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[Display omitted] • A combined theory–experiment rational design strategy is employed. • Multi-method calculations revealed transformation of molybdates during OER. • A hollow sandwich-like FeOOH/(NiCo)MoO 4 heterostructure was fabricated. • FeOOH/(Ni 1 Co 1)MoO 4 shows super alkaline OER, ƞ 10 = 225 mV, ƞ 200 = 318 mV, ƞ 1000 = 546 mV. • FeOOH/(Ni 1 Co 1)MoO 4 shows a specific capacity of 342 mA h g−1 at 1 A g−1. Structural engineering, including electronic and geometric modulations, is a good approach to improve the activity of electrocatalysts. Herein, we employed FeOOH and the second metal center Ni to modulate the electronic structure of CoMoO 4 and used a low temperature solvothermal route and a chemical etching method to prepare the special hollow hierarchical structure. Based on the prediction of multi-method calculations by density functional theory (DFT) and ab initial molecular dynamics (AIMD), a series of materials were fabricated. Among them, the optimal hollow FeOOH/(Ni 1 Co 1)MoO 4 by coating (NiCo)MoO 4 nanosheets on FeOOH nanotubes showed excellent performances toward high current density oxygen evolution reaction (OER) in alkaline and simulated seawater solutions, hybrid supercapacitor (HSC), and aqueous battery due to the well-controlled electronic and geometric structures. The optimal FeOOH/(Ni 1 Co 1)MoO 4 required overpotentials of 225 and 546 mV to deliver 10 and 1000 mA cm−2 current densities toward alkaline OER, and maintained a good stability for 100 h at 200 mA cm−2 with negligible attenuation. The FeOOH/(Ni 1 Co 1)MoO 4 //Pt/C electrolyzer exhibited a low cell voltage of 1.52 and 1.79 V to drive 10 and 200 mA cm−2 and retained a long-term durability nearly 100 h at 1.79 V. As the electrode of energy storage devices, it possessed a specific capacity of 342 mA h g−1 at 1 A g−1. HSC and SC-type battery devices were fabricated. The assembled HSC kept a capacitance retention of 94 % after 10,000 cycles. This work provided a way to fabricate effective and stable multifunctional materials for energy storage and conversion with the aid of multi-method calculations. [ABSTRACT FROM AUTHOR]

Carnivorous plants adapt to variations in nutrient availability and shade by altering investment in carnivory in response to different environmental conditions. It is not clear, however, how carnivorous plants might alter investment in carnivory in relation to habitat heterogeneity at small scales. We hypothesised that the carnivorous plant Drosera rotundifolia would alter investment in carnivory and the amount of plant nitrogen (N) derived from prey in response to differences in shade and nutrients between hummock and hollow microforms on patterned peatlands. We investigated D. rotundifolia growing on three peatlands in Northern Europe: Scotland, Sweden, and Finland where we expect microhabitat variability to differ between peatlands due to differences in the ratio of precipitation to evapotranspiration. We measured differences in the density of sticky leaf tentacles (investment in carnivory) and the proportion of plant N that was prey‐derived (%Ndfp) for plants growing on hummocks and hollows at each peatland. At the Finland site P:ET ratio was lowest (1.86), and root N availability was similar for hollows and hummocks. Here, tentacle density and %Ndfp were ~50% higher for plants on hollows than on the more shaded hummocks. At the Scotland site P:ET was highest (5.40), root N availability was lower for hummocks than for hollows, and hummocks were more shaded. Here, there was little difference in tentacle density and %Ndfp between plants growing on hummocks and hollows. The Sweden site was intermediate in terms of P:ET ratio (2.63), habitat heterogeneity, and carnivory. Our results are consistent with the predictions of an evolutionary cost–benefit model for plant carnivory in which the marginal benefits of carnivory decrease with increasing root nutrient availability and decreasing light. This model predicted carnivorous plant phenotypic variability at small scales in response to different extents of habitat heterogeneity at our three study sites. Our study demonstrates the capacity for a carnivorous plant species to vary investment in carnivory, adjusting the proportion of prey‐derived N, in response to small‐scale habitat heterogeneity. We suggest that as well as an adaptation to low‐nutrient conditions, carnivory may also provide a means for plants to adapt to and persist in heterogeneous habitats. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Hollow cylindrical components of longer length are a crucial necessity in industries catering to products like gun barrels, cylinder liners of ship and locomotive engines, pneumatic and hydraulic cylinders, etc. A highly finished inner surface improves resistance to corrosion, wear, and friction. Conventional magnetorheological (MR) finishing techniques typically use axis-based CNC setups, which are limited in their ability to finish longer components (>30 cm) due to the Z-axis tool restriction. In this work, a novel MR finishing method has been designed and developed that is based on the pneumatic cylinder and has extremely high reach for the length of the hollow cylindrical workpiece thereby successfully mitigating the limitation of conventional CNC-based MR finishing techniques. Using mild steel as the material, the new technique achieved a significant reduction in surface roughness, with a minimum average roughness of 0.059 µm after 150 minutes of finishing. [ABSTRACT FROM AUTHOR]

Developing oxygen evolution reaction (OER) electrocatalysts in an efficient strategy, while maintaining high catalytic activity and stability under high current densities, remains a crucial problem. In this study, a bimetallic iron‐cobalt phytic acid complex loaded with polyaniline hollow structure (FCP@PAn) was successfully constructed, via a progress of selective etching and surface modification in one step without high‐temperature phosphating or carbonization. The as‐obtained FCP@PAn required only 329 and 385 mV overpotentials at high current densities of 500 and 1000 mA cm−2, respectively, due to phytic acid and polyaniline incorporation and the coordinated effect of each component. Additionally, the FCP@PAn exhibited the lowest Tafel slope values of 44.6 mV dec−1 and was able to continuously operate for 120 h at 500 mA cm−2, displaying high catalytic activity and stability. Hence, the hollow structure of the conductive polymer and MOFs composites provided a new surface modification strategy for transition metal‐based catalysts that are prone to dissolution or corrosion during the OER process, as well as for high current density applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel ReS 2 /CoS 2 /NiS 2 Z-scheme heterojunction was constructed for photocatalytic hydrogen production. • The hollow dodecahedron would provide abundant specific surface areas. • The efficient spatial charge separation and accelerated surface reaction boost photocatalytic hydrogen production. The high efficient utilization of light absorption and the effective separation of photogenerated carriers are critical factors in enhancing the performance of photocatalysts. In this study, CoNi-layered double hydroxide was synthesized using zeolitic imidazolate frameworks-67 as a template, followed by calcination to form CoS 2 /NiS 2. Subsequently, ReS 2 was deposited onto the surface of CoS 2 /NiS 2 , resulting in the ReS 2 /CoS 2 /NiS 2 photocatalyst demonstrated notable hydrogen evolution activity under visible light, achieving a maximum hydrogen production rate of 40111.8 μmol/g. The construction of the Z-scheme heterojunction was found to facilitate the transfer and separation of photogenerated carriers while extending the lifetime of photogenerated electrons, thereby contributing to the enhancement of photocatalytic activity. This study provides a new approach for the development of sulfide heterojunctions aimed at improving photocatalytic hydrogen production efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] The growing demand for clean and sustainable energy has driven extensive research into efficient photocatalysts for hydrogen production. However, many semiconductor photocatalysts in this field still face the challenges such as wide band gap, limited visible light absorption, and inefficient separation and transport of photoinduced charges. In this study, nickel–cobalt layered double hydroxide (NiCo-LDH) was synthesized using an "etch-and-grow" method with zeolitic imidazolate framework-67 (ZIF-67) as a sacrificial template, followed by high-temperature calcination to produce nickel–cobalt mixed metal oxide (NiCo-MMO). Zn 0.3 Cd 0.7 S quantum dots were used to modify NiCo-MMO resulting in a hollow dodecahedral Zn 0.3 Cd 0.7 S@NiCo-MMO composite photocatalyst. In hydrogen production performance test, the optimized Zn 0.3 Cd 0.7 S@NiCo-MMO exhibited excellent performance (8177.5 μmol·g−1·h−1) and demonstrated good cycling stability. The hollow dodecahedral structure of the Zn 0.3 Cd 0.7 S@NiCo-MMO enhanced the light trapping ability and provided large surface area. The p-n heterojunction formed within Zn 0.3 Cd 0.7 S@NiCo-MMO accelerated carrier separation and transfer, effectively inhibited the recombination of photogenerated electrons and holes, and significantly improved the hydrogen production activity. [ABSTRACT FROM AUTHOR]

Hydrogen energy produced through photocatalytic water splitting is widely recognized as a viable solution to the depletion of non-renewable energy resources and ecological contamination concerns. This work designed and synthesized the MOF-derived hollow octahedral Co x P/MOF-801 p-n heterojunction photocatalyst. According to the result of hydrogen production test, the hydrogen production amount of Co x P/MOF-801-2 could reach 25.31 mmol g−1 under light irradiation for 5 h. The hollow octahedral structure and p-n heterojunction of the photocatalyst helped to enhance the light trapping ability and promote carrier transfer, resulting in improved performance of photocatalytic hydrogen production. To sum up, the design of hollow octahedral Co x P/MOF-801 photocatalyst effectively improved the photocatalytic hydrogen production performance. [Display omitted] • MOF-derived hollow octahedral MOF-801 was synthesized and modified with Co x P nanoparticles. • The p-n heterojunction inhibited the recombination of electrons and holes. • The Co x P/MOF-801 exhibited excellent hydrogen production activity and stability. [ABSTRACT FROM AUTHOR]

As the advancement of brushless direct current (BLDC) motor is rising, it has been an advantage to use the motor for a wide range of applications. Its robustness and torque development have benefited small applications, such as the agriculture cutter. However, dropping performances of conventional BLDC are affected by the shape of the rotor that has unused magnetic flux. Therefore, this research aimed to analyze the electromagnetic torque by reducing the unused flux from an electromagnetic point of view. Two BLDC models with different slot-pole numbers and rotor types were modeled and simulated with equal permanent magnet volume, and magnetomotive force (MMF). Finite element method (FEM) software was used to compute backelectromotive force (BEMF), cogging torque, electromagnetic torque, and magnetic flux density of the BLDC models. As a result, 9/8 slot-pole with zero ferromagnetic underneath the permanent magnet had the highest BEMF and torque produced compared to the conventional type, with a percentage difference of 27%. In conclusion, this research presents the motor that had an improvement of electromagnetic torque for electrical cutter application. [ABSTRACT FROM AUTHOR]

Light reflection and diffusion mechanism in the crystalline phase-controlled BSS-HNPs. [Display omitted] • This is the first study on black hollow TiO 2 nanoparticles that can be applied as a painting pigment to correlate the color and the change in the crystal system in the LiDAR application field. • Various crystalline-phase black hollow nanoparticles were synthesized using a simple sol–gel method, followed by calcination at different temperatures, NaBH 4 reduction, and etching. The formation of nanomaterials was analyzed using various methods, and the change in bandgap energy following the crystalline phase was determined using the DFT calculation method.. • Examining the conversion of crystalline phases from anatase to rutile on TiO 2 and exploring the connection between bandgap energy, refractive index, and NIR reflectance have resulted in significant enhancements in NIR reflectance. • True blackness and the change in the refractive index for NIR reflectance were thoroughly explained by the light reflection mechanism, light interference effect, and bond length of the crystal system. The development of highly NIR reflective black single-shell hollow nanoparticles (BSS-HNPs) can overcome the Light Detection and Ranging (LiDAR) sensor limitations of dark-tone materials. The crystalline phase of TiO 2 and the refractive index can be controlled by calcination temperature. The formation of hollow structure and the refractive index is expected to simultaneously increase the light reflection and LiDAR detectability. The BSS-HNPs are synthesized using the sol–gel method, calcination, NaBH 4 reduction, and etching to form a hollow structure with true blackness. The computational bandgap calculation is conducted to determine the bandgap energy (E g) of the white and black TiO 2 with different crystalline structures. The blackness of the as-synthesized materials is determined by the Commission on Illumination (CIE) L * a * b * color system. The hydrophilic nature of BSS-HNPs enables the formulation of hydrophilic paints, allowing the mono-layer coating. With the synergistic effects of hollow structure and the refractive index, BSS-HNPs manifested superb NIR reflectance at LiDAR detection wavelengths. The high detectability, blackness, and hollow structure of BSS-HNPs can expand the variety of LiDAR-detectable dark-tone materials. [ABSTRACT FROM AUTHOR]

Hollow silica nanoparticles (HSNPs) have hygroscopic properties because of their high specific surface area and surface hydroxyl groups. However, compared with other hygroscopic materials, their hygroscopic properties are relatively weak, which limits the further application of HSNPs. One feasible method to enhance their hygroscopic properties is by combining highly hygroscopic materials with hollow silica nanoparticles. To take advantage of the high hygroscopicity of polyacrylic acid (PAA) when combined with the high specific surface area of the hollow particles, PAA was coated on the inner and outer surfaces of the silica shell of the nanoparticles in this study to prepare hollow nanoparticles with a PAA/silica/PAA multilayer structure. The size of the PAA/silica/PAA multi-layer nanoparticles is about 85 nm, and the shell thickness is 25 nm. The specific surface area of the multi-layer nanoparticles is 58 m2/g. The water vapor adsorption capacity of multi-layer structure hollow nanoparticles was increased by 160% compared with the HSNPs (increased from 45.9 cm3/m2 to 109.1 cm3/m2). Meanwhile, at the same content of PAA, the PAA/silica/PAA-structured particles will adsorb 9% more water vapor than the PAA/silica-structured particles. This indicates that the high specific surface area structure of the hollow particles will enhance the adsorption ability of PAA toward water vapor. This novel structure of PAA-HSNPs is expected to be used as a humidity-regulating material for filler in environmental and architectural applications. [ABSTRACT FROM AUTHOR]

Currently, there is not much research on strengthening structural elements with hollows. This manuscript presents the test results from twelve circular reinforced concrete column specimens strengthened with CFRP strips. This study focuses on the strain behavior of longitudinal reinforcement and CFRP strips due to high shear force intensity. Hollows in the cross-section are used to see the effect of voids on the column strain distribution. Nine specimens have a hollow cross-section with hollow diameters of 1.5", 2.5", and 3.5" for each of the three specimens. Meanwhile, the other three specimens have a solid crosssection. All specimens do not use stirrups to determine the contribution of concrete and CFRP strips to resist shear. Strain gauges are placed in certain positions to read the strain on the longitudinal reinforcement and CFRP strips. The test results are in the form of tensile forces and are then analyzed to obtain the movement pattern of tensile forces in the longitudinal reinforcement and CFRP strips. Numerical analysis using a fiber element model is used to obtain the strain in each reinforcement layer. The numerical analysis results were then compared with the test results and showed close results. Then, an equation for calculating the tensile force in CFRP strips is proposed. The proposed equation approximates the test results with an accuracy level of 90%.

The forage quality of alfalfa (Medicago sativa) stems is greater than the leaves. Sucrose hydrolysis provides energy for stem development, with starch being enzymatically converted into sucrose to maintain energy homeostasis. To understand the physiological and molecular networks controlling stem development, morphological characteristics and transcriptome profiles in the stems of two alfalfa cultivars (Zhungeer and WL168) were investigated. Based on transcriptome data, we analysed starch and sugar contents, and enzyme activity related to starch-sugar interconversion. Zhungeer stems were shorter and sturdier than WL168, resulting in significantly higher mechanical strength. Transcriptome analysis showed that starch and sucrose metabolism were significant enriched in the differentially expressed genes of stems development in both cultivars. Genes encoding INV , bglX , HK , TPS and glgC downregulated with the development of stems, while the gene encoding was AMY upregulated. Weighted gene co-expression network analysis revealed that the gene encoding glgC was pivotal in determining the variations in starch and sucrose contents between the two cultivars. Soluble carbohydrate, sucrose, and starch content of WL168 were higher than Zhungeer. Enzyme activities related to sucrose synthesis and hydrolysis (INV, bglX, HK, TPS) showed a downward trend. The change trend of enzyme activity was consistent with gene expression. WL168 stems had higher carbohydrate content than Zhungeer, which accounted for more rapid growth and taller plants. WL168 formed hollow stems were formed during rapid growth, which may be related to the redistribution of carbohydrates in the pith tissue. These results indicated that starch and sucrose metabolism play important roles in the stem development in alfalfa. The forage quality of alfalfa (Medicago sativa) stems is greater than the leaves. Starch and sucrose metabolism provide energy during alfalfa stem development. Different varieties of alfalfa have different sucrose, starch and related enzyme activities. Hollow stems will be formed during the rapid growth of alfalfa, which may be related to the redistribution of carbohydrates in the pith tissue. Our results may provide a new theoretical basis for understanding the molecular mechanism of sucrose and starch accumulation in alfalfa stems. [ABSTRACT FROM AUTHOR]

The sluggish Zn2+ diffusion and high nucleation energy barrier induce uncontrolled growth of Zn dendrites and detrimental parasitic reactions, severely hampering the commercialization of Zn metal anodes (ZMAs). Herein, hollow mesoporous carbon sphere opal with confined Sn/TiO2 clusters (HMCSST) is designed as the host to spatially regulate the Zn deposition. Owing to the capillary effect of the ordered hierarchical porous structure, the mass diffusion can be dramatically accelerated to promote a fast deposition kinetics at the interface between ZMA and electrolyte. Besides, the encapsulated ultrafine Sn/TiO2 clusters serve as zincophilic sites to achieve both the uniform Zn deposition on the hierarchical porous opal host and the high thermodynamic stability of ZMAs. Benefiting from the structural and componential merits, the HMCSST host effectively reduces the activation energy to enable a temporal‐spatial ordering of Zn nucleation and growth. As expected, the stable HMCSST‐Zn electrode guarantees steady Zn platting/stripping with long‐term stability over 1300 h in a symmetrical cell at a depth of discharge of 37.5%. As a proof‐of‐concept demonstration, an HMCSST‐Zn||ammonium vanadate full cell shows a long lifespan over 5000 cycles at 10.0 A g−1 with low polarization. [ABSTRACT FROM AUTHOR]

In order to further improve the technical advantages of lightweight prefabricated concrete stairs, a kind of prefabricated stair system using a special-shaped hollow landing slab was proposed. Based on the detailed structural composition display, the design method for the main components (prefabricated flight and special-shaped prefabricated hollow landing slab) was proposed and a design application example was provided. Furthermore, specialized experimental and numerical simulation studies were conducted on the key component—the special-shaped prefabricated hollow landing slab. The research results indicated that this new kind of lightweight prefabricated concrete stairs using a special-shaped prefabricated hollow landing slab has reasonable construction, an effective design method, a clear force transmission mechanism, moderate component weight, and high transportation and installation convenience. [ABSTRACT FROM AUTHOR]

Gelatin and borax were successfully used as cross-linkers to prepare a hydrogel composite. Herein, the hollow hydrogel of graphene/polyaniline nanotube/ZIF-67-nanocages (G/PANI-NT/ZNC) as a ternary composite has been synthesized and applied as the active materials of supercapacitors. Cubic ZNC was prepared using Cu2O cubic nanoparticles as a template through etching and precipitating processes. Accordingly, the ZNCs are uniformly placed on the G/PANI-NT network. The novelty of this work is the synthesis of a new G/PANI-NT/ZNC composite hydrogel with gelatin and borax as cross-linkers and without freeze-drying. The obtained hydrogel indicated a specific surface area (3.57 m2 g−1) and can be utilized as the supercapacitor electrode. The G/PANI-NT/ZNC electrode has a capacitance of 62.10 C g−1 at 10 mV s−1. The specific capacitance of G/PANI-NT/ZNC was far superior to those of G/PANI-NT/Cu-Z (33.36 C g−1) and G/PANI-NT/hydrogels (6.28 C g−1). Furthermore, the G/PANI-NT/ZNC electrode showed 92.2% cycling stableness after 8000 cycles. This work has significant reference importance for directly using nanocages in the synthesis of hydrogels as electrode materials for supercapacitors. Furthermore, the symmetric supercapacitor device was also successfully fabricated on the lab scale using a PVA-Na2SO4 gel electrolyte system, indicating that good performance can be achieved for advanced energy storage devices. [ABSTRACT FROM AUTHOR]

In this study, porous, and hollow nanorods of NiTiO 3 (NiTiO 3 NRs-p: 2–3 μm in length and 400 nm in diameter) are successfully prepared using an ethylene glycol-mediated approach at room temperature (25 °C), followed by calcination at 700 °C in air environment. Their rough surfaces and accumulated holes are advantageous for adsorption and subsequent photoreduction of carbon dioxide (CO 2) under UV–vis irradiation. The NiTiO 3 NRs-p exhibit superior performance in terms of photoconversion of CO 2 (purity 99.999 %, 100 mL/min) into gaseous CO (57.833 μmolg−1 h−1) and CH 4 (24.33 μmolg−1 h−1) with an overall CO 2 selectivity (S CO2) of 89 %. In contrast, the solid NiTiO 3 nanorods (NiTiO 3 NRs) exhibit moderate performance in CO 2 reduction, producing CO (30.33 μmolg−1 h−1) and CH 4 (11.50 μmolg−1 h−1) with a CO 2 selectivity of S CO2 = 60 %. NiTiO 3 NRs-p exhibits superior photocatalytic activity against CO 2 over other NiTiO 3 morphologies with similar physical and chemical properties (such as nanoparticles (NPs) and nanofibers (NFs). This enhancement in photocatalytic activity can be attributed to the porous texture and hollow rod-like structure of NiTiO 3 NRs-p, which provides a larger number of active sites to promote rapid mass transport. This unique one-dimensional (1D) structure also facilitates the separation of photogenerated electron-hole pairs, as demonstrated experimentally. This study opens a new room for a simple and facile routes for the photocatalytic conversion of CO 2 into solar fuels. [ABSTRACT FROM AUTHOR]

With the research and development of fiber composite winding tubes, this paper proposed an idea of using bamboo skin materials to prepare hollow tubes by hand lay-up process based on fiber winding tube technology, in order to solve the problem of existing bamboo hollow components in the field of civil engineering like radial bending, irregular section, bamboo joints and other problems. In view of the characteristics of brittle failure of bamboo winding tubes, this paper reinforced the outside of the bamboo winding tubes parallel to grain with bamboo skins perpendicular to grain, and studied the influence of different transversely reinforced layers on the overall bearing capacity of bamboo winding tubes. The test results showed that by adding transverse reinforcement to the outside of the bamboo winding tube, its bearing capacity can be effectively improved, making it an ideal column member. In addition, a prediction formula for the compressive strength of transversely reinforced bamboo winding tubes was proposed, and the calculation results of the formula are in good agreement with the test results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrothermal and sol-gel method were combined to prepare carbon microspheres. • Carbon microspheres with multi-layer dendritic hollow structure, high specific surface area and abundant micropores were successfully prepared. • Excellent cycle stability and great specific capacitance were obtained by the supercapacitor prepared from the carbon microspheres. The electrochemical properties of corn starch (CS)-based hydrothermal carbon microsphere (CMS) electrode materials for supercapacitor are closely related to their structures. Herein, cetyltrimethyl ammonium bromide (CTAB) was used as a soft template to form the corn starch (CS)-based carbon microspheres with radial hollow structure in the inner and middle layers by hydrothermal and sol-gel method. Due to the introduction of multi-layer hollow structure of carbon microsphere, more micropores were produced during CO 2 activation, which increased the specific surface area and improved the capacitance performance. Compared to commercial activated carbon, the four different morphologies of corn starch CMS had better electrochemical performances. Consequently, the proposed CO 2 –(CTAB)-CS-CS exhibits a high discharge specific capacitance of 242.5F/g at 1 A/g in three-electrode system with 6 M KOH electrolyte, better than commercial activated carbon with 208.5F/g. Moreover, excellent stability is achieved for CO 2 –(CTAB)-CS-CS with approximately 97.14 % retention of the initial specific capacitance value after 10,000 cycles at a current density of 2 A/g, while the commercial activated carbon has 86.96 % retention. This implies that the corn starch-based multilayer hollow CMS could be a promising electrode material for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous Zn metal batteries are considered as promising next‐generation energy storage device because of their intrinsic safety and low cost. Nonetheless, the poor lifespan stemming from uncontrollable dendrite growth and inevitable parasitic reactions of metallic Zn impede their large‐scale application. Herein, the formation of the hierarchical lotus root‐like Zn/N‐doped carbon hollow nanofibers‐based paper is reported decorated with interconnected Zn/N‐doped carbon nanocages (denoted as LRZCF@ZCC) as a freestanding host with multifunctionality for Zn metal anode. Of note, the interconnected porous structure mitigates the internal stress to ensure robust structure. Besides, the concave surface of inner LRZCF@ZCC channel facilitates the nucleation of Zn2+ to geometrically guide the Zn deposition. Meanwhile, the well‐distributed metallic Zn and N‐doped carbon species can serve as the zincophilic sites to reduce the nucleation overpotential and avoid the evolution of hydrogen bubbles. As expected, the LRZCF@ZCC exhibits low polarization for the controllable Zn deposition with small voltage hysteresis. Both the symmetric cell and the full cell using this unique host demonstrate long‐term cycling duration and enhanced rate capability. [ABSTRACT FROM AUTHOR]

[Display omitted] • NaCl modulated preparation of hollow Co/Co 3 O 4 heterostructure was reported. • The interfacial interaction could modulate electronic structure and facilitate electron transfer. • The hollow nanostructure could promote mesoscale mass diffusion. • H-Co/Co 3 O 4 -NC possessed boosted OER and HER performances as well as excellent overall water splitting. Fabricating an efficient electrocatalyst for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is the most challenging task for overall water splitting. Herein, we utilized the confinement effect of molten sodium chloride (NaCl) to controllably prepare hollow Co/Co 3 O 4 nanoparticles embedded into nitrogen-doped carbon (H-Co/Co 3 O 4 -NC). Experimental and theoretical investigations revealed that the interfacial interaction within Co/Co 3 O 4 heterostructure played a pivotal role in modulating the electronic structure and facilitating the electron transfer. Meanwhile, the superiority of hollow nanostructure could promote the mesoscale mass diffusion. Remarkably, the as-prepared H-Co/Co 3 O 4 -NC catalyst achieved the low overpotentials of 316 mV and 252 mV towards OER and HER, respectively, which delivered overall water splitting with the potential of 1.76 V at a current density of 10 mA cm−2. [ABSTRACT FROM AUTHOR]

This article provides a polyphenol-mediated modulation (PMM) strategy for the controllable assembly of hollow hybrid nanomaterials (HZIF-8/PcFe and HZIF-8@PcFe) with different TA (tannic acid) coating thicknesses to detect dopamine, which exhibit excellent linearity range (0.3–200 μmol/L) with a detection limit as low as 0.1 μmol/L (S/N = 3). [Display omitted] Multiple microenvironmental modulation of zeolite imidazole framework-8 (ZIF-8) is expected to solve the long-term intractable problem of low sensitivity in electrochemical sensing. Herein, the metal phthalocyanines with different central ions (PcM, M = Fe, Co, Ni and Cu) were introduced into ZIF-8 by in-situ synthesis method. Then, the hollow composite nanomaterials, HZIF-8/PcFe and HZIF-8@PcFe (HZIF-8, i.e., hollow ZIF-8) with different TA (tannic acid) coating thicknesses (∼11 nm and ∼33 nm) were successfully fabricated by carefully designed polyphenol-mediated modulation (PMM) strategy. Next, the HZIF-8@PcFe electrochemical sensor was constructed for selective and sensitive analysis by selecting dopamine (DA) as the analyte. The TA coating (superhydrophilic state), PcFe (redox properties) and hollow MOF cavity (faster mass transfer) was used as the triple microenvironment modulation of ZIF-8 to enhance the electrocatalytic performance. Under the optimum conditions (pH = 8.0), the linear correlations of 0.3 to 200 μmol/L was obtained for the peak current response, with a detection limit of 0.1 μmol/L (S/N = 3, i.e., Signal/Noise = 3). Meanwhile, the HZIF-8@PcFe electrochemical sensor exhibited excellent interference selectivity, reproducibility and stability, which enabled it to detect low abundance DA in real samples. And the F-test (homogeneity test of variance) and t -test (student's t test) statistical analyses were employed to enhance the accuracy of the actual samples' detection. This work will enlighten researchers working in the field of porous framework composites and open up new paths for the development of hollow MOFs hybrid materials in electrochemical sensing. [ABSTRACT FROM AUTHOR]

The development of efficient and stable catalyst is crucial for hydrogen evolution reaction (HER) in water electrolysis. The rational design of porous supports can effectively improve the exposure of active sites and increase the electrochemically active surface area of catalysts. In this study, a nanostructured carbon nanoshell (CS) is proposed for the synthesis of ruthenium and nitrogen incorporated carbon catalyst (CS@N-Ru) catalysts. Physicochemical characterization show that the prepared catalyst exhibits a hollow structure and abundant nitrogen/ruthenium related active sites, which enables the improvement of mass transfer and the catalytic activity. The electrochemical tests show that the prepared CS remarkably facilitates the performance of catalyst, the CS@N-Ru500 synthesized at 500 °C exhibits the best catalytic activity with a low overpotential of 35 mV at 10 mA/cm2 and Tafel slope of 38 mV/dec, attributing to the increased electrochemically active surface area, reduced electron/ion transfer resistance, and accelerated kinetics of HER. These findings suggest that the CS@N-Ru can be a promising alternative to Pt/C for HER in water electrolysis. [Display omitted] • Carbon nanoshells was design for the synthesis of electrocatalytic catalyst. • Hollow structure and active sites improve mass transfer and catalytic activity. • The prepared CS@N-Ru exhibits the best catalytic activity towards HER. • The temperature of catalyst preparation was optimized. [ABSTRACT FROM AUTHOR]

In suspended permanent magnet maglev trains, the magnetic field generated by hollow-type permanent magnet synchronous linear motors is one of the main sources of low-frequency electromagnetic fields. To investigate the magnetic field generated by the linear motor in the train, this paper first establishes the 2D and 3D models of the linear motor using ANSYS EM software. Then, the electromagnetic simulation of the magnetic field of the linear motor is performed under conditions of no load and full load. Next, the magnetic field of the motor is measured using a six-channel high-precision magnetic field test system, and the simulation and measurement results are compared. The result analysis indicates that the energy distribution of the electromagnetic field generated by the linear motor is uniform and that the magnetic induction intensity falls within the range of 0 to 1.1 T. Meanwhile, the linear motor can form a closed loop with a small electromagnetic field energy leakage. Combined with its installation structure, the radiation to the surrounding environment is weak, and the interference with the normal operation of the train control communication equipment is minimal. This study lays a foundation for analyzing electromagnetic distribution on the surface of the suspended permanent magnet maglev train. It also provides a basis for formulating various electromagnetic radiation protection measures and provides theoretical support for developing suspended permanent magnet maglev trains.

Designing and fabricating a competent cobalt‐based catalyst for sodium borohydride (NaBH4) hydrolysis is of great importance. The present work reports the synthesis of hierarchical porous hollow core‐shell framework cobalt oxide (HCSCO) via etching and calcination processes, which is then employed for catalyzing NaBH4 hydrolysis. The surface morphology and the hollow core‐shell framework of HCSCO were revealed by scanning electron microscope (SEM) and transmission electron microscope (TEM) analyses; the crystalline structure and the formation of Co3O4 in HCSCO were determined by X‐ray diffraction (XRD) and Raman spectroscopy; the surface area and porosity of HCSCO were verified by N2 adsorption‐desorption isotherm; and X‐ray photoelectron spectroscopy (XPS) was utilized to examine the chemical states of HCSCO. The as‐prepared HCSCO showed prominent catalytic hydrolysis of NaBH4 to generate H2 with a H2 generation rate of 441 ml min−1 gcatalyst−1 and a low activation energy (Ea) of 34.8 kJ mol−1. This Ea value of HCSCO is substantially lower than that of other catalysts, including noble metal catalysts or composites reported in the literature. Besides, HCSCO could remain its superb activity (~100 % H2 generation efficiency) over multiple hydrolysis cycles without significant changes of morphology and microstructure. The catalytic hydrolysis mechanism for H2 generation from NaBH4 using HCSCO is also proposed. This work provides a valuable strategy for the synthesis and fabrication of state‐of‐art catalysts for H2 generation from the hydrolysis of NaBH4. [ABSTRACT FROM AUTHOR]

Due to its excellent electrical conductivity and stable Magnéli phase structures, cermet Ti 4 O 7 has emerged as one of the most promising materials in the fields of electrochemical application. However, the difficulties in creating high specific surface area structures, having room for conductivity enhancement when used as a conductive additive, and passivation forming TiO 2 under sufficiently oxidizing conditions limit the development of Ti 4 O 7 for practical applications. In this work, the V-doped Ti 4 O 7 hollow spheres with improved electrical conductivity and thermal stability were synthesized by the three-step approach of solvothermal reaction, oxidative crystallization, and hydrogen reduction without any surfactant or template. The formation mechanism of hollow (Ti,V) 4 O 7 was revealed by analyzing the valence evolution of V and comparing the morphology of Ti 4 O 7. The conductivity of Ti 4 O 7 and (Ti,V) 4 O 7 was compared and contrasted as functions of pressure, demonstrating the superiority of (Ti,V) 4 O 7 in terms of conductivity. Thermograms showed that the addition of V increased the complete oxidation temperature of Ti 4 O 7. Moreover, the reason for the enhanced electrical conductivity and thermal stability of V-doped Ti 4 O 7 was also revealed based on density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Precious metal Pt‐based electrocatalysts have been widely used in the methanol catalytic oxidation anodes in direct methanol fuel cells. However, decreasing their cost and improving their efficiency and durability have still been challenging. Herein, ternary PtPdCu nanocatalysts are synthesized through a facile one‐step hydrothermal synthesis method. When KI is present with a suitable amount in the synthesis, PtPdCu nanospheres with surface‐embedded CuI clusters (CuI/PtPdCu) are fabricated. However, without KI, the prepared PtPdCu catalysts show a distinct hollow structure (h‐PtPtCu). CuI/PtPdCu displays the highest specific activity with enhancement 4 times higher than commercial Pt/C for the methanol oxidation reaction in an alkaline medium. The superior activity can be attributed to two aspects: 1) the electronic effect originating from the highly alloyed PtPdCu; 2) the synergetic effect resulting from surface inlaid CuI clusters, which can promote the CO intermediate removal. Furthermore, because of the stable Pt–Pd‐rich surface and its special linked hollow structure, the h‐PtPtCu catalyst exhibits good durability with only a 3.6% decay in the specific activity. [ABSTRACT FROM AUTHOR]

Manganese oxide (MnO2) exhibits excellent activity for volatile organic compound oxidation. However, it is currently unknown whether lattice oxygen or adsorbed oxygen is more conducive to the progress of the catalytic reaction. In this study, novel hollow highly dispersed Pt/Copper modified-MnO2 catalysts were fabricated. Cu2+ was stabilized into the δ-MnO2 cladding substituting original K+, which produced lattice defects and enhance the content of adsorbed oxygen. The 2.03 wt% Pt Cu0.050-MnO2 catalyst exhibited the highest catalytic activity and excellent stability for toluene and benzene oxidation, with T100 = 160 °C under high space velocity (36,000 mL g−1 h−1). The excellent performance of catalytic oxidation of VOCs is attributed to the abundant adsorbed oxygen content, excellent low-temperature reducibility and the synergistic catalytic effect between the Pt nanoparticles and Cu0.050-MnO2. This study provides a comprehensive understanding of the Langmuir–Hinshelwood (L-H) mechanism occurring on the catalysts.

In order to further improve the technical advantages of lightweight prefabricated concrete stairs, a kind of prefabricated stair system using a special-shaped hollow landing slab was proposed. Based on the detailed structural composition display, the design method for the main components (prefabricated flight and special-shaped prefabricated hollow landing slab) was proposed and a design application example was provided. Furthermore, specialized experimental and numerical simulation studies were conducted on the key component—the special-shaped prefabricated hollow landing slab. The research results indicated that this new kind of lightweight prefabricated concrete stairs using a special-shaped prefabricated hollow landing slab has reasonable construction, an effective design method, a clear force transmission mechanism, moderate component weight, and high transportation and installation convenience.

Precious metal Pt‐based electrocatalysts have been widely used in the methanol catalytic oxidation anodes in direct methanol fuel cells. However, decreasing their cost and improving their efficiency and durability have still been challenging. Herein, ternary PtPdCu nanocatalysts are synthesized through a facile one‐step hydrothermal synthesis method. When KI is present with a suitable amount in the synthesis, PtPdCu nanospheres with surface‐embedded CuI clusters (CuI/PtPdCu) are fabricated. However, without KI, the prepared PtPdCu catalysts show a distinct hollow structure (h‐PtPtCu). CuI/PtPdCu displays the highest specific activity with enhancement 4 times higher than commercial Pt/C for the methanol oxidation reaction in an alkaline medium. The superior activity can be attributed to two aspects: 1) the electronic effect originating from the highly alloyed PtPdCu; 2) the synergetic effect resulting from surface inlaid CuI clusters, which can promote the CO intermediate removal. Furthermore, because of the stable Pt–Pd‐rich surface and its special linked hollow structure, the h‐PtPtCu catalyst exhibits good durability with only a 3.6% decay in the specific activity.

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As a result of the high theoretical capacities, transition metal sulfides have attracted increasing attention as potential anodes for sodium-ion batteries (SIBs), but severely suffer from large volumetric variations, sluggish kinetics, and polysulfide shuttling. Herein, utilizing metal–organic frameworks (MOFs) as functional templates, heterostructured CoS2/FeS nanoparticles confined in a hollow N-doped carbon framework are successfully fabricated via a controlled ion-exchange reaction combined with subsequent carbonization and sulfurization processes. The construction of CoS2/FeS heterointerfaces promotes electron transfer and provides more active sites, while the derived N-doped carbon framework with a unique hollow interior effectively improves the electrical conductivity, alleviates the volumetric variations, and facilitates the sodium storage process with shortened Na+ diffusion paths. As anodes for SIBs, the optimal CoS2/FeS hybrid composite exhibits a high initial Coulombic efficiency (ICE) of 89.3%, a prolonged cycle life with a capacity of 494 mAh g–1 over 500 cycles under a current density of 1.0 A g–1, and an excellent rate capability of 428 mAh g–1 at 5.0 A g–1, showing the great promise for SIBs. This research offers an efficient and feasible approach for exploring and fabricating bimetallic sulfide heterostructures with a unique hollow structure for high-performance metal-ion batteries. [ABSTRACT FROM AUTHOR]

Titanium silicalite-1 (TS-1) is a milestone heterogeneous catalyst with single-atom tetrahedral titanium incorporated into silica framework for green oxidation reactions. Although TS-1 catalysts have been industrialized, the strategy of direct hydrothermal synthesis usually produces catalysts with low catalytic activities, which has still puzzled academic and industrial scientists. Post-treatment processes were widely chosen and were proven to be an essential process for the stable production of the high-activity zeolites with hollow structures. However, the reasons why post-treatment processes could improve catalytic activity are still not clear enough. Here, high-performance hollow TS-1 zeolites with nano-sized crystals and nano-sized cavities were synthesized via post-treatment of direct-synthesis nano-sized TS-1 zeolites. The influencing factors of the fabricating processes on their catalytic activities were investigated in detail, including the content of alkali metal ions, the state of titanium centers, hydrophilic/hydrophobic properties, and accessibility of micropores. The post-treatment processes could effectively solve these adverse effects to improve catalytic activity and to stabilize production. These findings contribute to the stable preparation of high-performance TS-1 catalysts in both factories and laboratories. [ABSTRACT FROM AUTHOR]

Abstract Azorubin S (ARS) represents one of the most common and frequently-utilized toxic azo dyes produced from industrial activities. While various conventional treatment techniques could not effectively eliminate ARS from water, heterogeneous metal-based catalyst coupled with monopersulfate (MPS) is a highly-efficient process for eliminating ARS, in which tricobalt tetroxide (Co3O4) has been attracted increasing attention as a preeminent MPS activator due to its outstanding physicochemical properties. However, the nanoscale Co3O4 particles usually pose a limitation of serious agglomeration in the aqueous environment, thus lowering their efficiency. Thus, developing an easy-synthesized and exceptionally efficient Co3O4-based catalyst is crucially paramount. Therefore, in this work, a special hollow-structured oval-like cobalt oxide (abbreviated as HOCO) was successfully constructed using Co-metal organic framework as a precursor, which was then utilized for catalyzing activation of MPS to degrade ARS. This as-obtained HOCO exhibited distinct physicochemical characteristics from commercially-available Co3O4, which subsequently resulted in superior activities for MPS activation in ARS degradation. Specifically, 100% of ARS could be degraded in 30 min with a corresponding reaction kinetic of 0.22 min− 1 by HOCO + MPS system. SO4 •– radicals were validated to be primary reactive species for ARS degradation while the degradation pathway of ARS was also elucidated. This study further provides insightful information about the development of novel hollow-structured Co3O4-based catalyst for catalyzing activation of MPS to remove toxic dyes from water.

At present, platinum-based alloys are irreplaceable catalysts for direct methanol fuel cells. How to reduce the amount of Pt and improve its electrocatalytic performance is one of the difficulties in this field. Noble-metal hollow nanocrystals are one of the most promising catalysts due to their high specific surface area and high stability. In this paper, we used the combination of electrochemical displacement reaction and Kirkendal effect to prepare hollow NiPt/C by sacrificial template method, and explore the effect of capping agent content on the electrocatalytic methanol oxidation reaction (MOR) performance of synthetic materials. Electrochemical tests show that the hollow binary catalyst prepared with a capping agent content of 50 mg had the highest electrochemical active area. In particular, 4000-s chronoamperometry tests in acidic solution show that the stability of NiPt/C with hollow structure is enhanced. We ascribe the better catalytic activity to the hollow feature, higher specific electrochemical surface area, and more abundant active sites. [ABSTRACT FROM AUTHOR]

The yolk-shell MIL-125/TiO2/ Pt/CdS and hollow TiO2/Pt/CdS visible-light catalysts were successfully synthesized from MIL-125 by γ-ray irradiation. During the reduction process by γ-ray irradiation, metal organic frameworks are partially or completely hydrolyzed to TiO2 nanosheets, forming the unique yolk-shell or hollow structure. The hydrogen production rate is 2.9835 mmol·g−1·h−1 for yolk-shell structures and 1.9342 mmol·g−1·h−1 for hollow structures under visible-light illumination, which is 7.9 and 5.1 times higher than that of CdS, respectively. The excellent properties of these photocatalysts may be attributed to the effective absorption and utilization of the light, the porous yolk-shell or hollow structure derived from MIL-125 to facilitate mass transfer, and close contact among CdS nanoparticles, TiO2 nanosheets and Pt nanoparticles to improve the separation of electron-hole pairs. This research can provide a simple and new method for the construction of high efficiency photocatalysts derived from MOFs using the γ-ray irradiation. [ABSTRACT FROM AUTHOR]

Delicate modulations of CO2 activation and charge carrier separation/migration are challenging, yet imperative to augment CO2 photoreduction efficiency. Herein, by supporting diethylenetriamine (DETA)‐functionalized Cd0.8Zn0.2S nanowires on the exterior surface of hollow Co9S8 polyhedrons, hierarchical Co9S8@Cd0.8Zn0.2S‐DETA nanocages are fabricated as an S‐scheme photocatalyst for reducing CO2 and protons to produce syngas (CO and H2). The amine groups strengthen adsorption and activation of CO2, while the "nanowire‐on‐nanocage" hierarchical hollow heterostructure with an S‐scheme interface boosts separation and transfer of photoinduced charges. Employing Co(bpy)32+ as a cocatalyst, the optimal photocatalyst effectively produces CO and H2 in rates of 70.6 and 18.6 µmol h−1 (i.e., 4673 and 1240 µmol g−1 h−1), respectively, affording an apparent quantum efficiency of 9.45% at 420 nm, which is the highest value under comparable conditions. Ultraviolet photoelectron spectroscopy, Kelvin probe, and electron spin resonance confirm the S‐schematic charge‐transfer process in the photocatalyst. The key COOH* species responsible for CO2‐to‐CO reduction is detected by in‐situ diffuse reflectance infrared Fourier transform spectroscopy and endorsed by density functional theory calculations, and thus a possible CO2 reduction mechanism is proposed. [ABSTRACT FROM AUTHOR]

Utilization of graphitic carbon nitride (g–C 3 N 4)–based materials for photocatalytic hydrogen production to alleviate energy problems is a hot topic of research nowadays, thus the design and synthesis of highly efficient g-C 3 N 4 materials remains a significant challenge. Herein, the sulphur-doped hollow porous tubular g-C 3 N 4 (S-HPTCN) was successfully synthesized by a facile environmentally friendly supramolecule self-assembly strategy. Photocatalytic H 2 evolution tests show that the as-prepared optimal S-HPTCN achieved a high H 2 production of up to 22.04 mmol g−1 h−1 with the turnover frequency (TOF) of 429.7 h−1 and the apparent quantum efficiency (AQE) of as high as 7.8% at wavelength of 420 nm. The enhancement of remarkable photocatalytic H 2 performance is mainly attributed to the synergetic effect of morphology and elemental doping. This research provides an effective design idea of developing high-efficient g–C 3 N 4 –based material for solar to hydrogen. [ABSTRACT FROM AUTHOR]

The Eastern Horseshoe Bat Rhinolophus megaphyllus is known to roost in caves, disused mines, tunnels and old buildings. Other tropical Rhinolophus species are reported to use tree roosts, but this has not been reported for R. megaphyllus. We describe the features of a R. megaphyllus tree roost identified on the mid north coast of NSW. The tree was monitored over a 10-year period before the tree's collapse during the 2019/2020 wildfires. The tree was not observed to be used in the maternity season. The discovery highlights the potential importance of hollow trees as habitat for species not previously recorded as using tree roosts. In addition, the discovery further identifies the need for consideration of changing fire management with the onset of warming and drying as part of climate change. Prevention of future conflagrations, as was witnessed during 2019/2020 fire season, should consider a range of options to help prevent the loss of valuable hollow-bearing habitat trees. [ABSTRACT FROM AUTHOR]

Abstract Developing cost–benefit and high‐performance non‐noble metal oxygen reduction reaction (ORR) electrocatalysts is highly imperative for wide applications of renewable energy conversion devices. Herein, a one stone two birds phosphorization strategy has been proposed to synthesize hollow structured Cu/Cu3P heterogeneous nanoparticles supported on N, P co‐doped carbon (Cu/Cu3P@NP‐Cs). The optimized Cu/Cu3P@NP‐C‐900 features high ORR performance under both alkaline and acidic conditions. Moreover, the Cu/Cu3P@NP‐C‐900‐drivened Zn‐air battery exhibits a substantially higher power density output (148.2 mW cm−2) and stronger charge–discharge stability (300 h, 1805 cycles) than those of Pt/C‐equipped counterpart. The cross‐interface electron transfer from Cu3P to Cu effectively regulates the d‐band center of Cu/Cu3P, thereby leading to the balanced adsorption/desorption energy of oxygen species. Meanwhile, the hollow structure maximizes the exposure of accessible active centers, resulting in much accelerated ORR kinetics. This work proposes an innovative insight for developing hollow hetero‐structured catalysts to improve ORR performance.

Silica nanoparticles (SNPs) have shown promise in biomedical applications such as drug delivery and imaging due to their versatile synthetic methods, tunable physicochemical properties, and ability to load both hydrophilic and hydrophobic cargo with high efficiency. To improve the utility of these nanostructures, there is a need to control the degradation profile relative to specific microenvironments. The design of such nanostructures for controlled combination drug delivery would benefit from minimizing degradation and cargo release in circulation while increasing intracellular biodegradation. Herein, we fabricated two types of layer-by-layer hollow mesoporous SNPs (HMSNPs) containing two and three layers with variations in disulfide precursor ratios. These disulfide bonds are redox-sensitive, resulting in a controllable degradation profile relative to the number of disulfide bonds present. Particles were characterized for morphology, size and size distribution, atomic composition, pore structure, and surface area. No difference was observed between in vitro cytotoxicity profiles of the fabricated nanoparticles at 24 h in the concentration range below 100 µg mL−1. The degradation profiles of particles were evaluated in simulated body fluid in the presence of glutathione. The results demonstrate that the composition and number of layers influence degradation rates, and particles containing a higher number of disulfide bridges were more responsive to enzymatic degradation. These results indicate the potential utility of layer-by-layer HMSNPs for delivery applications where tunable degradation is desired. [ABSTRACT FROM AUTHOR]

The object of this paper is to generalize the notion of supplement in modules to monoid acts. In contrast to the case of modules that supplements of submodules do not generally exist, here we uniquely characterize the supplement of a proper subact of an act. Supplemented acts are defined as acts whose proper subacts all have proper supplements. We discuss how the property of being supplemented relates to certain other properties of acts. In particular, we prove that being supplemented and being completely reducible coincide. [ABSTRACT FROM AUTHOR]