Electric Layer Research Articles

Mild polarization electric field in ultra-thin BN-Fe-graphene sandwich structure for efficient nitrogen reduction

The electrocatalytic N2 reduction reaction (NRR) is expected to supersede the traditional Haber-Bosch technology for NH3 production under ambient conditions. The activity and selectivity of electrochemical NRR are restricted to a strong polarized electric field induced by the catalyst, correct electron transfer direction, and electron tunneling distance between bare electrode and active sites. By coupling the chemical vapor deposition method with the poly(methyl methacylate)-transfer method, an ultrathin sandwich catalyst, i.e., Fe atoms (polarized electric field layer) sandwiched between ultrathin (within electron tunneling distance) BN (catalyst layer) and graphene film (conducting layer), is fabricated for electrocatalytic NRR. The sandwich catalyst not only controls the transfer of electrons to the BN surface in the correct direction under applied voltage but also suppresses hydrogen evolution reaction by constructing a neutral polarization electric field without metal exposure. The sandwich electrocatalyst NRR system achieve NH3 yield of 8.9 μg h−1 cm−2 and Faradaic Efficiency of 21.7%. The N2 adsorption, activation, and polarization electric field changes of three sandwich catalysts (BN-Fe-G, BN-Fe-BN, and G-Fe-G) during the electrocatalytic NRR are investigated by experiments and density functional theory simulations. Driven by applied voltage, the neutral polarized electric field induced by BN-Fe-G leads to the high activity of electrocatalytic NRR.

Enhancing Energy Density in Aqueous Ammonium-Ion Supercapacitors via CuCo2S4@MoS2 Core@Shell Heterostructure Design.

Aqueous ammonium-ion supercapacitors (AASCs) are recognized for their rapid charge-discharge capability, long cycle life, and excellent power density. However, they still confront the challenges of low energy density. To address the above issue, this work proposes a novel strategy involving the establishment of CuCo2S4@MoS2 core@shell heterostructures to enhance the capacity of electrode material. The double electric layer energy storage mechanism of the MoS2 shell facilitates the storage and provision of a substantial ammonium source for NH4 + insertion into CuCo2S4, thereby enhancing the electrochemical performance of AASCs. The density functional theory (DFT) calculations demonstrate that the CuCo2S4@MoS2 core@shell heterostructures exhibit better affinity for NH4 + and improved conductivity. Furthermore, the internal electric field at the heterojunction accelerates NH4 + transfer, thereby enhancing the pseudocapacitive behavior of CuCo2S4. Owing to the abundant active sites and pronounced pseudo-capacitance, the CuCo2S4@MoS2 electrode achieves a specific capacity of 2045 C g-1 at 1 A g-1. With activated carbon (AC) as the negative electrode, the fabricated CuCo2S4@MoS2//AC AASC device attains a specific capacity of 591 C g-1 and an energy density of 83.23Wh kg-1. This work presents a promising new strategy for the next generation of AASCs.

Water-Triboelectrification-Complemented Moisture Electric Generator.

Energy harvesting from ubiquitous natural water vapor based on moisture electric generator (MEG) technology holds great potential to power portable electronics, the Internet of Things, and wireless transmission. However, most devices still encounter challenges of low output, and a single MEG complemented with another form of energy harvesting for achieving high power has seldom been demonstrated. Herein, we report a flexible and efficient hybrid generator capable of harvesting moisture and tribo energies simultaneously, both from the source of water droplets. The moisture electric and triboelectric layers are based on a water-absorbent citric acid (CA)-mediated polyglutamic acid (PGA) hydrogel and porous electret expanded polytetrafluoroethylene (E-PTFE), respectively. Such a waterproof E-PTFE film not only enables efficient triboelectrification with water droplets' contact but also facilitates water vapor to be transferred into the hydrogel layer for moisture electricity generation. A single hybrid generator under water droplets' impact delivers a DC voltage of 0.55 V and a peak current density of 120 μA cm-2 from the MEG, together with a simultaneous AC output voltage of 300 V and a current of 400 μA from the complementary water-based triboelectric generator (TEG) side. Such a hybrid generator can work even under harsh wild environments with 5 °C cold and saltwater impacts. Significantly, an optical alarm and wireless communication system for wild, complex, and emergency scenarios is demonstrated with power from the hybrid generators. This work expands the applications of water-based electricity generation technologies and provides insight into harvesting multiple potential energies in the natural environment with high output.

Z-scheme driven charge transfer in g-C3N4/α-Fe2O3 nanocomposites enabling photocatalytic degradation of crystal violet and chromium reduction

In this study, we demonstrated the design and fabrication of iron oxide-embedded protonated graphitic carbon nitride (α-Fe2O3/p-g-C3N4) nanocomposites for photocatalytic dye degradation and heavy metal reduction applications under sunlight irradiation. The developed nanocomposites, with varying weight percentages of α-Fe2O3, were characterized for their structural (XRD, FTIR, XPS), optical (absorption and photoluminescence), morphological (FE-SEM, TEM), and electrochemical (EIS) properties to elucidate their structure-property relationships. The synthesis method ensures the uniform dispersion of α-Fe2O3 nanoparticles, with a particle size range of 50–60 nm, onto p-g-C3N4. XPS analysis suggests the formation of an electrical layer at the interface of α-Fe2O3/p-g-C3N4, facilitating the formation of a Z-scheme heterojunction. The photoluminescence and EIS spectra of the nanocomposite indicated effective separation and transfer of photo-induced charge carriers, aided by a reduced bandgap energy of ∼2.63 eV. Notably, the optimized 10 wt% α-Fe2O3/p-g-C3N4 nanocomposite exhibited superior photocatalytic activity, degrading nearly 100 % of crystal violate dye and reducing 98 % of Cr(VI) ions, compared to bare p-g-C3N4, which degraded around 43 % of the dye and reduced 39 % of Cr(VI) ions under sunlight irradiation. Scavenger studies indicated that α-Fe2O3/p-g-C3N4 nanocomposites produce adequate superoxide anions and hydroxyl radicals for dye degradation and heavy metal ion reduction. The composite also demonstrated consistent recyclability up to 5 cycles with around 100 % cyclical efficiency. The pH-dependent photoreduction and cyclic dye degradation by the 10 wt% α-Fe2O3/p-g-C3N4 photocatalyst indicated excellent stability, making it suitable for the treatment of multi-pollutant wastewater.

Scalable Layered Heterogeneous Hydrogel Fibers with Strain-Induced Crystallization for Tough, Resilient, and Highly Conductive Soft Bioelectronics.

The advancement of soft bioelectronics hinges critically on the electromechanical properties of hydrogels. Despite ongoing research into diverse material and structural strategies to enhance these properties, producing hydrogels that are simultaneously tough, resilient, and highly conductive for long-term, dynamic physiological monitoring remains a formidable challenge. Here, a strategy utilizing scalable layered heterogeneous hydrogel fibers (LHHFs) is introduced that enables synergistic electromechanical modulation of hydrogels. High toughness (1.4MJ m-3) and resilience (over 92% recovery from 200% strain) of LHHFs are achieved through a damage-free toughening mechanism that involves dense long-chain entanglements and reversible strain-induced crystallization of sodium polyacrylate. The unique symmetrical layered structure of LHHFs, featuring distinct electrical and mechanical functional layers, facilitates the mixing of multi-walled carbon nanotubes to significantly enhance electrical conductivity (192.7 S m-1) without compromising toughness and resilience. Furthermore, high-performance LHHF capacitive iontronic strain/pressure sensors and epidermal electrodes are developed, capable of accurately and stably capturing biomechanical and bioelectrical signals from the human body under long-term, dynamic conditions. The LHHF offers a promising route for developing hydrogels with uniquely integrated electromechanical attributes, advancing practical wearable healthcare applications.

Molecular dynamics mechanism of incorporating ZnO with varying particle sizes into ECTFE coatings and its impact on corrosion resistance

A composite coating of zinc oxide/chlorotrifluoroethylene copolymer (ZnO/ECTFE) was prepared on the surface of carbon steel via electrostatic spraying and heat treatment at 260 ℃. The influence of ZnO particle size variations on the anticorrosive properties of ECTFE coating was investigated by characterizing the microstructure, adhesion, hydrophilic/hydrophobic properties, electrochemical corrosion performance, as well as the dynamics simulation analysis on water molecule and chloride ions diffusion in the coating. The results show that the ECTFE coating incorporated with 100nm ZnO has the highest surface roughness (Roughness coefficient Ra = 30.6nm), the most robust adhesion (Bonding pull-out strength = 5.22MPa), and the lowest corrosion current density after a 90-day immersion (Icorr,90d = 4.05 × 10⁻⁸ A∙cm⁻²). These improvements represent an increase of 81.67% and 59.9% compared to the pure copolymer coating (Icorr,90d = 2.21 × 10⁻⁷ A∙cm⁻²) and the coating incorporated with 200nm ZnO (Icorr,90d = 1.01 × 10⁻⁷ A∙cm⁻²), respectively. This phenomenon can be attributed to the addition of small-sized ZnO, which enhances the density of the coating, induces a hydrophobic transition on its surface, strengthens the double electric layer effect, thereby improving its resistance against water molecule and chloride ions diffusion and ultimately enhances the corrosion resistance.

From Bottom-Up Towards a Completely Decentralized Autonomous Electric Grid Based on the Concept of a Decentralized Autonomous Substation

The idea of a decentralized electric grid has shifted from being a concept to a reality. The growing integration of distributed energy resources (DERs) has transformed the traditional centralized electric grid into a decentralized one. However, while most efforts to manage and optimize this decentralization focus on the electrical infrastructure layer, the operational and control layer, as well as the data management layer, have received less attention. Current electric grids rely on centralized control centers (CCCs) that serve as the electric grid’s brain, where operators monitor, control, and manage the entire grid infrastructure. Hence, any disruption caused by a cyberattack or a natural event, disconnecting the CCC, could have numerous negative effects on grid operations, including socioeconomic impacts, equipment damage, market repercussions, and blackouts. This article introduces the idea of a fully decentralized electric grid that leverages autonomous smart substations and blockchain integration for decentralized data management and control. The aim is to propose a blockchain-enabled decentralized electric grid model and its potential impact on energy markets, sustainability, and resilience. The model presented underlines the transformative potential of decentralized autonomous grids in revolutionizing energy systems for better operability, management, and flexibility.

Revealing two-dimensional electric field crowding effect in breakdown performance of DPPT-TT polymer-based OFETs

The diketopyrrolopyrrole-based polymer (DPPT-TT) has been employed in organic power field effect transistors due to its exceptional off-state breakdown performance. The impact of organic semiconductor layer thickness on the breakdown performance has not been explored. In this study, we investigate the impact of DPPT-TT layer thickness on the breakdown voltage (BV) by fabricating organic field effect transistors (OFETs) with various DPPT-TT layer thicknesses. Our findings reveal that the devices' BV is a strong function of DPPT-TT layer thickness, and reducing the DPPT-TT layer thickness from 68 to 15 nm results in a decrease in BV from 291 to 86 V, attributed to the two-dimensional (2D) electric field crowding effect. An analytical model utilizing the 2D Poisson equation reveals an electric field at the DPPT-TT layer's surface. Thinner DPPT-TT layer exhibits larger electric field peak, leading to premature breakdown near the drain electrode. The relationship between breakdown electric field and DPPT-TT layer thickness was established by fitting the experimental data to the model, revealing an average BV error of only 8.8%. This phenomenon is validated to be ubiquitous in polymer based OFETs via DPPT-TT-based and P3HT-based devices. According to the proposed model, this 2D electric field crowding effect can be mitigated by adjusting the dielectric layer thickness (tD) and/or the dielectric material.

MemriSim: A theoretical framework for simulating electron transport in oxide memristors

We have developed a theoretical framework MemriSim for simulating the resistive switching behaviors of oxide memristors. MemriSim comprises two major parts, i) structural evolution of oxygen vacancies during conductive filament formation/rupture by kinetic Monte Carlo (kMC) algorithm, and ii) transport calculations based on the scenario of electron tunneling and thermionic emission with the kMC derived structures. As prototype probes, we have computed the current-voltage (I-V) curves of HfO2 and TaOx based memristors and compared the results with experimental measurements, which show perfect agreement. By tuning the physical parameters, MemriSim can describe resistive switching devices with different oxide layers and metal electrodes. In addition, the pulse transient current can also be simulated by considering the transient response of RLC circuit. The developed framework not only provides a general approach for understanding the fundamental mechanism of resistive switching in oxides, but also opens up new opportunities for designing and optimizing memristor-based architectures for nonvolatile memory, logic-in-memory and neuromorphic computing.Program summaryProgram Title: MemriSim.CPC Library link to program files: https://doi.org/10.17632/8gbbgf8z49.1Licensing provisions: GPLv2.Programming language: C++.Supplementary material: Supplementary material is available.Nature of problem: A general framework for simulating the resistive switching properties of oxide-based memristors; generate the structure of oxide layer during filament formation/rupture; calculate the I-V curves of memristive device; simulate the pulse transient current; predict the resistive switching performance of new devices.Solution method: The framework uses kMC algorithm for structural evolution, the electric field inside oxide layer is computed by the Poisson's equation, and the transport calculation is based on electron tunneling and thermionic emission.

High efficiency filtration and optimization of pelletizing performance of fine hematite concentrate using sulfuric acid filter aid: Behavior and mechanism

Following the application of anionic reverse flotation to fine low-grade hematite ore, a significant challenge emerges with elevated slurry viscosity and heightened moisture content in the resulting filter cakes. To address the challenge of dewatering during the filtration process of fine hematite concentrate, the impact of sulfuric acid filter aid dosage and filtration temperature on the filtration performance of hematite concentrate was systematically investigated in this study. In addition, the effect of sulfuric acid filter aid on the preparation of hematite pellets was also studied. The results revealed a significant decrease from 1.10 × 1010 1/m2 to 5.7 × 109 1/m2 in the specific resistance of the hematite filter cake when the sulfuric acid dosage was 1.2 g/kg and the filtration temperature was 20 °C. The mechanism underlying the enhancement of filtration performance of fine hematite concentrate by sulfuric acid was summarized. Sulfuric acid compressed the double electric layer on the surface of hematite concentrate particles, reducing the surface zeta potential and causing the aggregation of fine particles into larger ones. This led to an increase in filter cake porosity and compression of the hydration film thickness on particle surfaces, facilitating easier removal of filtrate from the filter cake. The appropriate dosage of bentonite for pelletizing was not significantly affected by sulfuric acid filter aid. Sulfuric acid improved the porosity, drying rate, and burst temperature of hematite green pellets. While the compressive strength of preheated pellets from sulfuric acid-assisted filtration of hematite concentrate showed a slight decrease, the compressive strength of roasted pellets was significantly increased.

Tuning the interfacial reaction environment via pH-dependent and induced ions to understand C–N bonds coupling performance in NO3− integrated CO2 reduction to carbon and nitrogen compounds over dual Cu-based N-doped carbon catalyst

Dual atomic catalysts (DAC), particularly copper (Cu2)-based nitrogen (N) doped graphene, show great potential to effectively convert CO2 and nitrate (NO3−) into important industrial chemicals such as ethylene, glycol, acetamide, and urea through an efficient catalytical process that involves C–C and C–N coupling. However, the origin of the coupling activity remained unclear, which substantially hinders the rational design of Cu-based catalysts for the N-integrated CO2 reduction reaction (CO2RR). To address this challenge, this work performed advanced density functional theory calculations incorporating explicit solvation based on a Cu2-based N-doped carbon (Cu2N6C10) catalyst for CO2RR. These calculations are aimed to gain insight into the reaction mechanisms for the synthesis of ethylene, acetamide, and urea via coupling in the interfacial reaction micro-environment. Due to the sluggishness of CO2, the formation of a solvation electric layer by anions (F−, Cl−, Br−, and I−) and cations (Na+, Mg2+, K+, and Ca2+) leads to electron transfer towards the Cu surface. This process significantly accelerates the reduction of CO2. These results reveal that *CO intermediates play a pivotal role in N-integrated CO2RR. Remarkably, the Cu2-based N-doped carbon catalyst examined in this study has demonstrated the most potential for C–N coupling to date. Our findings reveal that through the process of a condensation reaction between *CO and NH2OH for urea synthesis, *NO3− is reduced to *NH3, and *CO2 to *CCO at dual Cu atom sites. This dual-site reduction facilitates the synthesis of acetamide through a nucleophilic reaction between NH3 and the ketene intermediate. Furthermore, we found that the I− and Mg2+ ions, influenced by pH, were highly effective for acetamide and ammonia synthesis, except when F− and Ca2+ were present. Furthermore, the mechanisms of C–N bond formation were investigated via ab-initio molecular dynamics simulations, and we found that adjusting the micro-environment can change the dominant side reaction, shifting from hydrogen production in acidic conditions to water reduction in alkaline ones. This study introduces a novel approach using ion-H2O cages to significantly enhance the efficiency of C–N coupling reactions.

Enhanced removal of lead ions from wastewaters by electrochemical adsorption using nitrogen-doped Ti3C2Tx MXene

As a two-dimensional material containing transition metal carbides and nitrides, MXene is often used in capacitive deionization for its excellent hydrophilic and pseudocapacitive properties. Nitrogen doping is widely used to improve the adsorption properties of certain materials. However, the effect of nitrogen doping on the electrochemical adsorption properties of MXene remains unclear. In this work, nitrogen-doped Ti3C2Tx MXene was synthesized using a simple hydrothermal method to achieve highly selective and efficient removal of Pb(II) at a constant cell voltage. The concentration of Pb(II) decreased from 4.95 to 0.02 mg L−1 in a 100 mg L−1 NaCl supporting electrolyte after electrosorption. The removal efficiency of Pb(II) reached 99.5%, whereas it was only 15.2% for Na+. The introduction of nitrogen functional groups increased the electrical conductivity and layer spacing of MXene, thereby improving the pseudocapacitive adsorption performance in the presence of Pb(II). The complexation function of the Ti-OH group on nitrogen-doped Ti3C2Tx surface increased and contributed to the selective adsorption of Pb(II). The removal efficiency of Pb(II) increased with increasing solution pH and cell voltage, reaching the maximum value at pH 5.0 and 1.5 V, respectively. The effect of supporting electrolyte type on the removal of Pb(II) was negligible. In addition, the removal efficiency for mixed heavy metal ion solutions, including Cu(II), Ni(II), and Pb(II), exceeded 79.0%. It exhibited the highest removal efficiency for Pb(II) at 97.9%. After five cycles of electrochemical adsorption–desorption, the nitrogen-doped Ti3C2Tx maintained a stable Pb(II) removal efficiency of 97.0%. This work provides a promising material for the electrochemical removal of low-concentration heavy metal ions from wastewaters.

Largely‐Tuned Effective Work‐Function of Al/Graphene/SiO2/Si Junction with Electric Dipole Layer at Al/Graphene Interface

AbstractThe effective work‐function of metal electrode is one of the major factors to determine the threshold voltage of metal/oxide/semiconductor junction. In this work, it is demonstrated experimentally that the effective work‐function of the Aluminum (Al) electrode in Al/SiO2/n‐Si junction increases significantly by ≈1.04 eV with the graphene interlayer inserted at Al/SiO2 interface. The device‐physical analysis of solving Poisson equation analytically is provided when the flat‐band voltage is applied to the junction, supporting that the large tuning of Al effective work‐function may originate from the electric dipole layer formed by the off‐centric distribution of electron orbitals between Al and graphene layer. Our work suggests the feasibility of constructing the dual‐metal gate CMOS circuitry just by using Al electrodes with area‐specific underlying graphene interlayer.

Simple, rapid and enzyme-free assay for potentiometric determination of L-cysteine based on meso-2,3-dimercaptosuccinic acid self-assembled gold electrode

As a sulfur containing α-amino acid in nature, L-cysteine plays a crucial role in a variety of metabolic pathways with many important physiological functions. However, it is still a great challenge to construct a simple and rapid approach for L-cysteine up to now. In this paper, a simple, rapid and enzyme-free method was developed for potentiometric determination of L-cysteine by using meso-2,3-dimercaptosuccinic acid self-assembled monolayer on gold electrode. The surface morphology and property of self-assembled membrane with and without L-cysteine combined were characterized by means of scanning electron microscopy, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry, respectively. The recognition mechanism may be attributed to formation of hydrogen bonds between meso-2,3-dimercaptosuccinic acid and the target molecule of L-cysteine, producing a double electric layer at the sensing interface, that the membrane potential decreases with increasing concentration of L-cysteine. The assay results showed that good linear potential response to L-cysteine in Tris-HCl buffer solution (pH=7.0) was obtained in a range of 1.0 × 10-8 to 1.0 × 10-3 mol/L, with a slope of −57.00 ± 0.63 mV/-pc (25 °C) and a detection limit of 7.9 × 10-9 mol/L. The electrode possessed fast response time (45 s), good reproducibility, and strong anti-interference performance. Moreover, the electrode can be well applied to the detection of L-cysteine in pig serums with a recovery rate of 94.3 ∼ 106.3%, indicating a promising application prospect.

Global insights on flood risk mitigation in arid regions using geomorphological and geophysical modeling from a local case study

This research provides a comprehensive examination of flood risk mitigation in Saudi Arabia, with a focus on Wadi Al-Laith. It highlights the critical importance of addressing flood risks in arid regions, given their profound impact on communities, infrastructure, and the economy. Analysis of morphometric parameters ((drainage density (Dd), stream frequency (Fs), drainage intensity (Di), and infiltration number (If)) reveals a complex hydrological landscape, indicating elevated flood risk. due to low drainage density, low stream frequency, high bifurcation ratio, and low infiltration number. Effective mitigation strategies are imperative to protect both communities and infrastructure in Wadi Al-Laith. Geophysical investigations, using specialized software, improve the quality of the dataset by addressing irregularities in field data. A multi-layer geoelectric model, derived from vertical electrical sounding (VES) and time domain electromagnetic (TDEM) surveys, provides precise information about the geoelectric strata parameters such as electrical resistivity, layer thicknesses, and depths in the study area. This identifies a well-saturated sedimentary layer and a cracked rocky layer containing water content. The second region, proposed for a new dam, scores significantly higher at 56% in suitability compared to the first region’s 44%. The study advocates for the construction of a supporting dam in the second region with a height between 230 and 280 m and 800 m in length. This new dam can play a crucial role in mitigating flash flood risks, considering various design parameters. This research contributes to flood risk management in Saudi Arabia by offering innovative dam site selection approaches. It provides insights for policymakers, researchers, and practitioners involved in flood risk reduction, water resource management, and sustainable development in arid regions globally.

Performance enhancements of HTS power cables by minimizing the electric field enhancements for electric transport applications

Abstract Design innovations to manage the electric field enhancements and successful use of cryogenic epoxy EP37 as electrical insulation for high temperature superconducting (HTS) cables for electric aircraft applications are reported. Detailed finite element analysis (FEA) of the electric field distribution shows that the highest electric field is at the interface of the ground and electrical insulation layers. The FEA led to the design, fabrication, and experimental characterization of four model cables with stress cones and a direct bond of the ground and insulation layers. Enhanced partial discharge inception voltage (PDIV) was achieved in the model cables by minimizing the electric field enhancements at the ground layer interface. Using a helium gas mixture with 4 mol% H2, with higher intrinsic dielectric strength than pure helium, further enhanced the PDIV. The results warrant further studies on long HTS cables with EP37 as electrical insulation with a direct bond between the insulation and ground layers.

Numerical Investigations into the Homogenization Effect of Nonlinear Composite Materials on the Pulsed Electric Field

Pulsed power equipment is often characterized by high energy density and field intensity. In the presence of strong electric field intensity, charge accumulation within insulators exacerbates electric field non-uniformity, leading to potential insulation breakdown, thereby posing a significant threat to the safe operation of pulsed power equipment. In this manuscript, we introduce nonlinear composite materials with field-dependent conductivity and permittivity to adaptively regulate the distribution of the pulsed electric field in insulation equipment. Finite-element modeling and analysis of the needle-plate electrodes and high-voltage bushing are carried out to comprehensively investigate the non-uniformity of the distribution of the electric field and the homogenization effect of various nonlinear materials in the presence of pulsed excitations of different timescales. Numerical results indicate that the involvement of nonlinear composite materials significantly improves the electric field distribution under pulse excitations. In addition, variations in the rising time of the pulses affect the maximum electric field intensity within the insulators considerably, but for pulses of nanosecond and microsecond scales, the tendencies are the opposite. Finally, via the simulations of the bushing, we illustrate that some measures proposed for improving the uniformity of the electric field under low frequencies, e.g., increasing the length of the electric field equalization layer and the distance of the underside of the electric field equalization layer from the grounding screen, are still effective for the homogenization of pulsed electric field.

Flexible boron nitride-based composite membrane with superhydrophobic/electrothermal synergistic response for enhanced passive anti-icing and active de-icing

Ice crystals and snow adhesion can affect the operation and reliability of machines in cold, snowy conditions, so anti-freeze systems are often installed in machines. Commonly used ice protection systems usually place electrothermal and a hydrophobic layer in one layer, or create a hydrophobic layer at top of the electrothermal layer. However, the hydrophobic layer ruptures and there is a risk of a short circuit when water comes into contact with the electrically heated layer. In this paper, a method of using boron nitride film to separate the functional layer is proposed to reduce the risk of short circuit in the electric heating layer. Finally, boron nitride film is successfully used as the intermediate layer to connect the superhydrophobic layer with the electric heating layer, which realizes the passive. The results show that the contact angle of the BN-based composite membrane can reach more than 160°. Under the heating power of 0.54 W/cm2, the BN-based composite membrane can reach the steady state temperature of 82.6 °C in 6 min, the deicing efficiency can reach 15.435 kg h−1 m−2, and the removal of 6 mm thick melting ice takes only 185 s. In addition, after 10 electric heating cycles, the BN-based composite membrane can still maintain a temperature of about 80 °C, indicating that it has good durability. This study is of great significance for practical ice control applications.

Impact of diatomit on the transport behavior of unmodified and carboxyl-modified nanoplastics in saturated porous media

Due to the extensive use of plastic products and unreasonable disposal, nanoplastics contamination has become one of the important environmental problems that mankind must face. The composition and structure of porous media can determine the complexity and diversity of the transport behavior of nanoplastics. In this study, the influence of diatomite (DIA) on the nanoplastics transport in porous media is investigated by column experiments combined with XDLVO interaction energy and transport model. Results suggest that the recovery rates of unmodified polystyrene nanoparticles (PSNPs) and carboxyl-modified polystyrene nanoparticles (PSNPs-COOH) in the porous media containing DIA decreases compared with that in the pure quartz sand (QS), and the BTCs showed a “blocking” pattern. The presence of DIA inhibits the transport of both PSNPs and PSNPs-COOH, but the inhibition is not significant. This may be because the presence of DIA provides more favorable deposition sites for PSNPs and PSNPs-COOH to some extent. However, since DIA itself carries a certain negative charge, this can only play a role in compressing the double electric layer for PSNPs and PSNPs-COOH with the same negative charge, and cannot destabilize them. The migration capacity of PSNPs and PSNPs-COOH is strongest in the DIA-QS porous media at pH = 7, and is weak at pH = 9 and pH = 5. The inhibition of migration at pH = 9 can be attributed to the dissolution of the DIA surface under alkaline conditions and the formation of pore and defect structures, which provide more deposition sites for PSNPs and PSNPs-COOH. The presence of humic acid (HA) leads to an increase in the mobility of PSNPs and PSNPs-COOH, and the mobility is enhanced with HA concentration. The mobility of PSNPs and PSNPs-COOH in DIA-QS decreases with ionic valence and ionic strength, and PSNPs-COOH is more significantly inhibited compared to PSNPs.

4D-STEM and Eels Analysis of Complex C-Based Sensor Architectures

Transforming high-carbon precursors into open-porous carbon foams and coatings via thermal processes is gaining attention as a sustainable method for various applications, including catalysis, energy utilization, and sensing [1]. In this research, we adopt a one-step laser patterning approach to selectively pyrolyze doctor-bladed ink coatings on flexible PET substrates, thereby producing highly porous, intricately designed CO2 sensor structures with a thickness of about 50 µm. Our ink formulation includes glucose as a pore-forming agent and adenine as a nitrogen source to enhance sensing capabilities. Laser processing in an oxygen-rich setting results in flexible, highly porous sensor heterostructures characterized by distinct areas enriched with nitrogen and oxygen functionalities. The laser intensity’s attenuation with depth leads to the development of a distinctly porous graphitic surface layer (serving as the electrical transducer layer) and a denser nitrogen-enriched lower sensor layer, linked by a narrow transitional region [2]. To understand the formation and functionality of these sensors, we conducted an in-depth TEM analysis of cross-sections of the complete device, prepared through ultramicrotomy cross-sectioning. STEM-EELS elemental distribution maps distinctly show the chemical composition differences between the upper and lower layers of the sensor. Principal component analysis was utilized to separate the complex sensor structures into their constituent crystalline and amorphous carbon and nitrogen-containing phases. 4D-STEM analysis exposed the arrangement of the crystalline graphitic phase and the orientation of graphite basal planes adjacent to the pores of the open-porous sensor. Analyzing these structural parameters is essential for understanding the electrical performance of the sensor, as depicted in Figure 1 [3]. Figure 1: A (top)) SEM micrograph of sensor embedded in epoxy, (bottom) depth-dependent thermal laser intensity attenuation; B (left)) HA ADF-STEM micrograph showing different sensor layers, (middle) STEM-EELS nitrogen distribution map, (right) PCA bond analysis, C) HRTEM images of sensor from transducer (top) and sensor (bottom) layers with SAED image of respective ROIs (inset); D) 4D-STEM analysis depicting misalignment angle between graphitic carbon basal plane normal relative to the pore surface normalReferences[1] M. Hepp, et al. npj Flexible Electronics 6, 1-9 (2022)[2] H. Wang, et al. Advanced Functional Materials 32, 2207406 (2022)[3] C. Ophus, et al. Microscopy and Microanalysis 28, 390-403 (2022) Acknowledgements: We acknowledge use of the DFG-funded Micro-and Nanoanalytics Facility (MNaF) at the University of Siegen (INST 221/131-1). Figure 1