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Hollow carbon spheres and their noble metal-free hybrids in catalysis

《化学科学与工程前沿（英文）》 2021年 第15卷 第6期   页码 1380-1407 doi: 10.1007/s11705-021-2097-z

摘要： Hollow carbon spheres have garnered great interest owing to their high surface area, large surface-to-volume ratio and reduced transmission lengths. Herein, we overview hollow carbon sphere-based materials and their noble metal-free hybrids in catalysis. Firstly, we summarize the key fabrication techniques for various kinds of hollow carbon spheres, with a particular emphasis on controlling pore structure and surface morphology, and then heterogeneous doping as well as their metal-free/containing hybrids are presented; next, possible applications for non-noble metal/hollow carbon sphere hybrids in the area of energy-related catalysis, including oxygen reduction reaction, hydrogen evolution reaction, oxygen evolution reaction, water splitting, rechargeable Zn-air batteries and pollutant degradation are discussed; finally, we introduce the various challenges and opportunities offered by hollow carbon spheres from the perspective of synthesis and catalysis.

关键词： hollow carbon spheres     functionalization     noble metal-free     catalysis    

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Controllable Fe/HCS catalysts in the Fischer-Tropsch synthesis: Effects of crystallization time

Yifei Wang, Shouying Huang, Xinsheng Teng, Hongyu Wang, Jian Wang, Qiao Zhao, Yue Wang, Xinbin Ma

《化学科学与工程前沿（英文）》 2020年 第14卷 第5期   页码 802-812 doi: 10.1007/s11705-019-1866-4

摘要： The Fischer–Tropsch synthesis (FTS) continues to be an attractive alternative for producing a broad range of fuels and chemicals through the conversion of syngas (H and CO), which can be derived from various sources, such as coal, natural gas, and biomass. Among iron carbides, Fe C, as an active phase, has barely been studied due to its thermodynamic instability. Here, we fabricated a series of Fe C embedded in hollow carbon sphere (HCS) catalysts. By varying the crystallization time, the shell thickness of the HCS was manipulated, which significantly influenced the catalytic performance in the FTS. To investigate the relationship between the geometric structure of the HCS and the physic-chemical properties of Fe species, transmission electron microscopy, X-ray diffraction, N physical adsorption, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction, Raman spectroscopy, and Mössbauer spectroscopy techniques were employed to characterize the catalysts before and after the reaction. Evidently, a suitable thickness of the carbon layer was beneficial for enhancing the catalytic activity in the FTS due to its high porosity, appropriate electronic environment, and relatively high Fe C content.

关键词： Fischer–Tropsch synthesis     Fe-based catalyst     Fe2C     hollow carbon sphere     crystallization time    

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Novel method of constructing generalized Hoberman sphere mechanisms based on deployment axes

Xuemin SUN, Yan-An YAO, Ruiming LI

《机械工程前沿（英文）》 2020年 第15卷 第1期   页码 89-99 doi: 10.1007/s11465-019-0567-5

摘要： This study proposes a method of constructing type II generalized angulated elements (GAEs II) Hoberman sphere mechanisms on the basis of deployment axes that intersect at one point. First, the constraint conditions for inserting GAEs II into deployment axes to form a loop are given. The angle constraint conditions of the deployment axes are obtained through a series of linear equations. Second, the connection conditions of two GAEs II loops that share a common deployable center are discussed. Third, a flowchart of constructing the generalized Hoberman sphere mechanism on the basis of deployment axes is provided. Finally, four generalized Hoberman sphere mechanisms based on a fully enclosed regular hexahedron, arithmetic sequence axes, orthonormal arithmetic sequence axes, and spiral-like axes are constructed in accordance with the given arrangement of deployment axes that satisfy the constraint conditions to verify the feasibility of the proposed method.

关键词： deployable mechanism     type II generalized angulated elements     Hoberman sphere mechanism     deployment axes     constraint conditions    

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用于储能设备的一种新型高导电性和高选择性质子交换膜 Article

Kang Huang, Shuhao Lin, Yu Xia, Yongsheng Xia, Feiyan Mu, Yuqin Lu, Hongyan Cao, Yixing Wang, Weihong Xing, Zhi Xu

《工程（英文）》 2023年 第28卷 第9期   页码 69-78 doi: 10.1016/j.eng.2022.11.008

摘要：

Ion conductive membranes (ICMs) with highly conductive proton selectivity are of significant importance and greatly desired for energy storage devices. However, it is extremely challenging to construct fast proton-selective transport channels in ICMs. Herein, a membrane with highly conductive proton selectivity was fabricated by incorporating porous carbon sieving nanospheres with a hollow structure (HCSNs) in a polymer matrix. Due to the precise ion sieving ability of the microporous carbon shells and the fast proton transport through their accessible internal cavities, this advanced membrane presented a proton conductivity (0.084 S·cm−1) superior to those of a commercial Nafion 212 (N212) membrane (0.033 S·cm−1) and a pure polymer membrane (0.049 S·cm−1). The corresponding proton selectivity of the membrane (6.68 × 105 S·min·cm−3) was found to be enhanced by about 5.9-fold and 4.3-fold, respectively, compared with those of the N212 membrane (1.13 × 105 S·min·cm−3) and the pure membrane (1.56 × 105 S·min·cm−3). Low-field nuclear magnetic resonance (LF-NMR) clearly revealed the fast proton-selective transport channels enabled by the HCSNs in the polymeric membrane. The proposed membrane exhibited an outstanding energy efficiency (EE) of 84% and long-term stability over 1400 cycles with a 0.065% capacity decay per cycle at 120 mA·cm−2 in a typical vanadium flow battery (VFB) system.

关键词： Ion conductive membrane     Hollow carbon sieving nanosphere     Proton transport channel     Flow battery    

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Nanostructured hollow spheres of hydroxyapatite: preparation and potential application in drug delivery

Xiaojing ZHANG, Weixin ZHANG, Zeheng YANG, Zhao ZHANG

《化学科学与工程前沿（英文）》 2012年 第6卷 第3期   页码 246-252 doi: 10.1007/s11705-012-1299-9

摘要： A solvothermal method has been successfully used to prepare nanostructured hydroxyapatite (HA) hollow spheres with average diameters of about 500 nm and shell thicknesses of about 100 nm in a glycerin/water mixed solvent. Transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FESEM) images show that the shells of the HA hollow spheres are actually composed of nanosheets with thicknesses of about 10 nm. By tuning the glycerin/water volume ratio, two other kinds of HA solid spheres with average diameters of about 6 or 20 μm were assembled from nanoflakes. The properties of the different kinds of spheres as drug delivery carriers were evaluated. Ibuprofen (IBU) was chosen as the model drug to load into the HA samples. The nanostructured HA samples showed a slow and sustained release of IBU. The HA hollow spheres exhibited a higher drug loading capacity and more favorable release properties than the HA solid spheres and thus are very promising for controlled drug release applications.

关键词： hydroxyapatite     hollow spheres     synthesis     drug release    

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Seismic performance of precast hollow bridge piers with different construction details

Zhiqiang WANG,Jiping GE,Hongyi WEI

《结构与土木工程前沿（英文）》 2014年 第8卷 第4期   页码 399-413 doi: 10.1007/s11709-014-0273-7

摘要： Currently the design scheme of precast hollow concrete bridge piers will be adopted in bridge design in China, but there is no code including specific design details of precast segmental piers in high seismic risk area. For comparative study of seismic performance of the hollow bridge piers which had different design details, six specimens of hollow section bridge pier were designed and tested. The specimens consist of the monolithic cast-in-place concrete bridge pier, precast segmental prestressed pier with cast-in-place joint and precast segmental concrete bridge pier with dry joints. Results show that all specimens have good displacement capacity. The bridge pier with bonded prestressed strands exhibits better energy dissipation capacity and higher strength. The un-bonded prestressed strand bridge pier displays less residual plastic displacement and energy dissipation capacity. The bridge pier with both bonded prestressed strands at the edge of the section and un-bonded in the center of the section not only exhibits more ductility capacity and less residual plastic displacement, but also shows better energy dissipation capacity. Compared with experimental results of prestressed bridge columns, analytical result demonstrates the developed numerical analysis model would provide the reasonable and accurate results.

关键词： hollow pier     seismic performance     cyclic load     precast concrete     bridge columns    

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Impingement of hollow cone spray on hot porous medium

ZHAO Zhiguo, XIE Maozhao

《能源前沿（英文）》 2008年 第2卷 第3期   页码 273-278 doi: 10.1007/s11708-008-0048-8

摘要： To have a good understanding of the formation of homogenous mixture in a porous medium engine, the interaction between hollow cone spray and hot porous medium was studied numerically by using an improved version of KIVA-3V code. The improved KIVA-3V code is incorporated with an impingement model, heat transfer model and linearized instability sheet atomization (LISA) model to simulate the hollow cone spray. The reasonability of the impingement model and heat transfer model was validated. With a simple model to describe the structure of the porous medium, the interaction between hollow cone spray and hot porous medium was simulated under different ambient pressures and spray cone angles. Computational results show that the fuel spray could be divided into smaller ones, which provides conditions for the quick evaporation of fuel droplets and the mixing of fuel vapor with air. Differences in ambient pressure and spray cone angle affect the distribution of droplets in the porous medium.

关键词： improved version     simple     impingement     atomization     hollow    

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Preparation and characterization of EVAL hollow fiber membrane adsorbents filled with cation exchange

Fengli ZHANG, Yuzhong ZHANG, Hong LI, Guangfen LI,

《化学科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 462-467 doi: 10.1007/s11705-009-0011-1

摘要： EVAL hollow fiber membrane adsorbents filled with powder D061-type cation exchange resin were prepared through dry-wet spinning process, using hydrophilic copolymer EVAL as the fiber substrate. The microstructures of the membrane adsorbents were observed, and the pure water fluxes, BSA rejection, and static adsorption capacities of membrane adsorbents for BSA were measured. The effect of the resin-filled content on membrane performance has been discussed. The results showed that EVAL hollow fiber membrane adsorbents filled with D061-type cation exchange resins had good adsorption capacity, and the adsorption capacity increased with the quantity of the resin-filled content. The static protein adsorption capacity was 77.14 mg BSA/g membrane adsorbents when D061 resin loading content was 65% at pH 4.5.

关键词： substrate     copolymer EVAL     exchange     EVAL hollow     resin-filled content    

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High velocity impact of metal sphere on thin metallic plate using smooth particle hydrodynamics (SPH)

Hossein ASADI KALAMEH, Arash KARAMALI, Cosmin ANITESCU, Timon RABCZUK

《结构与土木工程前沿（英文）》 2012年 第6卷 第2期   页码 101-110 doi: 10.1007/s11709-012-0160-z

摘要： The modeling of high velocity impact is an important topic in impact engineering. Due to various constraints, experimental data are extremely limited. Therefore, detailed numerical simulation can be considered as a desirable alternative. However, the physical processes involved in the impact are very sophisticated; hence a practical and complete reproduction of the phenomena involves complicated numerical models. In this paper, we present a smoothed particle hydrodynamics (SPH) method to model two-dimensional impact of metal sphere on thin metallic plate. The simulations are applied to different materials (Aluminum, Lead and Steel); however the target and projectile are formed of similar metals. A wide range of velocities (300, 1000, 2000, and 3100 m/s) are considered in this study. The goal is to study the most sensitive input parameters (impact velocity and plate thickness) on the longitudinal extension of the projectile, penetration depth and damage crater.

关键词： smoothed particle hydrodynamics     high velocity impact     sensitivity analysis    

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Preparation and characterization of alumina hollow fiber membranes

Tao WANG, Yuzhong ZHANG, Guangfen LI, Hong LI

《化学科学与工程前沿（英文）》 2009年 第3卷 第3期   页码 265-271 doi: 10.1007/s11705-009-0010-2

摘要： With the rapid development of membrane technology in water treatment, there is a growing demand for membrane products with high performance. The inorganic hollow fiber membranes are of great interest due to their high resistance to abrasion, chemical/thermal degradation, and higher surface area/volume ratio therefore they can be utilized in the fields of water treatment. In this study, the alumina (Al O ) hollow fiber membranes were prepared by a combined phase-inversion and sintering method. The organic binder solution (dope) containing suspended Al O powders was spun to a hollow fiber precursor, which was then sintered at elevated temperatures in order to obtain the Al O hollow fiber membrane. The dope solution consisted of polyethersulfone (PES), N-methyl-2-pyrrolidone (NMP) and polyvinylpyrrolidone (PVP), which were used as polymer binder, solvent and additive, respectively. The prepared Al O hollow fiber membranes were characterized by a scanning electron microscope (SEM) and thermal gravimetric analysis (TG). The effects of the sintering temperature and Al O /PES ratios on the morphological structure, pure water flux, pore size and porosity of the membranes were also investigated extensively. The results showed that the pure water flux, maximum pore size and porosity of the prepared membranes decreased with the increase in Al O /PES ratios and sintering temperature. When the Al O /PES ratio reached 9, the pure water flux and maximum pore size were at 2547 L/m ·h and 1.4 μm, respectively. Under 1600°C of sintering temperature, the pure water flux and maximum pore size reached 2398 L/(m ·h) and 2.3 μm, respectively. The results showed that the alumina hollow fiber membranes we prepared were suitable for the microfiltration process. The morphology investigation also revealed that the prepared Al O hollow fiber membrane retained its’asymmetric structure even after the sintering process.

关键词： Al2O3     ceramic membranes     hollow fiber    

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Applications of hollow nanomaterials in environmental remediation and monitoring: A review

Yuankai ZHANG,Zhijiang HE,Hongchen WANG,Lu QI,Guohua LIU,Xiaojun ZHANG

《环境科学与工程前沿（英文）》 2015年 第9卷 第5期   页码 770-783 doi: 10.1007/s11783-015-0811-0

摘要： Hollow nanomaterials have attracted significant attention because of their high chemical and thermal stability, high specific surface area, high porosity, low density, and good biocompatibility. These state-of-the-art nanomaterials have been shown to efficiently adsorb heavy metals, and volatile hazardous substances, photodegrade persistent organic pollutants, and other compounds, and inactivate bacteria. Such properties have enabled the use of these materials for environmental remediation, such as in water/wastewater treatment, soil remediation, air purification, and substance monitoring, etc. Hollow nanomaterials showed higher photocatalytic activity than those without hollow structure owing to their high active surface area, reduced diffusion resistance, and improved accessibility. And, the Doping method could improve the photocatalytic performance of hollow nanomaterials further under visible light. Moreover, the synthetic mechanisms and methods of these materials are important because their size and morphology help to determine their precise properties. This article reviews the environmental applications and potential risks of these materials, in addition to their syntheses. Finally, an outlook into the development of these materials is provided.

关键词： hollow nanomaterials     environmental remediation     nanotechnology     nanostructures     morphology    

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Hot-dip galvanizing of cold-formed steel hollow sections: a state-of-the-art review

Min SUN, Jeffrey A. PACKER

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 49-65 doi: 10.1007/s11709-017-0448-0

摘要： A good understanding of the effects of galvanizing on the short- and long-term behaviours of steel components is essential for structural design. This review paper is motivated by a series of recent reports on cracking in galvanized cold-formed tubular steel structures and the limitations of current steel product standards and steel design specifications in this field. The steel-related and galvanizing-related factors, different pre-galvanizing countermeasures for brittle cracking and the available technical documents are summarized. An extensive bibliography is provided as a basis for future research and development in this field.

关键词： cold-formed steel     hollow structural sections     hot-dip galvanizing     embrittlement     heat-treatment     residual stress     cracking    

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Ag/PMMA hollow waveguide for solar energy transmission

He LAN, Jianjun HAN, Hongping CHEN, Xiujian ZHAO

《化学科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 303-307 doi: 10.1007/s11705-010-0565-y

摘要： This paper describes an elaborate study on obtaining Ag/PMMA (polymethyl methacrylate) leaky hollow waveguide which has a large aperture and low loss in transmitting solar energy. Through analyses and comparison, a quartz capillary with the inner diameter of 2 mm was chosen as hollow waveguide. We used the xenon light source, which has the similar spectrum as the sunlight to test and analyze the performance of the Ag/PMMA leakage hollow waveguide. The results are consistent with the transmitted theory of the dielectric/metal leaky type well. Meanwhile, the Ag/PMMA leaky-type hollow waveguide in this work had good qualities. Therefore, it will be a satisfactory medium for solar energy transmission.

关键词： hollow waveguide     transmit the solar energy     Ag/PMMA multiple film     parabolic collector    

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Formation of CaCO hollow microspheres in carbonated distiller waste from Solvay soda ash plants

《化学科学与工程前沿（英文）》   页码 1659-1671 doi: 10.1007/s11705-022-2173-z

摘要： For decades, distiller waste and CO2 were not the first choice for production of high valued products. Here, CaCO3 hollow microspheres, a high-value product was synthesized from such a reaction system. The synthetic methods, the formation mechanism and operational cost were discussed. When 2.5 L·min–1·L–1 CO2 was flowed into distiller waste (pH = 11.4), spheres with 4–13 μm diameters and about 2 μm shell thickness were obtained. It is found that there is a transformation of CaCO3 particles from solid-cubic nuclei to hollow spheres. Firstly, the Ca(OH)2 in the distiller waste stimulated the nucleation of calcite with a non-template effect and further maintained the calcite form and prevented the formation of vaterite. Therefore, in absence of auxiliaries, the formation of hollow structures mainly depended on the growth and aging of CaCO3. Studies on the crystal morphology and its changes during the growth process point to the inside–out Ostwald effect in the formation of hollow spheres. Change in chemical properties of the bulk solution caused changes in interfacial tension and interfacial energy, which promoted the morphological transformation of CaCO3 particles from cubic calcite to spherical clusters. Finally, the flow process for absorption of CO2 by distiller waste was designed and found profitable.

关键词： distiller waste     CO2     hollow microsphere     CaCO3     Ca(OH)2     inside−out Ostwald effect    

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Effects of baffles on separation of aqueous ethanol solution with hollow fibers

Zhihong YANG, Guoliang ZHANG, Lan LIN, Danping REN, Qin MENG, Hongzi ZHANG

《化学科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 68-72 doi: 10.1007/s11705-009-0130-8

摘要： The effects of baffles on the operation and mass-transfer characteristics in novel hollow fiber membrane contactor used in distillation were investigated. Hollow fiber membranes, coated with a 7 μm polydimethyl-siloxane, were operated as structural packing in the separation of ethanol-water solutions. The parallel flow mode was chosen for separation due to the stronger driving force of the concentration difference, in which liquid flows through the lumens of the fibers and vapor flows countercurrent-wise outside the fibers. Two baffles were installed on the shell side of the membrane contactors to enhance separation, which had a round shape with a semi-lunar hole. The results show that both baffled and unbaffled membrane contactors gave better, more productive separations than traditional packing in distillation, such as the excellent Sulzer Gauze BX structured packing. The baffled membrane contactors performed better than unbaffled ones, especially at high vapor velocities. The minimal HTU of membrane contactor with baffles could reach as low as 4.5 cm, and almost all the contactors could work well above the limit where flooding normally occurs in conventional cases. Theoretical analysis predicted that baffles helped membrane module to obtain a higher mass-transfer coefficient and a smaller mass-transfer resistance. Finally, theoretical mass-transfer coefficient and experimental value were compared as well as the contribution of each individual mass-transfer coefficients among liquid, gas and membrane.

关键词： hollow fiber     membrane contactor     baffle     mass-transfer     ethanol-water    

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标题 作者 时间 类型 操作

Hollow carbon spheres and their noble metal-free hybrids in catalysis

期刊论文

Controllable Fe/HCS catalysts in the Fischer-Tropsch synthesis: Effects of crystallization time

Yifei Wang, Shouying Huang, Xinsheng Teng, Hongyu Wang, Jian Wang, Qiao Zhao, Yue Wang, Xinbin Ma

期刊论文

Novel method of constructing generalized Hoberman sphere mechanisms based on deployment axes

Xuemin SUN, Yan-An YAO, Ruiming LI

期刊论文

用于储能设备的一种新型高导电性和高选择性质子交换膜

Kang Huang, Shuhao Lin, Yu Xia, Yongsheng Xia, Feiyan Mu, Yuqin Lu, Hongyan Cao, Yixing Wang, Weihong Xing, Zhi Xu

期刊论文

Nanostructured hollow spheres of hydroxyapatite: preparation and potential application in drug delivery

Xiaojing ZHANG, Weixin ZHANG, Zeheng YANG, Zhao ZHANG

期刊论文

Seismic performance of precast hollow bridge piers with different construction details

Zhiqiang WANG,Jiping GE,Hongyi WEI

期刊论文

Impingement of hollow cone spray on hot porous medium

ZHAO Zhiguo, XIE Maozhao

期刊论文

Preparation and characterization of EVAL hollow fiber membrane adsorbents filled with cation exchange

Fengli ZHANG, Yuzhong ZHANG, Hong LI, Guangfen LI,

期刊论文

High velocity impact of metal sphere on thin metallic plate using smooth particle hydrodynamics (SPH)

Hossein ASADI KALAMEH, Arash KARAMALI, Cosmin ANITESCU, Timon RABCZUK

期刊论文

Preparation and characterization of alumina hollow fiber membranes

Tao WANG, Yuzhong ZHANG, Guangfen LI, Hong LI

期刊论文

Applications of hollow nanomaterials in environmental remediation and monitoring: A review

Yuankai ZHANG,Zhijiang HE,Hongchen WANG,Lu QI,Guohua LIU,Xiaojun ZHANG

期刊论文

Hot-dip galvanizing of cold-formed steel hollow sections: a state-of-the-art review

Min SUN, Jeffrey A. PACKER

期刊论文

Ag/PMMA hollow waveguide for solar energy transmission

He LAN, Jianjun HAN, Hongping CHEN, Xiujian ZHAO

期刊论文

Formation of CaCO hollow microspheres in carbonated distiller waste from Solvay soda ash plants

期刊论文

Effects of baffles on separation of aqueous ethanol solution with hollow fibers

Zhihong YANG, Guoliang ZHANG, Lan LIN, Danping REN, Qin MENG, Hongzi ZHANG

期刊论文