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[Display omitted] • Designed a novel multifunctional CuTCPP/MXene/TiO 2 catalyst by crystal plane regulation and hydrogen bonding. • Developed a system for atmospheric CO 2 capture and in-situ conversion at the gas-solid interface. • There is no need to add any sacrificial agent and alkaline absorbent in the reaction system. • The catalyst demonstrated excellent CO 2 conversion rates, effectively producing CO and CH 4. Directly capturing atmospheric CO 2 and converting it into valuable fuel through photothermal synergy is an effective way to mitigate the greenhouse effect. This study developed a gas–solid interface photothermal catalytic system for atmospheric CO 2 reduction, utilizing the innovative photothermal catalyst (Cu porphyrin) CuTCPP/MXene/TiO 2. The catalyst demonstrated a photothermal catalytic performance of 124 μmol·g−1·h−1 for CO and 106 μmol·g−1·h−1 for CH 4 , significantly outperforming individual components. Density functional theory (DFT) results indicate that the enhanced catalytic performance is attributed to the internal electric field between the components, which significantly enhances carrier utilization. The introduction of CuTCPP reduces free energy of the photothermal catalytic reaction. Additionally, the local surface plasmon resonance (LSPR) effect and high-speed electron transfer properties of MXene further boost the catalytic reaction rate. This well-designed catalyst and catalytic system offer a simple method for capturing atmospheric CO 2 and converting it in-situ through photothermal catalysis. [ABSTRACT FROM AUTHOR]

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In-situ texturing hollow carbon host by gas–solid interface reaction with high pore volume and Fe single atoms doping ensures the excellent cycling performance of HCS-Fe/Se cathode due to its accelerating solid-phase redox kinetics. [Display omitted] • In-situ texturing hollow carbon sphere by one-step reaction between SiO 2 and PTFE. • H 2 SeO 3 is an ideal Se resource for homogeneous Se-based cathode. • DRT analyses verify the solid-phase conversion mechanism of HCS-Fe/Se. • Excellent performances realized due to electrocatalytic effect of Fe single atoms. Se-based cathodes have caught tremendous attention owing to their comparable volumetric capacity and better electronic conductivity to S cathodes. However, its low utilization ratio and sluggish redox kinetics due to the high reaction barrier of solid-phase transformation from Se to Li 2 Se limit its practical application. Herein, an in-situ texturing hollow carbon host by gas–solid interface reaction anchored with Fe single-atomic catalyst is designed and prepared for advanced Li-Se batteries. This Se host presents high pore volume of 1.49 cm3 g−1, Fe single atom content of 1.53 wt%, and its specific structure protects single-atomic catalyst from the destructive reaction environment, thus balancing catalytic activity and durability. After Se loading by reduction of H 2 SeO 3 , this homogenous Se-based cathode delivers a superior rate capacity of 431.3 mA h g−1 at 4C, and great discharge capacity of 301.8 mA h g−1 after 1000 cycles at 10C, with high Li-ion diffusion coefficient and capacitance-contributed ratio. The distribution of relaxation times analysis verifies solid-phase transformation mechanism of this cathode and density functional theory calculations confirm the adsorption and bidirectionally catalysis effect of Fe single-atomic catalyst. This work provides a new strategy to prepare high-efficient Se cathode associated with non-noble metal single atoms for high-performance Li-Se batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • CuTCPP was innovatively anchored on the surface of 2D anatase TiO 2 ultrathin nanosheets. • Taking low concentration CO 2 in ambient air as the research object, a photocatalytic integrated system for CO 2 capture and in-situ conversion was constructed. • CO 2 reduction conversion is achieved at the gas-solid interface. The practical application of photocatalytic reduction of CO 2 system becomes possible. • There is no need to add any sacrificial agent and alkaline absorbent in the reaction system. • This catalytic system can achieve stable, efficient and highly selective conversion. (CO 2 → CO). Directly capturing CO 2 in ambient air and converting it into value-added fuels using photocatalysis is a potentially valuable technology. In this study, Cu-porphyrin (tetrakis-carboxyphenyl porphyrin copper, CuTCPP) was innovatively anchored on the surface of TiO 2 (titanium dioxide) nanosheets to form an S-scheme heterojunction. Based on this, a photocatalytic reaction system for stably converting CO 2 in ambient air into value-added fuels at the gas–solid interface was constructed without addition of sacrificial agents and alkaline liquids. Under the illumination of visible light and sunlight, the evolution rate of CO is 56 μmol·g−1·h−1 and 73 μmol·g−1·h−1, respectively, with a potential CO 2 conversion rate of 35.8 % and 50.4 %. The enhanced of photocatalytic performance is attributed to the introduction of CuTCPP, which provides additional active sites, significantly improves capture capacity of CO 2 and the utilization of electrons. Additionally, the formation of S-scheme heterojunction expands the redox range and improves the separation efficiency of photo-generated charges. [ABSTRACT FROM AUTHOR]

The direct conversion of atmospheric CO2 into fuel via photocatalysis exhibits significant practical application value in advancing the carbon cycle. In this study, we established an electro-assisted photocatalytic system with dual compartments and interfaces, and coated Ag nanoparticles on the titanium nanotube arrays (TNTAs) by polydopamine modification. In the absence of sacrificial agent and alkali absorption liquid conditions, the stable, efficient and highly selective conversion of CO2 to CO at the gas-solid interface in ambient air was realized by photoelectric synergy. Specifically, with the assistance of potential, the CO formation rates reached 194.9 µmol h-1 m-2 and 103.9 µmol h-1 m-2 under ultraviolet and visible light irradiation, respectively; the corresponding CO2 conversion rates in ambient air were 30% and 16%, respectively. The excellent catalytic effect is mainly attributed to the formation of P-N heterojunction during the catalytic process and the surface plasmon resonance effect. Additionally, the introduction of solid agar electrolytes effectively inhibits the hydrogen evolution reaction and improves the electron utilization rate. This system promotes the development of photocatalytic technology for practical applications and provides new insights and support for the carbon cycle. [ABSTRACT FROM AUTHOR]

Charge accumulation usually happens on the surface of spacers under DC operation, which is susceptible to inducing surface flashover. In order to explore the surface charge accumulation mechanisms and the influences of dielectric conductivity, gas ion mobility, and temperature field on the surface charges, a time-varying charge density model at the gas–solid interface of spacers was established. The results of the simulation show that the discontinuity of the current density between the spacer bulk side and the gas ion flow is the fundamental reason for the charge accumulation on the spacer surface. Additionally, the value of current density fluxes at the interface continues to decrease with the change of the electric field, and the progress of charge transfer gradually stabilizes. Moreover, the dielectric conductivity directly affects the charge accumulation process, and there is a critical conductivity in which the effect of charge conduction in dielectrics counteracts that of gas-phase charge deposition, theoretically. When the conductivity is higher than the critical conductivity, the solid-side charge conduction is the main source of the surface charge accumulation, while the gas-phase charge deposition on the gas side plays a dominant role when the conductivity is lower than the critical conductivity. The charge accumulation is not significantly affected by gas ion mobility when the temperature is evenly distributed. However, under the temperature field with gradient distribution, the current density fluxes at the interface change, causing the polarity reverse of the accumulated charge. In the high-temperature region, the volume current density surges simultaneously with the conductivity, leading to a higher density of surface charge accumulation. Lastly, the design of spacers needs to keep the current densities on both sides of the interface as similar as possible in order to avoid excessive charge gathering in localized areas. [ABSTRACT FROM AUTHOR]

Industrial lignin, a by-product of pulping for papermaking fibers or of second-generation ethanol production, is primarily served as a low-grade combustible energy source. The fabrication of high-value-added functional materials with industrial lignin is still a challenge. Herein, a three-dimensional hierarchical lignin-derived porous carbon (HLPC) was prepared with lignosulfonate as the carbon source and MgCO3 as the template. The uniform mixing of precursor and template agent resulted in the construction of a three-dimensional hierarchical porous structure. HLPC presented excellent electromagnetic wave (EMW) absorption performance. With a low filler content of 7 wt%, HLPC showed a minimum reflection loss (RL) value of −41.8 dB (1.7 mm, 13.8 GHz), and a maximum effective absorption bandwidth (EAB) of 4.53 GHz (1.6 mm). In addition, the enhancement mechanism of HLPC for EMW absorption was also explored through comparing the morphology and electromagnetic parameters of lignin-derived carbon (LC) and lignin-derived porous carbon (LPC). The three-dimensional hierarchical porous structure endowed the carbon with a high pore volume, resulting in an abundant gas–solid interface between air and carbon for interfacial polarization. This structure also provided conductive networks for conduction loss. This work offers a strategy to synthesize biomass-based carbon for high-performance EMW absorption. [ABSTRACT FROM AUTHOR]

In this work, the impedance spectroscopy (IS) technique was used to aid in understanding the reaction mechanism of the CO oxidation reaction using the Pr2Zr2−xFexO7±δ (x = 0 and 0.10) mixed oxide as a heterogeneous catalyst. The catalytic reaction occurred in the same temperature range where there was a decrease in the overall resistivity of the materials. Moreover, it has been observed that within the temperature range where the catalytic process takes place, there is a variation in the A and n parameters of the power law dispersion. Combining IS with catalytic reactions offers a robust approach to enhance the understanding of the mechanisms involved in the CO oxidation reaction. It enables precise analysis of the changes that take place at the solid–gas interface, particularly the generation of reactive oxygen species. Furthermore, it allows examining the relationship between the presence of oxygen vacancies and defects, which directly impact the catalytic process. [ABSTRACT FROM AUTHOR]

This review examines the significance of the zeta adsorption model in physics and its integration with statistical mechanics within the field of interface adsorption. Through a comprehensive analysis of existing research, this study presents the collective findings and insights derived from the reviewed literature. The zeta adsorption model, proposed by Ward, has gained recognition for its seamless extension into the thermal disequilibrium region without encountering singularities. By incorporating principles from quantum mechanics and statistical thermodynamics, this model offers fresh perspectives on the adsorption of gas molecules on solid surfaces. Notably, it demonstrates enhanced accuracy in describing the adsorption performance of mesoporous materials and nanomaterial surfaces, surpassing the limitations of traditional models such as the BET isotherm. Additionally, this review explores the behavior of cluster formation under varying temperature and pressure conditions. It highlights the correlation between increasing pressure ratios and the decreased availability of empty adsorption sites, resulting in the formation of larger clusters within the adsorbate. Ultimately, this process leads to a transition from adsorption to condensation, where the liquid phase wets the solid surface. Moreover, the zeta adsorption model provides a solid theoretical foundation for understanding crucial aspects of gas-solid interface adsorption. It enables the determination of the distribution of adsorbate clusters on gas-solid interfaces, facilitates the identification of wetting pressure ratios during phase transitions, and allows for the calculation of solid surface tension under conditions of zero adsorption. Noteworthy parameters such as the bonding strength (β) between the solid surface and adsorbed atoms significantly influence the overall strength of the solid-fluid interaction. Furthermore, the phenomenon of surface subcooling, which necessitates sufficient energy for the transformation from adsorbed vapor to condensate liquid, plays a pivotal role in studying interface phase transitions. Additionally, this review investigates the thermodynamic stability of the adsorbate through an analysis of molar latent heat. It reveals that beyond a critical adsorbate coverage, the formation of critical-sized clusters and the ensuing interactions among these components render the adsorbate unstable. This instability prompts a transition from the interface to a liquid phase, followed by subsequent adsorption onto the surface. In summary, this literature review highlights the significant contributions of the zeta adsorption model to the field of physics, particularly in the context of interface adsorption. It serves as a valuable tool for studying various materials and cluster formation, thanks to its seamless extension into the thermal disequilibrium region and its incorporation of principles from quantum mechanics and statistical thermodynamics. By presenting a synthesis of existing research, this review sheds light on the advantages of the zeta adsorption model and paves the way for further investigations into gas-solid interface adsorption phenomena. [ABSTRACT FROM AUTHOR]

Context: SF6 gas has a strong greenhouse effect, and how to treat SF6 in an environmentally friendly way has been a hot topic of current research. In this paper, the adsorption behavior of SF6 on the surface of Pd-doped hydroxyl-terminated modified Ti3C2Tx (i.e., Ti3C2(OH)2) was investigated based on the density functional theory using two-dimensional MXene as the catalyst. The structures of different Pd-doped Ti3C2(OH)2 were analyzed and the most structurally stable doped structures were selected as the basis for subsequent calculations. A large number of adsorption configurations were constructed and geometrically optimized, and the adsorption energy, charge transfer, differential charge density, and density of states of the systems were calculated in order to analyze the gas–solid interactions and find the surface active sites; compared with the adsorption performance of undoped Ti3C2(OH)2 on SF6, it was found that Pd doping played a less inhibitory role in the adsorption of SF6 on the Ti3C2(OH)2 surface. The results of this study can provide theoretical support for the use of Pd-doped Ti3C2(OH)2 as a catalyst for the degradation of SF6. Methods: In this paper, simulations of SF6 adsorption on Ti3C2Tx surfaces are based on density functional theory and are carried out in the Dmol3 module of Material Studio. To better describe the non-uniform electron density of the actual system, the PBE functional in the generalized gradient approximation (GGA) was chosen for the optimization of the structure of the gas–solid interface system and the calculation of the relevant electronic properties, combined with the Grimme dispersion correction in the DFT-D dispersion correction for the electron exchange correlation term. Because both Pd and Ti are transition metal elements, the mode-conserving pseudopotential DNP basis set containing relativistic effects was chosen for the electronic wave function expansion. In this paper, an all-electron model is used for the inner core treatment of gas molecules and a density generalized semi-nuclear pseudopotential DSSP is used for the solid surface treatment. [ABSTRACT FROM AUTHOR]

A low concentration of Te4+ doping is found to be capable of endowing the lead-free Cs2SnCl6 perovskites with excellent photoluminescence quantum yield (PLQY), while further increasing Te4+ concentration leads to PLQY deterioration. The mechanism behind the improved PLQY is intensively studied and reported elsewhere. However, little work is conducted to understand the decreased PLQY at high doping levels and to explore its implications for non-PL-related applications. Here, it is demonstrated that the Te4+-incorporated Cs2SnCl6 can be promising candidate for efficient CO2 photocatalysis. An optimum photocatalytic performance is achieved when Te4+ concentration reaches as high as 50%, at which point significant PL quenching has occurred. Through a detailed spectral characterization, such concentration-dependent functionality is attributed to systematic changes in both electronic and local crystal structure, which allow a robust regulation of excitation energy relaxation channels. These findings expand the scope of available photocatalysts for CO2 reduction and also inform synthetic planning for the preparation of multifunctional Pb-free metal halide perovskites. [ABSTRACT FROM AUTHOR]

We propose an innovative and scalable NH 4 Cl-assisted gas–solid interface reaction treatment technique, where NH 4 Cl thermally decomposes to HCl and NH 3 gas at 350 °C. In situ construction of oxygen vacancies and spinel phase structures on the surface of LMOs by reaction with HCl and NH 3 gas. The synergistic effect of oxygen vacancies and surface spinel phases can not only effectively enhance the redox properties of oxygen ions and inhibit irreversible oxygen release, but also effectively mitigate side reactions at the electrode/electrolyte interface, stabilize the layered structure and enhance the Li+ diffusion rate. [Display omitted] • An innovative and scalable NH 4 Cl-assisted gas–solid interface reaction treatment technique is proposed for the simultaneous construction of oxygen vacancies and surface spinel phases on LMOs. • The surface spinel phase structure not only improves the stability and reduces the side effects of the interface, but also effectively improves the Li+ diffusion kinetics. • The pre-constructed oxygen vacancy increases the state density of the O-2p orbital near the Fermi level and increases the energy of oxygen vacancy formation, thus enhancing the redox of oxygen ions and reducing the irreversible release of O 2. Li-rich Mn-based oxide cathodes (LMOs) are regarded as one of the most prospective high energy density cathodes due to the reversible anion redox reaction, which gives them a very high capacity. However, LMOs materials usually have problems like low initial coulombic efficiency (ICE) and poor cycling performance during cycling, which are associated with irreversible surface O 2 release and unfavourable electrode/electrolyte interface side reactions. Herein, an innovative and scalable NH 4 Cl-assisted gas–solid interfacial reaction treatment technique is employed to construct oxygen vacancies and spinel/layered heterostructures simultaneously on the surface of LMOs. The synergistic effect of the oxygen vacancy and the surface spinel phase can not only effectively enhance the redox properties of the oxygen anion and inhibit irreversible oxygen release, but also effectively mitigate the side reactions at the electrode/electrolyte interface, inhibit the formation of CEI films and stabilize the layered structure. The electrochemical performance of the treated NC-10 sample improved significantly, showing an increase in ICE from 77.4 % to 94.3 % and excellent rate capability and cycling stability, with a capacity retention of 77.9 % after 400 cycles at 1 C. This oxygen vacancy and spinel phase integration strategy offers an exciting prospect and avenue for improving the integrated electrochemical performance of LMOs. [ABSTRACT FROM AUTHOR]

Recent study has found excellent bulk and surface insulation property of Si 3 N 4 ceramic which make it potential to serve as key insulation component in various energy transmission apparatus. Charge accumulation at gas-solid interface is a critical insulation property but few relevant study on Si 3 N 4 can be found. This contribution has investigated the surface charge property of Si 3 N 4 ceramic compared to traditional insulation polymer under different electrical-thermal stress. Through its comparison with the electric field distribution, the main source of the surface charge accumulation is analyzed, indicating that the superior surface charge suppression performance of Si 3 N 4 lies on its low carrier density and conduction barrier, which considerably prevent charge injection and suppress the normal electric field which drives the charge to the gas-solid interface. The proposed mechanism is also validated by the characterization on conducting and space charge property for Si 3 N 4 as well as dynamic simulation on surface charge accumulation. [ABSTRACT FROM AUTHOR]

A facile method for green and selective synthesis of all-crystalline graphdiyne based iso-atomic catalysts (CuEr-GDY) for. CuEr-GDY exhibited transformative properties on artificial photosynthesis of 97.6% selectivity and highest CO yield (181.04 μmol g−1 h−1). Such excellent properties originated from strong interactions between graphdiyne and heterometallic atoms, and between the metal heteroatoms, resulting in incomplete charge transfer to produce high activity. [Display omitted] Herein we report a bimetal atomic catalyst that features atomically dispersed Cu and Er atoms anchored on all crystalline graphdiyne (CuEr-GDY) for efficient artificial photosynthesis converting CO 2 into sustainable fuel at the gas–solid interfaces with water as reducing medium instead of organic reagent. The CuEr-GDY can promote the efficient separation of photogenerated electron-hole pairs to drive water oxidation and CO 2 activation/reduction, together with Cu/Er promoted CO 2 /H 2 O adsorption and CO desorption. This result indicates that bimetallic atoms on the high-crystalline GDY surface have high activity. This heteroatomic catalyst of CuEr-GDY demonstrates high catalytic activity with the reaction selectivity up to 97.6%, and the competitive hydrogen evolution reaction is almost completely suppressed. The CO 2 conversion achieves the CO yield of 181.04 μmol g−1 h−1 under ambient conditions. [ABSTRACT FROM AUTHOR]

Covalent organic framework nanosheets (COF nanosheets) are two-dimensional crystalline porous polymers with in-plane covalent bonds and out-of-plane Van der Waals forces. Owing to the customizable structure, chemical modification, and ultra-high porosity, COF nanosheets show many fascinating properties unique to traditional two-dimensional materials, and have shown potential applications in gas separation, sensors, electronic, and optoelectronic devices. This minireview aims to illustrate recent progress on two-dimensional covalent organic framework nanosheets, from two aspects of on-surface synthesis and potential applications. We first review the synthesis of COF nanosheets at the gas–solid interface. On-surface synthesis under ultrahigh vacuum and on-surface synthesis under vapor are highlighted. In addition, we also review the liquid–solid interface synthesis of COF nanosheets at various substrates, i.e., both crystalline and amorphous substrates. Beyond the synthesis, we highlight state-of-the-art applications of the COF nanosheets, particularly in charge transport, chemical sensors, and gas separation. [ABSTRACT FROM AUTHOR]

The present paper investigates the stabilization of Mg-3Ca alloy and Mg-3Ca/SiC/5p composite foams with and without the addition of 0.12 wt.% beryllium. In Mg-3Ca alloy foam, Be addition has shown a significant improvement in the expansion and pore structure. Whereas, in case of Mg-3Ca/SiC/5p composite foams, the SiC particles stabilized the foam effectively, while Be addition does not show any distinguishable improvement in the foam structure. The formation of BeO and the dense coverage of SiC particles in the gas–solid interface of Mg-3Ca and Mg-3Ca/SiC/5p composite foams, respectively, are the reasons for the foam stabilization. Mg-3Ca/SiC/5p composite foam exhibited lowest foam density of 0.10 g/cm3. The quasi-static compression test shows that Mg-3Ca-0.12Be/SiC/5p composite foam containing Be exhibited lower foam density and higher normalized compressive strength. The energy absorption capacity per unit foam density in Be containing foams was also higher. [ABSTRACT FROM AUTHOR]

Contact electrification exists everywhere and between every phase of matter. However, its mechanism still remains to be studied. The recent triboelectric nanogenerator serves as a probe and provides some new clues about the mechanism present in solid–solid, solid–liquid, and liquid–liquid contact electrification. The gas–solid model still remains to be exploited. Here, we investigated the contact electrification between gases and solids based on the single-electrode triboelectric nanogenerator. Our work shows that the amount of transferred charges between gas and solid particles increases with surface area, movement distance, and initial charges of particle increase. Furthermore, we find that the initial charges on the particle surface can attract more polar molecules and enhance gas collisions. Since ions in gas–solid contact are rare, we speculate that gas–solid contact electrification is mainly based on electron transfer. Further, we propose a theoretical model of gas–solid contact electrification involving the gas collision model and initial charges of the particle. Our study may have great significance to the gas–solid interface chemistry. [ABSTRACT FROM AUTHOR]

Dilute and dense conveying systems through pipelines are a common practice in our everyday life. It is used in many industries to convey a mixture of gas and solids from one location to another through pipes. Gas-solid transport is desirable in some industries but unwanted in others. Depending on the density, size, and shape, these solid particles may result in erosion and subsequent damage to piping and other equipment. Understanding the gas-solid two-phase flow dynamics can help develop efficient and cost-effective pipe transport systems, thereby mitigating the problems associated with the gas-solid two-phase flow. Models for estimating volumetric flow rates and other gas-solid two-phase flow properties are scarce as most are very complex, expensive, and unavailable proprietary commercial software. This study, therefore, developed a simple model using the general energy balance equation and relevant mixing theories for estimating the volumetric flow rate of natural gas-solid two-phase flow in horizontal pipes. The results from the model showed that the gas-solid flow rate is a function of pipe diameter, pressure drop, pipe length, solid volumetric concentration, solid-to-gas density ratio, and solid-to-gas friction factor ratio. [ABSTRACT FROM AUTHOR]

The solid-to-gas phase transition of potassium during biomass combustion significantly impacts ash-related issues in bioenergy systems, affecting operational efficiency and equipment longevity. However, the specific mechanisms and kinetics of this transition process remain inadequately understood. This work investigates the time-resolved transition of solid-phase potassium to the gas phase during the combustion of rice husk and wheat straw pellets, combining experimental measurements with theoretical modeling. Tunable diode laser absorption spectroscopy (TDLAS) was employed to measure atomic potassium concentrations 15 mm above burning pellets tray, where gas-phase equilibrium is approached. Key combustion characteristics including thermogravimetric profiles, spectral radiation, and temperature were simultaneously monitored. A novel multi-step model was developed to describe the transition of different forms of solid-phase potassium (organic, exchangeable, and inorganic) to the gas phase. This model integrates TDLAS measurements, observed combustion characteristics, and biomass physicochemical properties. Thermodynamic equilibrium calculations were used to estimate the atomic potassium fraction from total gaseous potassium. The results showed that the solid-to-gas phase transition of organic potassium synchronizes with volatiles release. In contrast, the maximum emission rates of inorganic and exchangeable potassium occurred at the onset of char combustion. The developed model agrees well with the online detection experiments and were further validated by offline ICP analysis of residual ash. While not directly simulating gas-solid interface reactions near the particle surface, this work lays groundwork for future multi-scale modeling of particle-laden flows and reactor-scale phenomena in biomass combustion systems. [ABSTRACT FROM AUTHOR]

Aerogels have been attracting wide attentions in flexible/wearable electronics because of their light weight, excellent flexibility, and electrical conductivity. However, multifunctional aerogel‐based flexible/wearable electronics for human physiological/motion monitoring, and energy harvest/supply for mobile electronics, have been seldom reported yet. In this study, a kind of hybrid aerogel (GO/CNT HA) based on graphene oxide (GO) and carboxylated multiwalled carbon nanotubes (CMWCNTs) is prepared which can not only used as piezoresistive sensors for human motion and physiological signal detections, but also as high performance triboelectric nanogenerator (TENG) coupled with both solid–solid and gas–solid contact electrifications (CE). The repeatedly loading–unloading tests with 20 000 cycles exhibit its high and ultrastable piezoresistive sensor performances. Moreover, when the obtained aerogel is used as the electrode of a TENG, high electric output performance is produced due to the synergistic effect of solid–solid, and gas–solid interface CEs (3D electrification: solid–solid interface CE between the two solid electrification layers; gas–solid interface CE between the inner surface of GO/CNT HA and the air filled in the aerogel pores). This kind of aerogel promises good applications for human physiological/motion monitoring and energy harvest/supply in flexible/wearable electronics such as piezoresistive sensors and flexible TENG. [ABSTRACT FROM AUTHOR]

With the development of internet of things and artificial intelligence electronics, metal oxide semiconductor (MOS)‐based sensing materials have attracted increasing attention from both fundamental research and practical applications. MOS materials possess intrinsic physicochemical properties, tunable compositions, and electronic structure, and are particularly suitable for integration and miniaturization in developing chemiresistive gas sensors. During sensing processes, the dynamic gas–solid interface interactions play crucial roles in improving sensors' performance, and most studies emphasize the gas–MOS chemical reactions. Herein, from a new view angle focusing more on physical gas–solid interactions during gas sensing, basic theory overview and latest progress for the dynamic process of gas molecules including adsorption, desorption, and diffusion, are systematically summarized and elucidated. The unique electronic sensing mechanisms are also discussed from various aspects including molecular interaction models, gas diffusion mechanism, and interfacial reaction behaviors, where structure–activity relationship and diffusion behavior are overviewed in detail. Especially, the surface adsorption–desorption dynamics are discussed and evaluated, and their potential effects on sensing performance are elucidated from the gas–solid interfacial regulation perspective. Finally, the prospect for further research directions in improving gas dynamic processes in MOS gas sensors is discussed, aiming to supplement the approaches for the development of high‐performance MOS gas sensors. [ABSTRACT FROM AUTHOR]

Much attention has been paid to developing effective visible light catalytic technologies for VOC oxidation without requiring extra energy. In this paper, a series of sponge-based catalysts with rich three-dimensional porosity are synthesized by combining MnOx and graphitic carbon nitride (GCN) with commercial melamine sponges (MS) coated with polydopamine (PDA), demonstrating excellent photothermal catalytic performance for formaldehyde (HCHO). The three-dimensional porous framework of MS can provide a good surface for material modification and a reliable interface for gas-solid interaction. The grown layer of PDA framework not only increases the near-infrared wavelength absorption for improving the light-to-heat conversion of catalysts, but also brings excellent adhesion for the subsequent addition of MnOX and GCN. The efficient formaldehyde oxidation is attributed to the sufficient oxygen vacancies generated by co-loaded MnOX and GCN, which is conducive to the activation of more O2− in the oxidation process. As the surface temperature of catalyst rapidly increases to its maximum value at ca. 115 °C under visible light irradiation, the HCHO concentration drops from 160 ppm to 46 ppm within 20 min. The reaction mechanism is certified as a classical Mars-van Krevelen mechanism based on the photo-induced thermal catalysis process. [ABSTRACT FROM AUTHOR]

In this article, a joint measurement of dielectric polarization, depolarization, and potential recovery is carried out to investigate the instantaneous and relaxation polarization characteristics of epoxy resin in high magnetic field. The dielectric polarization of epoxy resin is converted to a combination of weakened instantaneous polarization and the relaxation polarization with reduced amplitude and increased speed. Changes in dielectric polarization processes leads to the decrease of relative permittivity. Furthermore, partial discharge (PD) of internal defects is harder to be initiated in high magnetic field. However, the discharge frequency is increased and the phase distribution becomes wider in the case of ac. In the case of dc, discharge lasts for longer time in high magnetic field. The experimental results are caused by the coupling effects of high-speed polarization and abnormal charge accumulation at the gas-solid interface due to the effects of Lorentz force on charges generated by PD. [ABSTRACT FROM AUTHOR]

A deep understanding of surface catalysis recombination characteristics is significant for accurately predicting the aeroheating between hypersonic non-equilibrium flow and thermal protection materials, while a de-coupling sensitivity analysis of various influential factors is still lacking. A gas–solid interface (GSI) model with a hyperthermal flux boundary was established to investigate the surface catalysis recombination mechanisms on nanoscale silica surfaces. Using the reactive molecular dynamics (RMD) simulation method, the effects of solid surface temperature, gas incident angle, and translational energy on the silica surface catalysis recombination were qualified under hyperthermal atomic oxygen (AO), atomic nitrogen (AN), and various AN/AO gas mixtures' influence. It can be found that, though the Eley–Rideal (E–R) recombination mechanism plays a dominant role over the Langmuir–Hinshelwood (L–H) mechanism for all the sensitivity analyses, a non-linear increasing pattern of AO recombination coefficient γO2 with the increase in incident angle θin and translational energy Ek is observed. Compared with the surface catalysis under hyperthermal AO impact, the AN surface adsorption fraction shows an inverse trend with the increase in surface temperature, which suggests the potential inadequacy of the traditional proportional relationship assumptions between the surface adsorption concentration and the surface catalysis recombination coefficient for other species' impact instead of AOs. For the incoming bi-component AO/AN gas mixtures, the corresponding surface catalysis coefficient is not the simple superposition of the effects of individual gases but is affected by both the intramolecular bond energies (e.g., O2, N2) and intermolecular energies (e.g., Si/N, Si/O). [ABSTRACT FROM AUTHOR]

Abstract\nImpact statementFor olfactory sensors, clear differentiation of complex odour samples requires diverse information. To obtain such information, hardware modifications, such as introducing additional channels with different physical/chemical properties, are usually needed. In this study, we present a new approach to augment the sensing signals of an olfactory sensor by modulating the flow rate of the carrier gas. The headspace vapour of complex odours is measured using a sensing system of nanomechanical sensor (Membrane-type Surface stress Sensor, MSS). The resulting data set is quantitatively evaluated using the Davies-Boulding index (DBI) of principal component analysis (PCA). The increasing number of sensing signals obtained at different gas flow rates leads to a decrease in the DBI, achieving better cluster separation between different odours. Such gas flow effects can be attributed to several factors, including the sample evaporation and the equilibrium of the gas-liquid and gas-solid interfaces. Proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF-MS) experiments reveal that the compositions of odour samples vary with the different gas flow rates. It is demonstrated that a simple technique of modulating gas flow rates can significantly improve the differentiation performance of complex odours, providing additional degree of freedom in olfactory sensing.We present a novel system-based approach to augmenting olfactory sensor signal output by carrier gas flow rates modulation, enhancing odour differentiation performance through experimental, statistical, and analytical validation. [ABSTRACT FROM AUTHOR]

• Micromechanical modelling of the thermal conductivity of gas-solid mixture medium with imperfect interface. • Eshelby's ellipsoidal inhomogeneity problem. • Green's function technique and integral equation, • Ellipsoidal harmonics method for the thermal conduction inside gas-solid mixture medium. • Analytical expressions of local mean intensity and effective thermal conductivity. The present paper deals with the micromechanical modeling of the thermal conductivity of two-phase gas-solid mixtures with ellipsoidal inhomogeneities. In some structural morphologies, when the characteristic size of the gas-filled inhomogeneity is comparable to the mean path of the gas molecule, the classical heat conduction theory is no longer applicable to the regions very close to the solid interfaces. The present work assumes a sliding flow regime and a Knudsen number such that: 0 < K n ≪ 1. K n = λ / l where λ is the mean path of the gas molecule and l is the size of the inhomogeneity. In this situation, the thermal behavior of the gas can be described by the classical thermal conductivity with modified boundary conditions, considering discontinuities in the local heat flux and temperature fields across gas-solid interfaces. Within this framework, the solution of two problems involving a gaseous ellipsoidal inhomogeneity immersed in a solid matrix, and conversely a solid ellipsoidal inhomogeneity suspended in a gas, is developed. For the first problem, the proposed micromechanical approach is based on the use of Green's function technique and the integral equation established in the general case of anisotropic thermal conductivity per phase. For the second issue, the solution is obtained directly by solving the Fourier equation describing heat transfer in the heterogeneous medium. Then, the Mori–Tanaka (MT) method and the Differential (DS) Scheme are employed to express the effective thermal conductivity of the gas-solid mixture media. [ABSTRACT FROM AUTHOR]

The micro-SiC/Epoxy composite coating has huge potential for application in the insulator of high voltage direct current (HVDC) gas insulated switchgear (GIS) since it can effectively suppress charge accumulation at gas–solid interface and adaptively regulate resistive electric field distribution. However, achieving stable and fruitful properties often requires high filler concentrations, which can compromise processability and long-term stability. Thus, a new method is proposed for preparing SiC/Epoxy composite coatings based on in-situ electric-field-induced assist (EFIA). The alignment process of SiC induced by the in-situ electric field, the effects of in-situ field on the physical and chemical properties of cured composites were studied. Even at concentrations far below the percolation threshold, the alignment of SiC particles along the in-situ electric field direction can induce significant non-linear conductive properties along that specific direction in the composite. Furthermore, the EFIA-coating leads to a 59.43% reduction in surface charge accumulation, more than a 50% decrease in charge dissipation time, and a 17.3% increase in surface flashover voltage. The coating discussed in this paper will be helpful in insulation design of DC components. [Display omitted] • Develop an in-situ electric field-assisted method for preparing epoxy-matrix composite coatings. • Low concentration composites with aligned additives can exhibit significant non-linear conductive properties. • Epoxy-matrix SiC composite coatings prepared based on in-situ electric field assists can effectively regulate surface charge and enhance surface flashover voltage. [ABSTRACT FROM AUTHOR]

Ultra-lightweight foamed cement (ULFC) exhibits super-high porosity and excellent thermal-insulation capabilities. However, the thermodynamic instability and high water-absorptivity of ULFC with high-volume fly ash have restricted its large-scale application. Superhydrophobic technology can significantly improve the substrates' hydrophobicity, among which the nanocoating is a popular option but the water-repellent layer may be easily destroyed due to the mechanical damage. Therefore, the intrinsic superhydrophobization becomes a promising alternative to the coating scheme. Here, the internal superhydrophobic ULFC was formulated through introducing the ultrasonic-assisted siloxane-encapsulated Pickering emulsions, in which two Pickering structures containing n-dodecyltrimethoxysilane were stabilized by hydrophobic SiO 2 and C–S–H nanoparticles, respectively. Compared with the SiO 2 nanoparticles-stabilized dispersion, the droplets of C–S–H nanoparticles-stabilized Pickering emulsion were more stable and controlled-release in cement hydration environment. As such, the incorporation of the latter showed no negative impact on the setting times and static yield stress of the interstitial matrix, optimizing the homogeneity, mechanical strength and heat conductivity of ULFC. The combination of nanoscale foam stabilizer and Pickering emulsions could form the hierarchical waterproof structure with low surface free energy at the gas-solid interfaces, and the multiscale siloxane-grafted intertwined hydration products were responsible for the inner superhydrophobicity of ULFC. Therefore, under the water vapor-saturated environment, the water absorption of superhydrophobic samples showed only a slight increase as a function of time and the ULFC was still hydrophobic with a reduction of apparent water contact angle from 154.6° to 137.8°. From energy consumption analysis, the all-dimensional superhydrophobic ULFC had a potential application in heat-insulation building. [ABSTRACT FROM AUTHOR]

It is a challenge to study the nucleation of cavitation bubbles, which critically depends on nanoscale morphological features. Our recent advances in synthesizing colloidal negative-curvature nanoparticles (NGC-NPs) offer a rare opportunity, in comparison to the conventional studies of bulk substrates, where it is difficult to obtain consistent and well-defined surface features. In order to quantitatively assess their effects, we exploit the radical-induced color change of [Fe(SCN) 6 ]3−, which turned out to be a more convenient method than the bending of AgNWs and the fluorescence-based methods. We show that the NGC-NPs outperform positive-curvature nanoparticles (PSC-NPs) and homogeneous nucleation, in terms of promoting cavitation. The NGC-NPs provide a higher percentage of gas–solid interface, and thus reduces the activation barrier during the critical stage of bubble nucleation. This leads a higher probability of cavitation and transforms more energy from ultrasonication to radical formation and shockwaves. [ABSTRACT FROM AUTHOR]

The gas–solid interface of high-voltage insulating equipment is a weaker part of insulating equipment insulation, and preventing the occurrence of discharge along the surface of insulating equipment is a critical problem for high-voltage insulation. This article investigates the discharge characteristics and charge movement characteristics of insulating media under an airflow environment. The surface discharge characteristics of the insulating medium in the airflow environment were obtained by using a high-velocity airflow test platform, and the surface discharge voltage characteristics, discharge path characteristics, and force conditions of the discharge process were analyzed. The surface charge motion characteristics of the insulating medium in the high-velocity airflow environment were also tested, and the distribution characteristics, dissipation characteristics and conduction mechanism of the surface charge of the insulating medium in the high-velocity airflow environment were revealed. The research results showed that: the discharge voltage along the insulating medium surface gradually increases with the increasing velocity of airflow; the discharge path along the surface of the insulating medium gradually shifts backward under the action of airflow; under the action of airflow, the charge on the insulating medium surface is blown away, thus reducing the charge concentration on the insulating medium surface; the trap level center of the insulating medium gradually decreases under the action of airflow, which provides the conditions for the charge blowing effect on the insulating medium surface. This investigation supplies the theory support for the protection of insulation equipment in an airflow environment and technical guidance for the insulation design of insulating equipment in an airflow environment to ensure the secure and steady running of insulating equipment in high-speed trains and high-voltage transmission lines. [ABSTRACT FROM AUTHOR]

The present review concerns thin film field effect transistor (TFT)-based gas sensors with special emphasis on material synthesis, electrical characterizations and sensing properties. A comparative analysis of TFT sensors with that of resistive and capacitive sensors is carried out. Comparison reveals that resistive and capacitive sensors have higher sensitivity, whereas TFT sensors offer improved selectivity and higher reliability. This is attributed to gate voltage-induced carrier transport through the sensing channel that reduces the need for higher operating temperature unlike in the case of resistive and capacitive devices. The gas-sensing mechanism is co-related considering adsorption-desorption isotherms and work function modulation at the gas-solid interface. Type of electrode and density of surface states play a major role for sensitivity and reliability enhancement. Factors influencing stability, repeatability and selectivity improvement are also discussed. [ABSTRACT FROM AUTHOR]

Poor contact is one of the main causes of the internal fault of SF6 gas insulated equipment. Taking the most common over-thermal decomposition process of SF6 caused by poor silver-plated copper contacts as an example, this article combines with density functional theory (DFT) and establishes the gas–solid contact interface adsorption model of SF6 and its main decomposition characteristic products (SO2F2, SO2, SOF2, HF, and H2S) with solid silver. Adsorption energy, charge transfer, and density of electronic state were used to analyze the reaction activity of SF6 and its main decomposition products with the Ag surface. It is found that SF6 and SO2 are chemically adsorbed on the Ag surface, and the reaction activity is relatively strong. When chemical adsorption occurs, SF6 bonds with the metal surface by the 2p orbitals of F atoms, and SO2 is bonded to the metal surface by the 2p orbitals of O atoms. There is also a strong reaction trend between HF and Ag (1 1 1), while SO2F2, SOF2, and H2S only physically absorbed with the Ag (1 1 1) surface. This indicates that under the local overheating failure caused by metal contacts, SF6 will first undergo chemical adsorption in the SF6/Ag (1 1 1) system and then undergo a decomposition reaction near the metal surface rather than in free space. The participation of Ag reduces the difficulty of the decomposition reaction to some extent. The results lay a foundation for finally revealing the interfacial reaction process of SF6-Ag. [ABSTRACT FROM AUTHOR]

Photoelectrochemical devices integrate the processes of light absorption, charge separation, and catalysis for chemical synthesis. The monolithic design is interesting for space applications, where weight and volume constraints predominate. Hindered gas bubble desorption and the lack of macroconvection processes in reduced gravitation, however, limit its application in space. Physico‐chemical modifications of the electrode surface are required to induce gas bubble desorption and ensure continuous device operation. A detailed investigation of the electrocatalyst nanostructure design for light‐assisted hydrogen production in microgravity environment is described. p‐InP coated with a rhodium (Rh) electrocatalyst layer fabricated by shadow nanosphere lithography is used as a model device. Rh is deposited via physical vapor deposition (PVD) or photoelectrodeposition through a mask of polystyrene (PS) particles. It is observed that the PS sphere size and electrocatalyst deposition technique alter the electrode surface wettability significantly, controlling hydrogen gas bubble detachment and photocurrent–voltage characteristics. The highest, most stable current density of 37.8 mA cm−2 is achieved by depositing Rh via PVD through 784 nm sized PS particles. The increased hydrophilicity of the photoelectrode results in small gas bubble contact angles and weak frictional forces at the solid–gas interface which cause enhanced gas bubble detachment and enhanced device efficiency. [ABSTRACT FROM AUTHOR]

Coal is the dominant energy resource in China. With the Chinese policy of committing to reducing peak carbon dioxide emissions and achieving carbon neutrality, coal separation has recently become a hot topic, especially the fluidized separation of fine particles. In this study, micron-sized particles were introduced to ameliorate the properties of the traditional fluidized bed. The expansion characteristics of the micron-sized-particle-dense medium were explored. A bed expansion prediction model of the micron-sized-particle-dense medium was established, and the prediction error was about 10%, providing a theoretical basis for understanding the distribution characteristics of the bed. This model also helped predict the bed density in the presence of a micron-sized-particle-dense medium, and the prediction accuracy was between 85% and 92%, providing a theoretical basis for selecting and popularizing fluidized beds for industrial separation. [ABSTRACT FROM AUTHOR]

This paper aims to employ the Stokes number to mark aerodynamic penalties of airfoils caused by particles, which is crucial to implement their scaling experiments in a gas‐solid flow. Each Stokes number is associated with a series of approximate aerodynamic penalties which are obtained at the same Reynolds number with different chord lengths. In the process, two phenomena which go against the mark are discussed and their mechanisms are revealed. The results show they occur at smaller and larger ranges of Stokes number, respectively. The effect of gravity is the leading cause and a larger chord length or diameter particle can strength its effect. The application scope of the mark, meanwhile, is ascertained. A chord length smaller than 1.5 m is advised at Re = 1.00 × 106 and those at other Reynolds numbers are also presented. As Stokes number decreases from 3, the aerodynamic penalty increases exponentially first at the advised chord length and reaches up to their peak values at the Stokes number of 0.050. In addition, the change of the aerodynamic penalty with Stokes number is dominated by the momentum exchange in the direction of gravity in the region between the particle injection plane and the airfoil. [ABSTRACT FROM AUTHOR]

The CFD-DEM methodology is a popular tool for the study of fluid-particle systems, and there are several programs that permit using it. In this study, we employed it to simulate a pseudo-2D spouted bed, comparing the performance of the programs Ansys Fluent and MFiX. The results are analysed and commented on in terms of both accuracy and computational efforts. Despite the similarity of the setup, MFiX seems to perform significantly better. The similarities and differences between the two programs are discussed in detail, offering useful insights to researchers regarding the selection of one over the other, depending on the application. The better suitability of the Di Felice drag model is confirmed for the device, while it is shown that the effect of the Magnus lift force may be more limited than was shown in a previous study. [ABSTRACT FROM AUTHOR]

The electric field distortion along the gas-solid interface on insulators in GIS or GIL greatly threatens their long-term insulation performance. In recent years, with the developments of field grading materials, their application on GIS/GIL insulators has been considered as an effective approach to suppressing the field distortion and enhancing the insulation property. Many reviews about field grading materials had been published. However, these articles rarely focus on the nonlinear materials and their unique characteristics when used in gas insulated equipment. Compared with traditional applications, such as cable accessories, generator coils, and motor stator bars, nonlinear materials in GIS/GILs are mainly used for grading the surface electric field and avoiding unwanted charge accumulations. Hence, there are two characteristics of the material that need to be paid special attention to-the surface insulation performances and the charge release functions-which are not so critical in previous applications. In this paper, first, types and principles of several commonly used nonlinear grading materials are summarized briefly. Then, the existing application cases of nonlinear materials in gas insulation equipment are sequentially introduced from the optimization ideas, material selection, manufacturing process, and using effects. Finally, the problems encountered in the application of field grading materials in practice are discussed. Suggestions for the follow-up studies are given in order to guide the application of nonlinear materials in GIS/GIL insulators. [ABSTRACT FROM AUTHOR]

The design and construction of molecular nanostructures with tunable topological structures are great challenges in molecular nanotechnology. Herein, we demonstrate the molecular engineering of Schiff-base bond connected molecular nanostructures. Building module construction has been adopted to modulate the symmetry of resulted one dimensional (1D) and two dimensional (2D) polymers. Specifically, we have designed and constructed 1D linear and zigzag polymers, 2D hexagonal and chessboard molecular nanostructures by varying the number of reactive sites and geometry and symmetry of precursors. It is demonstrated that high-quality conjugated polymers can be fabricated by using gas-solid interface reaction. The on-demanding synthesis of polymeric architectures with diverse topologies paves the way to fabricate molecular miniature devices with various desired functionalities. [ABSTRACT FROM AUTHOR]

In the present work, the effect of a thermodynamically consistent inelastic interface stress on nanovoid evolution in NiAl is studied. Such interface stress is introduced for the solid–gas interface of nanovoids within the concept of the phase field approach. The Cahn–Hilliard (CH) equation using the Helmholtz free energy describes the evolution of nanovoid concentration. The interface stress changes the total stress distribution and affects the elastic stress field. Thus, due to the significant effect of the elastic energy on nanovoid dynamics, it can indirectly affect nanovoid nucleation and growth. The highly nonlinear coupled CH and elasticity equations are solved using the finite element method and the COMSOL code. The coupling appears due to the presence of the nonlinear nanovoid inelastic strain in the total strain, the presence of the nonlinear inelastic interface stress in the stress tensor and the presence of elastic energy in the Helmholtz free energy. Several examples of thermal-induced nanovoid evolutions are presented to investigate the effect of the solid–gas interface stress. The obtained results show the significant effect of the interface stress on the total stress distribution, and consequently a different distribution of thermodynamic driving force which can affect the nanostructure evolution and the deformation. Mainly, the interface stress represents a promotive effect on nanovoid growth which results in a faster nanovoid growth and a larger nanovoid concentration and region. [ABSTRACT FROM AUTHOR]

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A single-field representation is derived to describe a multi-species gas flow seeded with perfectly rigid, non-porous and partially inert particles. Indeed, the latter are not involved in heterogeneous reactions with the gas phase (no consumption of the solid by the gas), but they are expected to potentially undergo adsorption and recombination of gaseous radicals on their surface, resulting in the desorption of stable species into the gas. In this work, integral balances are first established at the gas–solid interface, consistent with the local single-phase equations for reactive multi-species gas flow. This allows rigorous derivation of the jump equations that apply at the gas–solid interface in the presence of surface reactions. Then, the description in terms of local single-phase equations, completed by the jump equations at the interface, is recast into a set of equations for the full domain in the sense of distributions. The result extends Kataoka's formalism (Kataoka, 1986) to reactive gas–solid flow in the presence of both homogeneous and surface reactions. [Display omitted] • Modeling of gas-solid reactive flow suitable for numerical viscous penalty methods. • Rigorous derivation of interface equations in the presence of surface reactions. • Embedding of the reactive two-field representation into a single-field representation. [ABSTRACT FROM AUTHOR]

The demand for sustainable energy has motivated the development of artificial photosynthesis. Yet the catalyst and reaction interface designs for directly fixing permanent gases (e.g. CO2, O2, N2) into liquid fuels are still challenged by slow mass transfer and sluggish catalytic kinetics at the gas-liquid-solid boundary. Here, we report that gas-permeable metal-organic framework (MOF) membranes can modify the electronic structures and catalytic properties of metal single-atoms (SAs) to promote the diffusion, activation, and reduction of gas molecules (e.g. CO2, O2) and produce liquid fuels under visible light and mild conditions. With Ir SAs as active centers, the defect-engineered MOF (e.g. activated NH2-UiO-66) particles can reduce CO2 to HCOOH with an apparent quantum efficiency (AQE) of 2.51% at 420 nm on the gas-liquid-solid reaction interface. With promoted gas diffusion at the porous gas-solid interfaces, the gas-permeable SA/MOF membranes can directly convert humid CO2 gas into HCOOH with a near-unity selectivity and a significantly increased AQE of 15.76% at 420 nm. A similar strategy can be applied to the photocatalytic O2-to-H2O2 conversions, suggesting the wide applicability of our catalyst and reaction interface designs. Photoreduction of permanent gas faces challenges in reactant diffusion and activation at the three-phase interface. Here the authors showed porous metal-organic framework membranes decorated by metal single atoms can boost the photoreduction of CO2 and O2 at the high-throughput gas-solid interface. [ABSTRACT FROM AUTHOR]

The mechanical effects of dilute liquid inclusions on the solid-liquid composite are explored, based on an analytical circular inclusion model incorporating the internal pressure change of the liquid and the surface tension of the interface. Several simple explicit dependences of the stress field and effective stiffness on the bulk modulus and the size of the liquid, the surface tension, and Poisson's ratio of the matrix are derived. The results show that the stresses in the matrix are reduced, and the stiffness of the solid-liquid composite is enhanced with the consideration of either the surface tension or the internal pressure change. Particularly, the effective Young's modulus predicted by the present model for either soft or stiff matrices agrees well with the known experimental data. In addition, according to the theoretical results, it is possible to stiffen a soft solid by pressured gas with the presence of the surface tension of the solid-gas interface. [ABSTRACT FROM AUTHOR]

The demand for DC gas-insulated switchgear/gas-insulated transmission line (GIS/GIL) becomes more and more urgent in recent years owing to the rapid development of high voltage direct current (HVDC) transmission systems. Insulators in DC GIS/GIL could easily accumulate a large number of charges on its surface during long-term operation, which might lead to overstressing of polymeric insulation or surface flashover. Therefore, it is of great significance to propose an effective method for dissipating extra surface charges. However, achieving charge dissipation without opening the tank is still a great challenge to SFC6-insulated equipment for a long time. In this paper, a novel method, which is named X-ray based non-contact charge dissipation method (XNCDM) for insulators in SF6-insulated equipment, is proposed. The effects of X-ray irradiation on the charges dissipation and the influences of irradiation dose were experimentally investigated in SF6. The mechanisms underlying are discussed in detail. Results show that surface charges on the insulator can be almost completely dissipated after short-time X-ray irradiation with enough dose, owing to the significant enhancement of electric conduction along the insulator surface and charge neutralization by gas ions near the gas-solid interface. This paper provides a novel technique for realizing rapid surface charge dissipation on the insulator, which is of great significance for a variety of engineering applications of DC GIS/GIL. [ABSTRACT FROM AUTHOR]

Adsorption of gas molecules in metal-organic frameworks is governed by many factors, the most dominant of which are the interaction of the gas with open metal sites, and the interaction of the gas with the ligands. Herein, we examine the latter class of interaction in the context of CO2 binding to benzene. We begin by clarifying the geometry of the CO2-benzene complex. We then generate a benchmark binding curve using a coupled-cluster approach with single, double, and perturbative triple excitations [CCSD(T)] at the complete basis set (CBS) limit. Against this △CCSD(T)/CBS standard, we evaluate a plethora of electronic structure approximations: Hartree-Fock, second-order Møller-Plesset perturbation theory (MP2) with the resolution-of-the-identity approximation, attenuated MP2, and a number of density functionals with and without different empirical and nonempirical van der Waals corrections. We find that finite-basis MP2 significantly overbinds the complex. On the other hand, even the simplest empirical correction to standard density functionals is sufficient to bring the binding energies to well within 1 kJ/mol of the benchmark, corresponding to an error of less than 10%; PBE-D in particular performs well. Methods that explicitly include nonlocal correlation kernels, such as VV10, vdW-DF2, and ωB97X-V, perform with similar accuracy for this system, as do ωB97X and M06-L. [ABSTRACT FROM AUTHOR]

Comprehensive knowledge and understanding of the breakdown behavior of solid–gas interfaces are important for the development, optimization, and coordination of insulation in practical high-voltage (HV) gas-insulated systems (GISs) that are widely used in the power and pulsed power industries. However, despite significant research efforts focused on the characterization of the breakdown parameters and properties of complex gas-filled HV systems, the basic mechanisms that underpin the development of discharges in such solid–gas topologies are not fully understood. This lack of knowledge is particularly noticeable in the case of solid–gas interfaces stressed with HV impulses. This study is aimed at the experimental investigation of the breakdown behavior of solid–gas interfaces, formed between solid dielectrics and common gases: dry air, N2, and CO2 at atmospheric pressure. Four different solid-dielectric materials, PTFE, HDPE, Delrin, and Macor, with relative permittivities in the range from 2.1 to 6.3, were used in this work. The solid–gas interfaces formed by these dielectric materials and the surrounding gases were stressed with positive and negative HV impulses. The breakdown voltage and time to breakdown were obtained for all combinations of solid–gas interfaces using both positive and negative impulses, with a nominal rise time of $\sim 1.9~\mu \text{s}$. A digital camera operated in the open-shutter regime was used to obtain images of the breakdown spark channels that were classified according to their propagation paths. The results obtained in this study will help in further understanding of the breakdown behavior of solid–gas interfaces and can be used in the development and optimization of dielectric topologies for use in GISs. [ABSTRACT FROM AUTHOR]

Sulfur hexafluoride (SF6) is widely used in the power industry because of its excellent insulation and arc extinguishing performance. However, the high greenhouse effect of this material is being restricted by many countries around the world, thereby discouraging its usage. As a potential alternative to SF6, the compatibility of C5F10O with conductive copper materials used in electrical equipment is of great significance in ensuring the safe and stable operation of environmentally friendly gas-insulated equipment. In this paper, the interaction among C5F10O/N2, C5F10O/air gas mixture, and copper was studied via experiments and simulations. When the C5F10O/N2 (or air) gas mixture comes in contact with copper at the gas–solid interface, a small portion of C5F10O is decomposed to form C3F6 (or C3F6 and C3F6O) at high temperatures. Meanwhile, at low temperatures (120 °C), the C5F10O/air gas mixture becomes more compatible with copper than with the C5F10O/N2 gas mixture. When the experiment temperatures range between 170 °C and 220 °C, the compatibility of the C5F10O/air gas mixture with copper is significantly inferior to its compatibility with copper. Under high temperatures, the C5F10O/air gas mixture shows severe corrosion on the copper surface due to the presence of O2, forms a thick cubic grain, and emits irritating gases. The simulations show that the carbonyl group in C5F10O is chemically active and can be easily adsorbed on the copper surface. An anti-corrosion treatment must be performed on copper materials in manufacturing equipment. The findings provide an important reference for the application of C5F10O gas mixture. [ABSTRACT FROM AUTHOR]

The electric field distributions along gas-solid interfaces determine the reliability, lifetimes and sizes of gaseous insulated switchgears/pipelines (GIS/GIL), which also affect the reliability of power systems. In this study, the characteristics of steady and transient electric field distributions were first introduced, followed by the concept of functionally graded materials (FGMs). The development histories of FGM applied in electrical engineering and the related optimisation methods were described in detail. The field regulation effect and fabrication technology of different FGM insulators were also compared. To overcome the limitations of traditional FGM insulators, the design of surface FGM (SFGM) was proposed, together with their preparation methods and electrical performance. Furthermore, the future development prospects of FGM and SFGM insulators for compact GIS/GIL were summarised.

The exploration and development of unconventional resources have been of growing interest in the industry in recent years. It is widely known that the adsorption and desorption mechanisms of unconventional gas have great significance for gas accumulation and exploration. However, major researches based on the mechanism of solid-gas interface have failed to reveal it completely, which introduce large discrepancies between actual and predicted production. In this paper, the mechanism of solid-liquid-gas adsorption and desorption interface is enlightened to describe the characteristics of unconventional gas. The validity of the proposal was verified preliminarily by building a conceptual model which redefines the gas-water distribution. Furthermore, the possibility of production of gas trapped in micropores was first investigated. The findings of this study can help for better understanding of the adsorption, desorption, and production mechanisms and in unconventional gas system. Accordingly, the explanation of variation between experiment result and actual production rate even with physical parameters was reasonable in theory. Therefore, this work should provide a basis for improving the accuracy of production predictions in actual reservoirs and should assist analysts in determining reasonable unconventional gas target. [ABSTRACT FROM AUTHOR]