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Keywords = double-shelled hollow structures

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21 pages, 14844 KiB  
Article
On the Design of Bionic Hierarchical H-Type Whip Restraints for Nuclear Power Plants
by Zheng He, Yuhang Yang, Libang Hu and Shuitao Gu
Appl. Sci. 2025, 15(10), 5507; https://doi.org/10.3390/app15105507 - 14 May 2025
Viewed by 391
Abstract
Whip restraints based on thin-walled structures are widely used for protection against high-energy pipe breaks in nuclear power plants due to their excellent impact resistance. Recently, biomimetic and hierarchical structures have emerged as focal points in thin-walled structure research, aimed at enhancing energy [...] Read more.
Whip restraints based on thin-walled structures are widely used for protection against high-energy pipe breaks in nuclear power plants due to their excellent impact resistance. Recently, biomimetic and hierarchical structures have emerged as focal points in thin-walled structure research, aimed at enhancing energy absorption capacities. Drawing inspiration from the nautilus shell and Fibonacci spiral, based on the nautilus bionic hierarchical multi-cell (NBHMC) structure, this study introduces a novel Nautilus Bionic Double Hierarchical Multi-Cell (NBDHMC) structure. Finite element analysis was employed to evaluate the energy absorption performance of the structure under axial and oblique loads using four crashworthiness parameters. Crashworthiness studies showed that the NBDHMC exhibits superior crashworthiness compared to the NBHMC and hollow circular tube configurations. Finally, the study investigated the influence of combination modes, hierarchical levels, cross-sectional characteristics, and other parameters on the parameterization of the NBDHMC. The results offer innovative insights for the design of highly efficient energy absorbers. Full article
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23 pages, 16092 KiB  
Article
Structural Performance and Failure Mechanisms in Bend Loading of Steel-Aerated Concrete Fire Wall Composite Panels
by Matthias Weiss, Xinyu Hu, Michael Pereira and Peng Zhang
Buildings 2025, 15(8), 1338; https://doi.org/10.3390/buildings15081338 - 17 Apr 2025
Viewed by 505
Abstract
Modularised wall panels are increasingly used in building and construction. A new double-skin composite (DSC) wall system technology uses clinch seams to combine two roll-formed open section profiles into a hollow steel shell that is then filled with a light-weight concrete foam and [...] Read more.
Modularised wall panels are increasingly used in building and construction. A new double-skin composite (DSC) wall system technology uses clinch seams to combine two roll-formed open section profiles into a hollow steel shell that is then filled with a light-weight concrete foam and can provide a fire-rated DSC solution for use in commercial and high-rise buildings. One important material parameter for the application is the panel performance in wind loading. This study presents a first fundamental analysis of the structural behaviour of the new DSC wall panel relevant to wind loading. For this, 3-point and 4-point bending tests combined with in situ camera analysis are performed and complimented with the analysis of seam strength and the concrete material parameters. The experimental results provide the first experimental evidence that the aerated concrete core material of the DSC panel only has a minor effect on the wall performance in bending. Most of the bending loads are absorbed by the tensile and compressive deformation of the steel outer shell and the shear deformation near the clinch seam. In this way, failure at maximum load is not initiated by concrete cracking but by steel sheet buckling or a mixed failure mode that combines steel buckling and seam opening. Full article
(This article belongs to the Special Issue Advances in Structural Techniques for Prefabricated Modular Buildings)
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23 pages, 7934 KiB  
Article
Investigation of Airborne Particulate Matter from a Holiday Celebration in Central Oklahoma Using an Unmanned Aerial Vehicle (UAV)
by John-Thomas Murray, Mark Lohatepanont, Fernando Sisniega Serrano, Diego Perez Avendano and Wilson Merchan-Merchan
Appl. Sci. 2025, 15(6), 3151; https://doi.org/10.3390/app15063151 - 14 Mar 2025
Cited by 1 | Viewed by 942
Abstract
Herein, a recently developed UAV/Drone approach as a new vector for the collection of airborne particulate matter is reported. In this study, airborne particle emissions from plumes generated in a holiday fireworks display were collected. A platform fabricated using a 3D printer was [...] Read more.
Herein, a recently developed UAV/Drone approach as a new vector for the collection of airborne particulate matter is reported. In this study, airborne particle emissions from plumes generated in a holiday fireworks display were collected. A platform fabricated using a 3D printer was mounted on the drone, which allowed for particulate capture using double-sided carbon tape attached to aluminum disks. The drone platform was used to trap airborne samples from two types of plumes: high-altitude sampling (HAS), which relates to professional fireworks, and low-altitude sampling (LAS), associated with personal fireworks. Collected samples were studied using a Scanning Electron Microscope alongside Electron Dispersal X-ray Spectroscopy (EDX) for elemental composition analysis. The overall findings regarding the physical morphology reveal several key observations. Firstly, particles from professional fireworks are significantly larger and more spheroidal than those from personal fireworks. Secondly, both types of fireworks show a consistent trend in which some of the larger particles have finer particulates deposited on their surfaces. Lastly, the plumes produced by both types contain spheres that are either solid, hollow or exhibit a core–shell structure. EDX analysis revealed the presence of various types of metals within the samples. EDX analysis shows that the samples collected from the HAS and LAS contain particulates with common elements. However, the samples from the plume of professional fireworks appear to have Ba, Mg, and Fe compared to the samples from personal fireworks. These elements are known to be used in powerful fireworks to create colored displays. A proposed mechanism for particulate growth in fireworks is proposed and discussed. Full article
(This article belongs to the Special Issue Air Quality Monitoring, Analysis and Modeling)
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14 pages, 109001 KiB  
Article
Construction and Regulation of Polymer@Silica Microspheres with Double-Shell Hollow Structures
by Mingxiu Jiang, Yuanyuan Yang, Jiawei Feng, Zhaopan Wang and Wei Deng
Molecules 2025, 30(4), 954; https://doi.org/10.3390/molecules30040954 - 18 Feb 2025
Cited by 1 | Viewed by 755
Abstract
Microspheres with well-defined hollow structures have been attracting interest due to their unique morphology and fascinating properties. Herein, a strategy for morphology and size control of hollow polymer@silica microspheres is proposed. Multilayer core–shell polymer microspheres, containing substantial carboxyl groups inside, evolve into microspheres [...] Read more.
Microspheres with well-defined hollow structures have been attracting interest due to their unique morphology and fascinating properties. Herein, a strategy for morphology and size control of hollow polymer@silica microspheres is proposed. Multilayer core–shell polymer microspheres, containing substantial carboxyl groups inside, evolve into microspheres with a 304 nm hollow structure after alkali treatment, which are used to construct hollow polymer@silica microspheres by coating the inorganic layer using the layer-by-layer (LBL) and sol–gel methods, respectively. The inorganic shell thickness of hollow polymer@silica microspheres can be adjusted from 15 nm to 33 nm by the self-assembled layers in the LBL method and from 15 nm to 63 nm by the dosage of precursor in the sol–gel method. Compared to the LBL method, the hollow polymer@silica microspheres prepared via the sol–gel method have a uniform and dense inorganic shell, thus ensuring the complete spherical morphology of the microspheres after calcination, even if the inorganic shell thickness is only 15 nm. Moreover, the hollow polymer@silica microspheres prepared via the sol–gel method exhibit improved compression resistance and good opacity, remaining intact at 16,000 psi and providing the corresponding coating with transmittance lower than 35.1%. This work highlights the morphology regulation of microspheres prepared by different methods and provides useful insights for the design of composites microspheres with controllable structures. Full article
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14 pages, 2851 KiB  
Communication
A MOF-Templated Double-Shelled Co3O4/NiCo2O4 Nanocomposite for Electrochemical Detection of Alfuzosin
by Al-Amin, Gajapaneni Venkata Prasad, Seung Joo Jang, Jeong-Wook Oh and Tae Hyun Kim
Nanomaterials 2024, 14(9), 757; https://doi.org/10.3390/nano14090757 - 25 Apr 2024
Cited by 5 | Viewed by 1906
Abstract
We developed a novel electrochemical sensor for the detection of alfuzosin (AFZ), a drug used to treat benign prostatic hyperplasia, using a double-shelled Co3O4/NiCo2O4 nanocomposite-modified electrode. The nanocomposites were synthesized using a template-assisted approach, with zeolitic [...] Read more.
We developed a novel electrochemical sensor for the detection of alfuzosin (AFZ), a drug used to treat benign prostatic hyperplasia, using a double-shelled Co3O4/NiCo2O4 nanocomposite-modified electrode. The nanocomposites were synthesized using a template-assisted approach, with zeolitic imidazole framework-67 (ZIF-67) as the sacrificial template, involving the formation of uniform ZIF-67/Ni-Co layered double hydroxide (LDH) hollow structures followed by calcination to achieve the final nanocomposite. The nanocomposite was characterized by various techniques and showed high porosity, large surface area, and good conductivity. The nanocomposite-modified electrode exhibited excellent electrocatalytic activity towards AFZ oxidation, with a wide linear range of 5–180 µM and a low limit of detection of 1.37 µM. The sensor also demonstrated good repeatability, reproducibility, and stability selectivity in the presence of common interfering substances. The sensor was successfully applied to determine the AFZ in pharmaceutical tablets and human serum samples, with satisfactory recoveries. Our results suggest that the double-shelled Co3O4/NiCo2O4 nanocomposite is a promising material for the fabrication of electrochemical sensors for AFZ detection. Full article
(This article belongs to the Special Issue Trends in Electrochemical Nanosensing)
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20 pages, 12075 KiB  
Article
A Novel Simplified FE Rail Vehicle Model in Longitudinal and Lateral Collisions
by Gongxun Deng, Yong Peng, Lin Hou, Zhixiang Li, Benhuai Li, Chao Yu and Ciaran Simms
Machines 2022, 10(12), 1214; https://doi.org/10.3390/machines10121214 - 14 Dec 2022
Cited by 7 | Viewed by 2994
Abstract
It is a challenge to efficiently and accurately predict train dynamic responses during complex collisions. In this paper, a novel numerical simplification method for high-speed rail vehicles during complex impact configurations is proposed. The central section of high-speed rail vehicles is a sandwich [...] Read more.
It is a challenge to efficiently and accurately predict train dynamic responses during complex collisions. In this paper, a novel numerical simplification method for high-speed rail vehicles during complex impact configurations is proposed. The central section of high-speed rail vehicles is a sandwich corrugated hollow double-shell structure. Starting with a baseline detailed finite element (FE) model of a high-speed train, the central section was first simplified as a solid single-shell structure. A parametric study with various simplification thickness ratios of the simplified FE rail vehicle model in different longitudinal rigid-wall collisions and lateral rigid-cylinder impacts was then performed using LS-DYNA. Furthermore, a correlation and analysis (CORA) objective rating method was used to evaluate the related responses between the simplified and detailed baseline FE rail vehicle models. The results demonstrate that the simplified FE model could effectively predict the rail vehicle impact responses. The displacement and impact force time histories of the simplified vehicle model with a thickness ratio of 0.38 matched closely with the results of the baseline detailed FE model under both longitudinal and lateral impacts (total combined CORA rating score: 93%). The rail vehicle impact deformations of the simplified vehicle model were similar to those of the baseline detailed model. The application of the simplified vehicle FE model substantially reduced the computational time (approximately 55% reduction). This work provides a solid basis for efficiently exploring train impact responses in complex collisions, and will be especially useful for train occupant injury assessment. Full article
(This article belongs to the Section Vehicle Engineering)
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21 pages, 5380 KiB  
Article
Construction of Double-Shelled Hollow Ag2S@Polydopamine Nanocomposites for Fluorescence-Guided, Dual Stimuli-Responsive Drug Delivery and Photothermal Therapy
by Minjie Gao, Zehua Han, Xu Zhang, Xueyan Zou, Lichao Peng, Yanbao Zhao and Lei Sun
Nanomaterials 2022, 12(12), 2068; https://doi.org/10.3390/nano12122068 - 15 Jun 2022
Cited by 26 | Viewed by 3120
Abstract
The design and preparation of multifunctional drug carriers for combined photothermal–chemotherapy of cancer have attracted extensive attention over the past few decades. However, the development of simple-structured stimuli-responsive theranostic agents as both photothermal agents and chemotherapeutic agents remains a big challenge. Herein, a [...] Read more.
The design and preparation of multifunctional drug carriers for combined photothermal–chemotherapy of cancer have attracted extensive attention over the past few decades. However, the development of simple-structured stimuli-responsive theranostic agents as both photothermal agents and chemotherapeutic agents remains a big challenge. Herein, a novel double-shelled nanocarrier composed of hollow Ag2S (HAg2S) nanospheres and a mesoporous polydopamine (MPDA) exterior shell was fabricated through a facile process. Notably, HAg2S possesses both fluorescence and photothermal properties. MPDA acts as a drug carrier and photothermal agent. Meanwhile, the cavity structure between HAg2S and MPDA provides more space for drug loading. The nanocarrier presents a high drug loading rate of 23.4%. It exhibits an apparent pH-responsive DOX release property due to the acidic sensitivity of PDA. In addition, the release of DOX is promoted under NIR irradiation, which is attributed to the heating action generated by the photothermal effect of HAg2S and MPDA. The cytotoxicity test shows that the nanocarriers possess good biocompatibility. Compared with single photothermal therapy or chemotherapy, the combined treatment represents a synergistic effect with higher therapeutic efficacy. In addition, the nanocarriers exhibit excellent fluorescence imaging capability and can target HepG2 cells. These simple-structured smart nanocarriers have a great potential for fluorescence-mediated combination cancer therapy. Full article
(This article belongs to the Section Biology and Medicines)
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12 pages, 7898 KiB  
Article
Non-Stacked γ-Fe2O3/C@TiO2 Double-Layer Hollow Nanoparticles for Enhanced Photocatalytic Applications under Visible Light
by Xun Sun, Xiao Yan, Huijuan Su, Libo Sun, Lijun Zhao, Junjie Shi, Zifan Wang, Jianrui Niu, Hengli Qian and Erhong Duan
Nanomaterials 2022, 12(2), 201; https://doi.org/10.3390/nano12020201 - 7 Jan 2022
Cited by 11 | Viewed by 2477
Abstract
Herein, a non-stacked γ-Fe2O3/C@TiO2 double-layer hollow nano photocatalyst has been developed with ultrathin nanosheets-assembled double shells for photodegradation phenol. High catalytic performance was found that the phenol could be completely degraded in 135 min under visible light, due [...] Read more.
Herein, a non-stacked γ-Fe2O3/C@TiO2 double-layer hollow nano photocatalyst has been developed with ultrathin nanosheets-assembled double shells for photodegradation phenol. High catalytic performance was found that the phenol could be completely degraded in 135 min under visible light, due to the moderate band edge position (VB at 0.59 eV and CB at −0.66 eV) of the non-stacked γ-Fe2O3/C@TiO2, which can expand the excitation wavelength range into the visible light region and produce a high concentration of free radicals (such as ·OH, ·O2−, holes). Furthermore, the interior of the hollow composite γ-Fe2O3 is responsible for charge generation, and the carbon matrix facilitates charge transfer to the external TiO2 shell. This overlap improved the selection/utilization efficiency, while the unique non-stacked double-layered structure inhibited initial charge recombination over the photocatalysts. This work provides new approaches for photocatalytic applications with γ-Fe2O3/C-based materials. Full article
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18 pages, 6368 KiB  
Article
Selective Recognition of Gallic Acid Using Hollow Magnetic Molecularly Imprinted Polymers with Double Imprinting Surfaces
by Jiawei Li, Xinji Zhou, Yu Yan, Dianling Shen, Danqing Lu, Yaping Guo, Lianwu Xie and Bin Deng
Polymers 2022, 14(1), 175; https://doi.org/10.3390/polym14010175 - 2 Jan 2022
Cited by 18 | Viewed by 2962
Abstract
Gallic acid is widely used in the field of food and medicine due to its diversified bioactivities. The extraction method with higher specificity and efficiency is the key to separate and purify gallic acid from complex biological matrix. Herein, using self-made core-shell magnetic [...] Read more.
Gallic acid is widely used in the field of food and medicine due to its diversified bioactivities. The extraction method with higher specificity and efficiency is the key to separate and purify gallic acid from complex biological matrix. Herein, using self-made core-shell magnetic molecularly imprinted polymers (MMIP) with gallic acid as template, a hollow magnetic molecularly imprinted polymer (HMMIP) with double imprinting/adsorption surfaces was prepared by etching the mesoporous silica intermediate layer of MMIP. The characterization and adsorption research showed that the HMMIP had larger specific surface area, higher magnetic response strength and a more stable structure, and the selectivity and saturated adsorption capacity (2.815 mmol/g at 318 K) of gallic acid on HMMIP were better than those of MMIP. Thus, in addition to MMIP, the improved HMMIP had excellent separation and purification ability to selectively extract gallic acid from complex matrix with higher specificity and efficiency. Full article
(This article belongs to the Section Polymer Analysis and Characterization)
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29 pages, 75295 KiB  
Article
Effect of Needle Type, Number of Layers on FPAFC Composite against Low-Velocity Projectile Impact
by Nandhu Prasad, Gunasekaran Murali, Sallal R. Abid, Nikolai Vatin, Roman Fediuk and Mugahed Amran
Buildings 2021, 11(12), 668; https://doi.org/10.3390/buildings11120668 - 20 Dec 2021
Cited by 17 | Viewed by 3612
Abstract
Protective structures subjected to intensive loads that may benefit from the use of multilayer composite structures with excellent hardness and impact resistance represent an emerging research field in recent times. In this study, low-velocity projectile impact tests were performed on Functionally-graded Preplaced Aggregate [...] Read more.
Protective structures subjected to intensive loads that may benefit from the use of multilayer composite structures with excellent hardness and impact resistance represent an emerging research field in recent times. In this study, low-velocity projectile impact tests were performed on Functionally-graded Preplaced Aggregate Fibrous Concrete (FPAFC) mixtures to evaluate their performance. The effects of projectile needle type, fibre type and hybridization in addition to the number of layers in the composites on projectile impact were investigated. The bioinspiration of the excellent impact strength of turtle shells was used to design an FPAFC comprising a higher amount of steel and polypropylene fibres at the outer layers. In parallel, one and two-layered concretes were also cast to assess the effectiveness of three-layered FPAFC. The tests were performed on disc specimens using non-deformable compound bevel, convex edge and hollow edge projectiles. The damage severity was quantified by the top damage area, bottom damage area and depth of penetration. In addition, a simple analytical model for predicting the composite mass expulsion was developed and implemented. Findings indicated that regardless of fiber type and distribution, the compound bevel projectile needle produced the lowest impact numbers for all single, double and triple-layer specimens compared to the convex edge and hollow edge projectiles. Repeated projectile impacts increased the penetration depth and damaged area at the top and bottom surfaces of all targets. Targets were more resistant to convex edge and hollow edge projectile penetration than the compound bevel. The experimental and analytical model results for mass expelled from the top surface are reasonably acceptable. This research gives an idea of developing advanced fibrous composite with superior impact resistance for the promising protective structures. Full article
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9 pages, 2259 KiB  
Article
Synthesis and Characteristics of Double-Shell Mesoporous Hollow Silica Nanomaterials to Improve CO2 Adsorption Performance
by Jong-tak Lee and Jae-Young Bae
Micromachines 2021, 12(11), 1424; https://doi.org/10.3390/mi12111424 - 19 Nov 2021
Cited by 7 | Viewed by 2649
Abstract
To improve the adsorption performance of carbon dioxide, which is considered the main culprit of greenhouse gases, the specific surface area and high pore volume of the adsorbing material should be considered. For a porous material, the performance of carbon dioxide adsorption is [...] Read more.
To improve the adsorption performance of carbon dioxide, which is considered the main culprit of greenhouse gases, the specific surface area and high pore volume of the adsorbing material should be considered. For a porous material, the performance of carbon dioxide adsorption is determined by the amine groups supporting capacity; the larger the pore volume, the greater the capacity to support the amine groups. In this study, a double-shell mesoporous hollow silica nanomaterial with excellent pore volume and therefore increased amine support capacity was synthesized. A core–shell structure capable of having a hollow shape was synthesized using polystyrene as a core material, and a double-shell mesoporous shape was synthesized by sequentially using two types of surfactants. The synthesized material was subjected to a sintering process of 600 degrees, and the N2 sorption analysis confirmed a specific surface area of 690 m2/g and a pore volume of 1.012 cm3/g. Thereafter, the amine compound was impregnated into the silica nanomaterial, and then, a carbon dioxide adsorption experiment was conducted, which confirmed that compared to the mesoporous hollow silica nanomaterial synthesized as a single shell, the adsorption performance was improved by about 1.36 times. Full article
(This article belongs to the Special Issue Nano Korea 2021)
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13 pages, 4681 KiB  
Article
Preparation and NH3 Gas-Sensing Properties of Double-Shelled Hollow ZnTiO3 Microrods
by Pi-Guey Su and Xiang-Hong Liu
Sensors 2020, 20(1), 46; https://doi.org/10.3390/s20010046 - 19 Dec 2019
Cited by 7 | Viewed by 2854
Abstract
A novel double-shelled hollow (DSH) structure of ZnTiO3 microrods was prepared by self-templating route with the assistance of poly(diallyldimethylammonium chloride) (PDDA) in an ethylene glycol (EG) solution, which was followed by calcining. Moreover, the NH3 gas-sensing properties of the DSH ZnTiO [...] Read more.
A novel double-shelled hollow (DSH) structure of ZnTiO3 microrods was prepared by self-templating route with the assistance of poly(diallyldimethylammonium chloride) (PDDA) in an ethylene glycol (EG) solution, which was followed by calcining. Moreover, the NH3 gas-sensing properties of the DSH ZnTiO3 microrods were studied at room temperature. The morphology and composition of DSH ZnTiO3 microrods films were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The formation process of double-shelled hollow microrods was discussed in detail. The comparative gas-sensing results revealed that the DSH ZnTiO3 microrods had a higher response to NH3 gas at room temperature than those of the TiO2 solid microrods and DSH ZnTiO3 microrods did in the dark. More importantly, the DSH ZnTiO3 microrods exhibited a strong response to low concentrations of NH3 gas at room temperature. Full article
(This article belongs to the Section Chemical Sensors)
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38 pages, 9323 KiB  
Review
Synthesis and Electrochemical Energy Storage Applications of Micro/Nanostructured Spherical Materials
by Qinghua Gong, Tingting Gao, Tingting Hu and Guowei Zhou
Nanomaterials 2019, 9(9), 1207; https://doi.org/10.3390/nano9091207 - 27 Aug 2019
Cited by 18 | Viewed by 5527
Abstract
Micro/nanostructured spherical materials have been widely explored for electrochemical energy storage due to their exceptional properties, which have also been summarized based on electrode type and material composition. The increased complexity of spherical structures has increased the feasibility of modulating their properties, thereby [...] Read more.
Micro/nanostructured spherical materials have been widely explored for electrochemical energy storage due to their exceptional properties, which have also been summarized based on electrode type and material composition. The increased complexity of spherical structures has increased the feasibility of modulating their properties, thereby improving their performance compared with simple spherical structures. This paper comprehensively reviews the synthesis and electrochemical energy storage applications of micro/nanostructured spherical materials. After a brief classification, the concepts and syntheses of micro/nanostructured spherical materials are described in detail, which include hollow, core-shelled, yolk-shelled, double-shelled, and multi-shelled spheres. We then introduce strategies classified into hard-, soft-, and self-templating methods for synthesis of these spherical structures, and also include the concepts of synthetic methodologies. Thereafter, we discuss their applications as electrode materials for lithium-ion batteries and supercapacitors, and sulfur hosts for lithium–sulfur batteries. The superiority of multi-shelled hollow micro/nanospheres for electrochemical energy storage applications is particularly summarized. Subsequently, we conclude this review by presenting the challenges, development, highlights, and future directions of the micro/nanostructured spherical materials for electrochemical energy storage. Full article
(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)
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12 pages, 3051 KiB  
Article
Synthesis of Double-Shelled Hollow Inorganic Nanospheres through Block Copolymer-Metal Coordination and Atomic Layer Deposition
by Nina Yan, Qingbao Guan, Zhiming Yang, Min Feng, Xizhi Jiang, Jun Liu and Lei Xu
Polymers 2019, 11(7), 1208; https://doi.org/10.3390/polym11071208 - 19 Jul 2019
Cited by 2 | Viewed by 3793
Abstract
Double-shelled hollow (DSH) structures with varied inorganic compositions are confirmed to have improved performances in diverse applications, especially in lithium ion battery. However, it is still of great challenge to obtain these complex nanostructures with traditional hard templates and solution-based route. Here we [...] Read more.
Double-shelled hollow (DSH) structures with varied inorganic compositions are confirmed to have improved performances in diverse applications, especially in lithium ion battery. However, it is still of great challenge to obtain these complex nanostructures with traditional hard templates and solution-based route. Here we report an innovative pathway for the preparation of the DSH nanospheres based on block copolymer self-assembly, metal–ligand coordination and atomic layer deposition. Polymeric composite micelles derived from amphiphilic block copolymers and ferric ions were prepared with heating-enabled micellization and metal–ligand coordination. The DSH nanospheres with Fe2O3 stands inner and TiO2 outer the structures can be obtained with atomic layer deposition of a thin layer of TiO2 followed with calcination in air. The coordination was carried out at room temperature and the deposition was performed at the low temperature of 80 °C, thus providing a feasible fabrication strategy for DSH structures without destruction of the templates. The cavity and the outer layer of the structures can also be simply tuned with the utilized block copolymers and the deposition cycles. These DSH inorganic nanospheres are expected to find vital applications in battery, catalysis, sensing and drug delivery, etc. Full article
(This article belongs to the Special Issue Self-assembly of Block Copolymers)
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15 pages, 9362 KiB  
Article
Self-Templating Synthesis of 3D Hierarchical NiCo2O4@NiO Nanocage from Hydrotalcites for Toluene Oxidation
by Dongdong Wang, Shuangde Li, Yingchao Du, Xiaofeng Wu and Yunfa Chen
Catalysts 2019, 9(4), 352; https://doi.org/10.3390/catal9040352 - 11 Apr 2019
Cited by 40 | Viewed by 6019
Abstract
Rational design LDHs (layered double hydroxides) with 3D hierarchical hollow structures have generated widespread interest for catalytic oxidation due to the high complexity in shell architecture and composition. Herein, we reported a handy two-step method to construct a 3D hierarchical NiCo2O [...] Read more.
Rational design LDHs (layered double hydroxides) with 3D hierarchical hollow structures have generated widespread interest for catalytic oxidation due to the high complexity in shell architecture and composition. Herein, we reported a handy two-step method to construct a 3D hierarchical NiCo2O4/NiO nanocage. This synthetic strategy contains a partial in situ transformation of ZIF-67 (zeolitic imidazolate framework-67) into Co-NiLDH yolk-shelled structures following ethanol etching, and a structure-preserved transformation from Co-NiLDH@ZIF-67 to a biphase nanocage following calcination. CoNi-yh-T (varied reaction time and calcination temperature) nanocages were investigated systematically by Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), H2- temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD) and studied for toluene oxidation. The CoNi-6h-350 sample showed much higher activity with 90% toluene conversion (T90) at 229 °C at a high space velocity (SV = 60,000 mL g−1 h−1) than other catalysts (T90 >240 °C). Abundant surface high valence Co ions caused by the novel hierarchical nanostructures, together with adsorbed oxygen species and abundant medium-strength surface acid sites, played a key role for catalytic activities. Full article
(This article belongs to the Special Issue Catalysis for the Removal of Gas-Phase Pollutants)
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