulation results were consistent with the experimental results, and the ultimate tensile strength of the modified composite materials was improved. The electrochemical impedance spectroscopy and salt spray test results show that the low-frequency impedance modulus of the composite coating modified by plasma interface is about one order of magnitude higher than that of the unmodified silicon powder composite coating. The coating containing 5 wt% plasma modified silicon powder exhibits the best corrosion resistance.

Characterization of alternate encounter assemblies of SARS-CoV-2 main protease

The assembly of two monomeric constructs spanning segments 1-199 (MPro1-199) and 10-306 (MPro10-306) of SARS-CoV-2 main protease (MPro) was examined to assess the existence of a transient heterodimer intermediate in the N-terminal autoprocessing pathway of MPro model precursor. Together, they form a heterodimer population accompanied by a 13-fold increase in catalytic activity. Addition of inhibitor GC373 to the proteins increases the activity further by ∼7-fold with a 1:1 complex and higher order assemblies approaching 1:2 and 2:2 molecules of MPro1-199 and MPro10-306 detectable by analytical ultracentrifugation and native mass estimation by light scattering. Assemblies larger than a heterodimer (1:1) are discussed in terms of alternate pathways of domain III association, either through switching the location of helix 201-214 onto a second helical domain of MPro10-306 and vice versa or direct interdomain III contacts like that of the native dimer, based on known structures and AlphaFold 3 prediction, respectively. At a constant concentration of MPro1-199 with molar excess of GC373, the rate of substrate hydrolysis displays first order dependency on the MPro10-306 concentration and vice versa. An equimolar composition of the two proteins with excess GC373 exhibits half-maximal activity at ∼6 μM MPro1-199. Catalytic activity arises primarily from MPro1-199 and is dependent on the interface interactions involving the N-finger residues 1-9 of MPro1-199 and E290 of MPro10-306. Importantly, our results confirm that a single N-finger region with its associated inter-subunit contacts is sufficient to form a heterodimeric MPro intermediate with enhanced catalytic activity.

Effect of diacylglycerol on partial coalescence of aerated emulsions: Fat crystal-membrane interaction and air-liquid Interface interaction insights

Currently, the poor whipping capabilities of anhydrous milk fat (AMF) in aerated emulsion products are a major obstacle for their use in beverages like tea and coffee, as well as in cakes and desserts, presenting fresh hurdles for the food industry. In this study, the mechanism of action of diacylglycerols (DAGs) with different carbon chain lengths and degrees of saturation on the partial coalescence of aerated emulsions was systematically investigated from three fundamental perspectives: fat crystallization, air-liquid interface rheology, and fat globule interface properties. The optimized crystallization of long carbon chain length diacylglycerol (LCD) based on stearate enhances interactions between fat globules at the air-liquid interface (with an elastic modulus E' reaching 246.42 mN/m), leading to a significantly reduced interface membrane strength. This promotes fat crystal-membrane interactions during whipping, resulting in a thermally stable foam structure with excellent shaping capability due to enhanced partial coalescence of fat globules. Although Laurate based medium carbon chain length diacylglycerol (MCD) promoted fat crystallization and optimized interface properties, it showed weaker foam properties because it did not adequately encapsulate air bubbles during whipping. Conversely, oleate long carbon chain length diacylglycerol (OCD) proved to be ineffective in facilitating fat crystal-membrane interaction, causing foam to have a subpar appearance. Hence, drawing from the carefully examined fat crystal-membrane interaction findings, a proposed mechanism sheds light on how DAGs impact the whipping abilities of aerated emulsions. This mechanism serves as a blueprint for creating aerated emulsions with superior whipping capabilities and foam systems that are resistant to heat.

Crack configuration influence on fracture behavior and stress shielding: insights from molecular dynamics simulations

The fracture behavior of the Ti–Al alloy is significantly affected by its nano-lamellar structure. However, further investigation is still required to fully comprehend how the initial crack configuration influences the lamellar Ti–Al’s deformation behavior. Although molecular dynamics simulations are a great way to study crack-tip interactions in interface-dominated microstructures, the design of the simulation can have an impact on the behavior that is predicted. To shed light on this matter and at the same time to understand the impact of the specific interface structure, a systematic study of crack-tip interface interactions in nano-lamellar two-phase Ti–Al was carried out. The type of interface and crack configuration were varied in these simulations to distinguish between the effects of the microstructure and the crack geometry. Results show that the semi-coherent pseudo twin ( γ/ PT) interface is the strongest barrier for crack propagation while the coherent true twin interface ( γ/ TT) is the weakest. After a thorough review of the contributing factors, it is evident that the orientation of the crack has a greater impact on its propagation than the aspect ratio of the crack. The stress shielding effectiveness of lamellar interfaces is strongly dependent on the crack configuration. However, regardless of the initial crack set-up, the coherent γ/ TT interface appears to be the most effective interface in terms of shielding.

Impact of Water-Water Correlation at Suspended Graphene/Water Interface Under Different Electro-Modulated

Graphene-based devices have extensive applications in aqueous environments. The molecular interactions across the graphene sheet significantly impact various devices, although few researches focused on elucidating the interface effects. In this study, we utilize trench structure to make graphene unilaterally and bilaterally suspended in water. The conduction status of both lateral and longitudinal currents (Id, Is, Ig) of graphene was monitored under two suspension scenarios to investigate the changes in interface evolution with the introduction of solvent-solvent interactions. For unilaterally suspended graphene, the current perpendicular to the graphene channel direction remains in the off state. For bilaterally suspended graphene, the current path is formed vertically between the graphene channel and the gate electrode, perpendicular to the direction of the graphene. This experimental setup illustrates the possibilities for exploring interfacial characteristics at the interface between 2D materials and solutions through practical experimentation.The detailed fabrication process of the graphene field-effect-transistor (GFET) device is depicted in Fig. 1. To fabricate the microchannel structure, a microfluidic pattern was generated through photolithography on the SiO2/Si substrate spun with a layer of photoresist. Then, the corresponding microchannel pattern with a thickness of 300 nm SiO2 and 30 μm Si layer was etched by reactive-ion etching (RIE) to form a trench capable of storing water. Afterward, Au electrodes were placed next to the microfluidic channel via evaporation utilizing a shadow mask. The second critical step involves the preparation of graphene. Graphene sheets were grown on a copper foil through the chemical vapor deposition (CVD) method. With the support of PMMA film, physically stacked graphene bilayer graphene was transferred to the target substrate. Ultimately, the suspended bilayer graphene was submerged in acetone for 24 hours to remove the PMMA layer and immersed in isopropanol (IPA) and DI water to clean the residues.According to this device structure, we successfully fabricate the suspension of graphene unilaterally or bilaterally in water. When introducing water through the trench, the bottom surface of the suspended graphene contacts with water molecules, while the upper surface of the suspended graphene is exposed to air. This configuration leads to a unilateral suspension in water (unilateral-suspension GFET). Conversely, when water is introduced through the trench and water is also added above the graphene channel, graphene comes into contact with water on both sides. This configuration results in its bilateral suspension in the water (bilateral-suspension GFET). The electronic transport characteristics of unilateral-suspension GFET and bilateral-suspension GFET were measured by Agilent semiconductor analysis B1500A. The gate voltage was applied to water through an Ag/AgCl electrode. Fig. 2 (a) displays the Raman spectroscopy of suspended graphene on GFET device. The most notable features of the Raman spectrum are the G peak around 1580 cm-1, and the 2D band around 2700 cm-1, which are typical characteristics of graphene. The ID/IG ratio of 0.19 indicates the good quality of the graphene layers. As shown in Fig. 2 (b), the scanning electron microscope (SEM) result of suspended graphene on the GFET device verifies the presence of large-area graphene. The diagram displays a clear demarcation line, facilitating the identification of graphene presence on the substrate. This can also imply the excellent quality of graphene with few defects.The transport behavior of unilateral-suspension GFET and bilateral-suspension GFET are measured individually, as shown in Fig. 3. The sum (ΔI) of The drain current behavior (Id) and source current behavior (Is), and gate current behavior (Ig) are recorded with changed gate voltages (from -1V to +1V) and constant VDS (VDS= 0.1V). For unilateral-suspension GFET, ΔI and Ig keep constant at zero, and there is no conduction path perpendicular to the graphene channel direction. For bilateral-suspension GFET, ΔI and Ig at positive gate voltage are opposite in direction and equal in absolute value, this indicates the formation of an obvious path between the channel and gate electrode. The apparent interfacial evolution is believed to change with the introduction of the other side of water.In conclusion, we compare the electrical characteristics shown by two different suspension situations of graphene-based field effect transistors. There are some interesting results of the conduction path relating to interfacial evolution. This result has potential for chemical sensing or battery application. Furthermore, it can contribute to fundamental research about the interface interaction between suspended graphene and water. Figure 1

THE EFFECT OF CHEMICAL STRUCTURE OF VINYL CHLORIDE BASED POLYMERS ON ITS THE COMPATIBILITY WITH POLYURETHANEUREA ELASTOMER

The effect of the chemical structure of vinyl chloride-based polymers, such as poly(vinyl chloride) (PVC), chlorinated PVC (cPVC), vinyl chloride/vinylidene chloride copolymer VCVD-40TM, vinyl chloride/vinyl acetate copolymer А-15TM on its compatibility with poly(ether-urethane)urea elastomer (PUU) was studied by DSC and FTIR spectroscopy. The segmented PUU was synthesized by prepolymer approach in N,N-dimethylformamide (DMF) solution using poly(propylene glycol) of number-averaged molecular weight (Mn) of 1000 Da, 2,4-tolylenediisocyanate and tolylene 2,4-diamine as a chain extender at a molar ratio of 1:2:1. PUU/vinyl chloride-based polymer blends was prepared by solution casting technique vie DMF solution. It was found a compatibility of PUU based blends containing 30 % PVC (PUU/30PVC blend) or cPVC (PUU/30cPVC) were initiated by strong hydrogen bonding. As a result, the blends are characterized by single wide relaxation transition. A glass transition temperature (Тс) of PUU/30PVC composite is similar to the theoretical one (ТFс), which is calculated using the Flory-Fox equation, whereas Тс value of PUU/30cPVC composite is higher than ТFс. Introducing polar vinyl acetate or vinylidene chloride fragments into vinyl chloride-based polymer macrochains suppresses the compatibility of components of the polymer blends and initiates the formation of a biphase microheterogeneous structure. The formation of intermolecular hydrogen bonding network at the interface in polymer-polymer blends is confirmed by FTIR spectroscopy. Comparative analysis of experimental and theoretically calculated (additive) tensile characteristics of polymer blends demonstrates their substantial dependence on interface interactions between the constituents. The highest strengthening effect was observed for cPVC or PVC-containing nanocomposites.

Immobilizing DNase in ternary AuAgCu hydrogels to accelerate biofilm disruption for synergistically enhanced therapy of MRSA infections

Bacterial biofilm-related infections have become a significant global concern in public health and economy. Extracellular DNA (eDNA) is regarded as one of the key elements of extracellular polymeric substances (EPS) in bacterial biofilm, providing robust support to maintain the stability of bacterial biofilms for fighting against environmental stresses (such as antibiotics, reactive oxygen species (ROS), and hyperthermia). In this study, ternary AuAgCu hydrogels nanozyme with porous network structures were utilized for the immobilization of DNase (AuAgCu@DNase hydrogels) to realize enhanced biofilm decomposition and antibacterial therapy of MRSA. The prepared AuAgCu@DNase hydrogels can efficiently hydrolyze eDNA in biofilms so that the generated ROS and hyperthermia by laser irradiation can permeate into the interior of the biofilm to achieve deep sterilization. The typical interface interactions between AuAgCu hydrogels and DNase and the excellent photothermal-boost peroxidase-like performances of AuAgCu hydrogels take responsibility for the enhanced antibacterial activity. In the MRSA-infected wounds model, the in vivo antibacterial results revealed that the AuAgCu@DNase hydrogels possess excellent drug-resistant bacteria-killing performance with superb biocompatibility. Meanwhile, the pathological analysis of collagen deposition and fibroblast proliferation of wounds demonstrate highly satisfactory wound healing. This work offers an innovative path for developing nanozyme-enzyme antibacterial composites against drug-resistant bacteria and their biofilms.

Imbibition models quantifying interfacial interactions: Based on nuclear magnetic resonance investigation and coupled structural characteristics

An investigation into spontaneous imbibition in porous media is of paramount scientific significance in various projects. However, a precise understanding of the interaction mechanisms between media structural characteristics and imbibition remains elusive, and quantitative analysis of the interfacial interaction is lacking. Therefore, to mitigate the influence of dispersion, this study first investigates cyclic imbibition experiments of coal samples to explore the interaction mechanism between pore-fracture structure (PFS) and imbibition. Nuclear magnetic resonance is used to visualize water transport during imbibition across all scales. Subsequently, the slake durability index is suggested to clarify the coupling relationship between water–coal interactions and imbibition. Two more comprehensive and accurate imbibition models are established, based on pore size and comprehensive seepage parameters, respectively. The results demonstrate that both new models exhibit superior conformity with experimental data compared to traditional models. The memory factor quantifies interface interaction within these models. Sensitivity analysis reveals that strong interface interaction diminishes the effective imbibition ratio, while the structural characteristics of porous media significantly influence the interaction. Furthermore, the fractal dimension quantitatively characterizes the PFS features of coal samples. An exploration of the relationship between fractal dimension and memory factor indicates the influence of porous media heterogeneity on imbibition.

Stabilization of interconnected models with Nitsche's interface conditions using the two-grid approach: A finite element study

In this paper, a stabilized Stokes–Stokes system with Nitsche's type interface conditions is presented. These conditions are commonly employed in many multi-physical fields, including fluid–fluid interaction, fluid–structure interaction, oceanographic modeling, and atmospheric forecasting. For multi-physical domain modeling purposes, Nitsche's interface conditions provide useful benefits over classical conditions via addressing the complicated nature of fluid phase interface mathematical modeling, phase boundary tracking, interface interactions, and mass and energy transportation. It is not easy to find analytical and numerical solutions for models with these characteristics. We use more accurate interface conditions to solve the fluid–fluid interaction model to accomplish this numerically. This is achieved by including new terms at the interface and decoupling the domain through the two-grid technique, which ultimately reduces the main issue into several smaller problems. Comparing this method to existing models, we find that it is computationally feasible because it uses less memory and operates with a coarse grid instead of a fine grid and thus improves convergence rates for complex and nonlinear problems. Furthermore, it shows mesh independence, supports potential parallelization, and is crucial for advanced multigrid techniques. The optimality of the error is confirmed both theoretically and numerically. The numerical experimental section validates the model through three types of numerical experiments.

Optimization of electrical control equipment interface layout with cognitive load based on pso algorithm

Abstract Addressing the complexity of current impregnation machine electrical control interfaces, this study proposes optimization methods for their layout design. It incorporates factors affecting cognitive load during interface interaction, formulating three principles: highlighting essential elements, operation sequence, and element relevance. These principles guide the construction of a mathematical model for the optimization of electrical equipment control interface layouts. The Particle Swarm Optimization algorithm is applied to solve the model’s objective function, producing optimized layouts, which are then validated through eye-tracking experiments. The results demonstrate the method’s effectiveness in optimizing control interface layouts, aligning with operators’ intuitive logic.

Development of an Engineered Sugar Aminotransferase with Simultaneously Improved Stability and Non-Natural Substrate Activity to Synthesize the Glucosidase Inhibitor Valienamine

Sugar aminotransferases (SATs) catalyze the installation of chiral amines onto specific keto sugars, producing bioactive amino sugars. Their activity has been utilized in artificial reactions, such as using the SAT WecE to transform valienone into the valuable α-glucosidase inhibitor valienamine. However, the low thermostability and limited activity on non-natural substrates have hindered their applications. Simultaneously improving stability and enzyme activity is particularly challenging owing to the acknowledged inherent trade-off between stability and activity. A customized combinatorial active-site saturation test-iterative saturation mutagenesis (CAST-ISM) strategy was used to simultaneously enhance the stability and activity of WecE toward valienone. Fourteen hotspots related to improving the stability–\\activity trade-off were identified based on evolutionary conservation and the average mutation folding energy assessment of 57 residues in the active site of WecE. Positive mutagenesis and combinatorial mutations of these specific residues were accomplished via site-directed saturation mutagenesis (SSM) and iterative evolution cycles. Compared with those of the wild-type (WT) WecE, the quadruple mutant M4 (Y321F/K209F/V318R/ F319V) displayed a 641.49-fold increase in half-life (t1/2) at 40 °C and a 31.37-fold increase in activity toward the non-natural substrate valienone. The triple mutant M3 (Y321F/K209F/V318R) demonstrated an 83.04-fold increase in (t1/2) at 40 °C and a 37.77-fold increase in activity toward valienone. The underlying mechanism was dependent on the strengthened interface interactions and shortened transamination reaction catalytic distance, compared with those of the WT, which improved the stability and activity of the obtained mutants. Thus, we accomplished a general target-oriented strategy for obtaining stable and highly active SATs for artificial amino-sugar biosynthesis applications.

Precisely constructed core-shell organic/inorganic heterojunction for heightened photoreduction of Cr(VI): Synergy of reinforced interface interaction and high-speed carrier transfer

Photocatalysis technology has been widely studied for treating Cr(VI) pollution in water and constructing heterogeneous structures presents a compelling approach to enhance the efficiency of Cr(VI) treatment. Pitifully, solely utilizing heterostructure, especially random composites of heterogeneous photocatalysts, often falls short of effectively enhancing the separation efficiency of photogenerated carriers. Furthermore, most photocatalysts interact weakly with the Cr(VI) anions, greatly reducing the utilization efficiency of photogenerated carriers. Herein, pyridine-based conjugated imprinted polymer (CIP) photocatalyst was precisely coated on urchin-like TiO2 using an in-situ condensation approach, forming a compact core–shell structure of organic/inorganic heterojunction. On the one hand, the compact heterojunction structure of the core–shell effectively improved the separation efficiency of photogenerated carriers. On the other hand, CIP enhanced the adsorption between the photocatalyst and Cr(VI), effectively improving the utilization efficiency of photogenerated carriers. Due to the collaborative effects of selective adsorption and core–shell heterojunction photocatalysis, the photocatalyst demonstrated remarkable performance in eliminating Cr(VI). For high concentration Cr(VI) pollution of 100 ppm, complete elimination could be achieved within 90 min. This research presented an innovative and efficient approach for the precise synthesis of photocatalysts.

Chemically bonded CdBiO2Br/BiOI heterojunction with strong interfacial electric field for enhanced photocatalysis

Semiconductor-based photocatalysis shows a large potential for contaminant purification, however, a single semiconductor photocatalyst suffers from low utilization efficiency of photogenerated carriers, leading to inferior photocatalytic activity. Herein, CdBiO2Br@BiOI (CBOB@BiOI) heterojunction with a close interface interaction is prepared by a facile precipitation method at the ambient atmosphere. X-ray photoelectron spectroscopy and Density Functional Theory calculations on work function consistently disclose that the formation of CdBiI bonds at the interface induces the electron migration from BiOI to CdBiO2Br, which allows CBOB@BiOI heterojunction to have a strong interfacial electric field (IEF) for efficiently separating photocharges. In-situ Kelvin-probe Force Microscopy measurement demonstrates that CBOB@BiOI heterojunction shows a larger surface potential than CdBiO2Br and BiOI in dark and a potential decrease under illumination, which can be ascribed to the photoinduced electron migration within heterojunction driven by the IEF. Thus, the CBOB@BiOI heterojunction shows a much more efficient photocatalytic activity for the breakdown of tetracycline hydrochloride (TC), which is 2.44 and 3.99 times higher than CdBiO2Br and BiOI, respectively. Electron Paramagnetic Resonance test also confirms that the CBOB@BiOI heterojunction produces much more superoxide radicals and holes as reactive species than CdBiO2Br and BiOI. Furthermore, the latent degradation pathways of TC are investigated by Liquid Chromatograph Mass Spectrometer. This work may provide new ideas for constructing intimately bonded heterojunction photocatalysts with a strong IEF for efficient photocatalytic activity.

Interface-reinforced high-capacity fiber cathode for wearable Li–S batteries

ABSTRACT Fiber-shaped Li–S batteries are attractive for constructing smart textiles as flexible power solutions due to their high theoretical specific capacity, flexibility and wearability. However, severe interfacial issues, such as the shuttle effect of polysulfides on the cathode side, lead to capacity decay and poor lifespan of the batteries. Herein, we report a fiber-shaped composite cathode with collaborative interface interactions to maintain electrode integrity and boost electrochemical performance. In this architecture, nanosulfur-polyvinylpyrrolidone (nanoS-PVP) particles are uniformly implanted into the few-layer Ti3C2Tx with outstanding electrical conductivity and then coated on aluminum (Al) fiber current collectors. Impressively, nanoS and soluble polysulfides are restricted to the cathode side via synergy physical confinement and chemical adsorption of Ti3C2Tx. The PVP chains on the surface of the nanoS prevent the sulfur from agglomeration and bridge the Ti3C2Tx by abundant hydrogen bonds. The enhanced interface endows the cathode with excellent mechanical flexibility, good adsorption of polysulfides and fast reaction kinetics. Consequently, the prepared Ti3C2Tx/nanoS-PVP@Al cathode exhibits excellent cycling performance (capacity retention of 92.8% after 1000 cycles at 1 C), high-rate capacity (556.2 mAh g−1 at 2.0 C) and high linear capacity (22.9 mAh m−1). Additionally, the fiber-shaped Li–S battery works effectively under deformation and high/low-temperature conditions. It can be integrated into the fabric to power light emitting diodes or charge a smartphone wirelessly.

Hydrogen peroxide activation by in-situ-loaded CuS/biochar photocatalyst: The critical role of sulfur species in regulating active species

Although metal sulfides have demonstrated exceptional catalytic properties in Fenton-like reactions, little is known about the role of sulfur species in transforming highly active species responsible for degradation organics. CuS (∼12 nm) nano-capsules embedded in the biochar (CuS-BC) were prepared from copper-rich biomass, which could activate H2O2 (4 mM) and completely remove tetracycline (TC) from water within 210 min. Compared with BC/H2O2/Vis system, the degradation efficiency of TC in the CuS-BC/H2O2/Vis system was improved by 14.8 times, and the utilization efficiency of H2O2 was improved by 86 times. The whole degradation process of TC can be divided into two stages: quasi-first-order reaction kinetics (kobs = 0.015 min−1) and zero-order reaction kinetics (kobs = 6.457 mol/L/min). Within 90 min, H2O2 is activated to produce hydroxyl radicals (OH) by surface Cu2+ on CuS and photogenerated electrons (e−) generated from CuS photoexcitation, which react immediately with surface SO32− to form SO4−. After 90 min, CuIII-peroxo species (CuIII-O22−-(SO32−)n) formed by electron transfer between CuI, O2, and surface SO32− oxidize the remaining 50 % TC through interface interaction. CuS-BC catalyst exhibits excellent photostability and suitability for actual antibiotic wastewater. Overall, this study offers mechanistic insight into the role of sulfur species in the sulfide-based Fenton reactions.

Deciphering the enigmatic PilY1 of Acidithiobacillus thiooxidans: An in silico analysis

Thirty years since the first report on the PilY1 protein in bacteria, only the C-terminal domain has been crystallized; there is no study in which the N-terminal domain, let alone the complete protein, has been crystallized. In our laboratory, we are interested in characterizing the Type IV Pili (T4P) of Acidithiobacillus thiooxidans. We performed an in silico characterization of PilY1 and other pilins of the T4P of this acidophilic bacterium. In silico characterization is crucial for understanding how proteins adapt and function under extreme conditions. By analyzing the primary and secondary structures of proteins through computational methods, researchers can gain valuable insights into protein stability, key structural features, and unique amino acid compositions that contribute to resilience in harsh environments. Here, it is presented a description of the particularities of At. thiooxidans PilY1 through predictor software and homology data. Our results suggest that PilY1 from At. thiooxidans may have the same role as has been described for other PilY1 associated with T4P in neutrophilic bacteria; also, its C-terminal interacts (interface interaction) with the minor pilins PilX, PilW and PilV. The N-terminal region comprises domains such as the vWA and the MIDAS, involved in signaling, ligand-binding, and protein-protein interaction. In fact, the vWA domain has intrinsically disordered regions that enable it to maintain its structure over a wide pH range, not only at extreme acidity to which At. thiooxidans is adapted. The results obtained helped us design the correct methodology for its heterologous expression. This allowed us partially experimentally characterize it by obtaining the N-terminal domain recombinantly and evaluating its acid stability through fluorescence spectroscopy. The data suggest that it remains stable across pH changes. This work thus provides guidance for the characterization of extracellular proteins from extremophilic organisms.