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• A novel core–shell CM-P was prepared via a facile cation-driven electrostatic self-assembly strategy. • The charge redistribution in CM-P heterostructures was observed. • The CM-P cathodes exhibited a high specific capacity of 260 mAh/g. • The CM-P//Zn ZISCs showed a high energy density of 217.1 Wh kg−1 along with power density of 22.3 kW kg−1. Rechargeable aqueous Zn-ion hybrid supercapacitors (ZISCs) with the superiorities of high theoretical capacity, low redox potential and aqueous electrolytes with superior ionic conductivity (∼1 S cm−1) are promising energy storage systems. However, a primary concern persists due to the absence of cathode materials with both high energy densities and satisfactory cycling stability for robust ZISCs. In this study, we design a spherical core–shell covalent organic frameworks@Ti 3 CN MXene (CM-P) cathode via a cation-driven electrostatic self-assembly strategy. The CM-P with the constructed heterostructures shows both well-organized pore channels and excellent intrinsic conductivity, facilitating fast accessibility to intrinsic redox-active sites (such as C = O and N), and promoting effective ion diffusion characterized by low energy barriers. Consequently, the CM-P cathodes demonstrate excellent electrochemical performance, featuring an ultrahigh specific capacity of 260 mAh/g at 0.1 A, a high-rate capability with 68 % retention at 1 A/g, and long-term cycling stability. First-principle calculations elucidate that the enhanced charge-storage mechanism relies on the heterostructures of CM-P, accelerating ion adsorption/diffusion and electron transfer. Furthermore, the assembled CM-P//Zn ZISCs devices show a high energy density of 217.1 Wh kg−1 along with power density of 22.3 kW kg−1. This work provides an innovative approach to design COFs-based heterostructures for advanced ZISCs. [ABSTRACT FROM AUTHOR]

Aliphatic aldehydes are a class of organic compounds containing aldehyde groups, which are widespread, and closely related to people's daily life and health. In this work, a series of terpenes based hydrophobic deep eutectic solvents were designed and synthesized using hexafluoroisopropanol as hydrogen bond donor and menthol/thymol as hydrogen bond acceptor. Then they are used as extraction solvent in dispersive liquid-liquid microextraction for extracting and determining seven aliphatic aldehydes from drinking water and alcoholic beverage combined with high performance liquid chromatography-ultraviolet. Due to the fact that these hydrophobic deep eutectic solvents are liquid at the room temperature, a density greater than that of water, a lower viscosity (≤26.10 mPa s, 25 °C), after extraction and centrifugation, the microvolume DES-rich phase in the bottom is convenient for collection and direct analysis without further dissolution or dilution with organic solvents. Some factors affecting the extraction recovery were optimized by one-variable-at-a-time and response surface methodology. Under the optimal conditions, the enrichment factors for the seven aliphatic aldehydes were 48–56. The method had good performance: linear ranges of 1.0–200, 0.5–200, 0.2–200, 0.4–400, 1.0–400, 0.4–400 and 0.4–400 μg L−1 for seven aliphatic aldehydes (r 2 ≥ 0.9949), limits of detection of 0.1–0.5 μg L−1, intra-day and inter-day precisions <4.9%. The recoveries of seven aliphatic aldehydes ranged from 76.0 to 119.0%. The proposed dispersive liquid-liquid microextraction method is simple, rapid, highly efficient, and green, which effectively reduces the amount of toxic chemical reagents used and their impact on the environment. Rapid and efficient detection of aliphatic aldehydes helps ensure a healthy diet and has great application prospects in food safety analysis. [Display omitted] • Terpenes based HDESs with low viscosity and high density were designed and prepared. • A terpenes HDESs based DLLME was established for enrichment of aliphatic aldehydes. • The DES-rich phase in the bottom is easy to be collected and directly analyzed by HPLC. • The method is simple, rapid, effective and green for detecting aliphatic aldehydes. • The green profile of the method was assessed by AES and AGREE. [ABSTRACT FROM AUTHOR]

Ti 3 AlC 2 ceramic exhibits potential in Ag-based composite electrical contact materials, but its interface characteristic with Ag matrix remains unexplored. In this work, sessile drop experiment is carried out to investigate the high-temperature wetting behavior of molten Ag with Ti 3 AlC 2. Stable Ti 3 AlC 2 is hardly wetted by molten Ag below 1000 °C(contact angle of 148.5°), but the wettability of Ag/Ti 3 AlC 2 improves with the increasing temperature(final 14° at ∼1130 °C). In contrast, the Ti 3 C 2, a MXene with Al layer removed from its parent Ti 3 AlC 2 , exhibits inferior wettability with Ag(final 56.5° at ∼1130 °C). Wetting mechanism of Ag/Ti 3 AlC 2 is proposed on the basis of the interfacial structure and chemical composition. Increasing temperature accelerates dissociation of Ti 3 AlC 2 , and outward-escaping Al reacts with Ag to form interface layer with a composition of Ag 4.86 Ti 8.66 AlC 7.59 , Ag also diffuses along Ti 3 AlC 2 grain boundaries and forms gradient reactive products(Ag–Ti–Al–C), which promotes their wettability. Finally comprehensive properties of Ag/Ti 3 AlC 2 and Ag/Ti 3 C 2 are compared. Al–Ag interdiffusion slightly decreases the electrical conductivity of Ag/Ti 3 AlC 2 bulk material, but strengthen the interface bonding of composite and promote the viscosity of the molten pool, leading to the superior mechanical and anti-arc erosion properties. Absence of Al–Ag interdiffusion does remarkably improve the electrical conductivity of Ag/Ti 3 C 2 bulk materials, but lack of Al layer damages the mechanical core and wettability with Ag, resulting in a drastic decrease of anti-arco erosion property. [ABSTRACT FROM AUTHOR]

Ti 3 AlC 2 ceramic-reinforced Ag matrix composites exhibit superior electrical contact performance. However, the arc corrosion mechanism of the Ti 3 AlC 2 reinforcing phase has not been clarified; in particular, the intrinsic relationship between the microstructure and mechanical properties needs to be further explored. In this work, by combining micro/nano-indentation, microstructural and chemical composition analysis, COMSOL simulation, and accelerated aging experiments, the relationship among phase transition, microstructural evolution, and macro/micro/nano-mechanical property changes were compared and analyzed. The cycles of arc discharge produced heat accumulation, which was transmitted from the contact surface to the interior in a gradient (divided into Areas α , β , γ). Changes in the structural dissociation, oxidation, and interfacial bonding of Ti 3 AlC 2 with the Ag matrix resulted in different micro/nano-mechanical properties in these areas in terms of micro-hardness, nano-hardness, modulus, and elastic-plasticity. These findings demonstrate the key role of the phase and microstructural evolution of Ti 3 AlC 2 on the mechanical properties of such composites while also providing a mechanical theoretical basis for future structural design and interfacial optimization of eco-friendly Ti 3 AlC 2 -reinforcing phases in Ag matrix composites. [ABSTRACT FROM AUTHOR]

A serious problem with integrated masonry linings ladle was that the ladle wall bricks were difficult to be partially replaced. Thus, the service life of the ladle was determined by the properties of ladle wall bricks. In this study, the new generation of MgO–Al 2 O 3 –C bricks with bauxite aggregates was tested in a ladle lining of an integrated steel ladle for 103 cycles, and the corroded microstructure of the used brick was investigated. A multilayered structure of bauxite aggregates could be observed in the used brick, which inhibited the slag penetration along the boundary of the magnesia aggregates and reduced the degree of the aggregates fall off from the used bricks. Besides, during the process of slag penetration, bauxite aggregates could melt into the slag, which increased the viscosity of the slag and weakened the penetration ability of the slag. The MgO–Al 2 O 3 –C bricks with bauxite addition could improve the service life of the ladle to a certain extent. [ABSTRACT FROM AUTHOR]

[Display omitted] • Eruption of the rising bubbles causes the sand particles to be elutriated. • Lateral fuel injection leads to a non-uniform distribution of fluxes and gas species. • Temperature variation at z = 0.5 m leads to the sudden changes in gas thermal properties. • The HTC of sand particles ranges from 80 to 200 W/(m2·K) in the BFBG. • Sand particles have a larger Rep in the bubble phase but a smaller Rep in the dense phase. A reactive multiphase particle-in-cell approach is developed to explore the air-blown coal gasification in a bubbling fluidized bed reactor. The model is validated by comparing the predicted bed hydrodynamics and product yields with experimental data. Subsequently, the gas thermal properties and particle-scale behaviours are comprehensively explored. The results show that: (i) the density difference between two solid species gives rise to spatial segregation, which further affects the gasification process. The presence of coal feeding port causes the non-uniform distribution of bed hydrodynamics. (ii) the combustible gases species distribute above the coal feeding port. The concentration of gas species continuously increases while the gas temperature changes little in the dense region. (iii) the slip velocity of sand particles ranges from 0 to 4 m/s; the temperature ranges from 1000 K to 1150 K, and the heat transfer coefficient ranges from 80 W/(m2·K) to 200 W/(m2·K). Compared with sand, coal particles have a larger heat transfer coefficient and particle Reynolds number (Rep). Coal particles reach the maximum temperature of about 1100 K in the period of 3 s after being injected into the bed. (iv) bubble and emulsion phases give a larger Rep and smaller Rep due to the dominant role of the interphase drag force and inter-particle collision force, respectively. [ABSTRACT FROM AUTHOR]