A nest-like hierarchical porous V2O5 as a high-performance cathode material for Li-ion batteries

In this article, V₂O₅ with a novel nest-like hierarchical porous structure has been synthesized by a facile solvothermal method and investigated as cathode material for lithium-ion batteries. The nest-like V₂O₅ with a diameter of about 1.5 µm, was composed of interconnected nanosheets with a highly porous structure. Without other modification, the as-prepared V₂O₅ electrode exhibited superior capacity. An initial discharge capacity of 330 mAh g⁻¹ (at a current density of 100 mA g⁻¹) could be delivered and a stable discharge capacity of 240 mAh g⁻¹ after 50 cycles is maintained. The excellent performance was attributed to the hierarchical porous structure that could buffer against the local volume change and shorten the lithium-ions diffusion distance.     

我国能源形势分析及其解决对策

随着中国社会经济的持续、快速发展,中国能源面临着日益严峻的形势和挑战,即能源供需矛盾加剧、能源利用效率低和能源结构不合理。为了解决中国能源的问题,本文提出了通过利用国内外两种资源、两个市场增加我国能源产量;调整产业结构实现节能;利用先进技术,在工业、建筑和交通三大领域提高能源利用效率;大力引进石油天然气,积极发展可再生能源和新能源,实现能源结构的“优化”等对策。     

Ultra-high specific capacitance of self-doped 3D hierarchical porous turtle shell-derived activated carbon for high-performance supercapacitors

The turtle shell of biomass waste is used as raw material, and the natural inorganic salt contained in it is used as a salt template in combination with a chemical activation method to successfully prepare a high-performance activated carbon with hierarchical porous structure. The role of hydroxyapatite (HAP) and KOH in different stages of preparation was investigated. The prepared turtle shell-derived activated carbon (TSHC-5) has a well-developed honeycomb pore structure, which gives it a high specific surface area (SSA) of 2828 m² g^?1 with a pore volume of 1.91 cm³ g^?1. The excellent hierarchical porous structure and high heteroatom content (O 6.88%, N 5.64%) allow it to have an ultra-high specific capacitance of 727.9 F g^?1 at 0.5 A g^?1 with 92.27% of capacitance retention even after 10,000 cycles. Excitingly, the symmetric supercapacitor assembled from TSHC-5 activated carbon exhibits excellent energy density and cycling stability in a 1 M Na₂SO₄ aqueous solution. The energy density is 45.1 Wh·kg^?1 at a power density of 450 W kg^?1, with 92.05% capacitance retention after 10,000 cycles. Therefore, turtle shell-derived activated carbon is extremely competitive in sustainable new green supercapacitor electrode materials.     

Compression strength and fracture mechanism of a hierarchical porous yttria-stabilized zirconia microsphere prepared using electro-spraying associated with phase inversion technique

The compression strength and breakage mechanism of a hierarchical porous sphere in hundred-micron size were investigated in the present work. 3 mol% yttria-stabilized zirconia (YSZ) microspheres were prepared by electro-spraying associated with phase inversion (ES-PI) technique. The characteristic compression strengths of the ES-PI microspheres were measured by quasi-static uniaxial compression test, which increased from 19 MPa to 155 MPa as the sintering temperature increased from 1100 °C to 1400 °C. With the similar porosity, the compression strength of the hierarchical structure microsphere was almost three times higher than that of the hollow microsphere. Further, the breakage mechanism of the ES-PI microspheres was proposed by the honeycomb model of cellular materials, which suggested that the breakage of the ES-PI microsphere initiated from the elastic instability of the walls around the finger-like pores. These findings can help the mechanical performance optimization for ceramic microspheres with lightweight structure.     

聚氨酯多孔膜的结构和透湿性能研究

研究了湿法涂层技术制备聚氨酯(PU)多孔膜的工艺条件以及致孔剂含量对多孔膜微孔结构和透湿性能的影响。致孔剂的加入可以增大多孔膜的孔径。多孔膜的表面(与水的接触面)孔径为10μm～20／μm，而底面(与基材的接触面)孔径为60／μm～100／μm。断面结构显示，多孔膜的内部疏松多孔，孔与孔之间相互连通。进一步探讨了溶液的成膜过程和多孔膜的透湿机理。     

闭孔泡沫陶瓷的研究现状及应用前景

闭孔泡沫陶瓷由于结合了陶瓷材料自身的优异性能以及其特殊的多孔结构,从而具有良好的保温、绝热、隔音、耐腐蚀、防水等性能,可作为复合功能材料在建筑领域中应用,对环境保护、能源节约具有重要的意义,已得到了行业,科研机构的广泛关注。文章介绍了闭孔泡沫陶瓷的国内外研究现状,对其在制备工艺、成果推广等方面存在的问题进行了分析,对其应用前景进行了展望。     

Ceramic foams with micron/sub-micron sized porous structure for efficient high-temperature particulate matter capture

Constructing high-performance air filters for high-temperature particulate matter (PM) removal is of great importance but remains challenging. Here we demonstrate the ceramic foam-based filters via polyurethane (PU) foaming using diatomite and kaolin powder as the starting materials. Diatomite was grafted by dodecanedioic acid (DA) to improve the dispersity in the PU slurry. The calcined products demonstrated a hierarchical pore structure with multiple well-controlled micron-sized window pores on the cell wall of the sub-micron bubble. The resulting products exhibited a high removal efficiency (96.3%) at a pressure drop of 33 Pa. This research showed that as-prepared ceramic foams can be potentially used as new high-temperature filters for high-temperature PM removal.     

Hierarchically Fe-doped porous carbon derived from phenolic resin for high performance supercapacitor

Supercapacitors are promising for high power application in the recent years. In particular, the conversion of simple and available carbon materials into economic and high performance electrical devices receives excellent scientific and technological interest. This paper reports a one-step strategy for synthesizing hierarchical porous carbon derived from phenolic resin (PR), which is then used to configure electric double-layer capacitors (EDLCs). Here, a carbon material with a flexible porous structure, large specific surface area, and high graphitization degree is prepared using potassium ferrate (K₂FeO₄) to catalytically activate PR and to realize synchronous carbonization and graphitization. This method overcomes the disadvantage of time-consuming, high-cost, and environmentally unfriendly. In addition, the as-prepared carbon material has a high specific surface area (1086 m² g^?1) and a large pore size (3.07 nm), which can increase the transfer rate of electrolyte ions. The specific capacitance of the obtained electrode material is 315 F g^?1 at 1.0 A g^?1, and the optimized electrode material has an ultra-long cycle lifetime (capacitance retention rate is 96.3% after 10,000 cycles). Thus, the hierarchically Fe-doped porous carbon material derived from PR material is expected to realize high rate capacitance for supercapacitor applications.     

Enhanced NO2 detection using hierarchical porous ZnO nanoflowers modified with graphene

Because of their potential applications in gas sensing and catalysis, reduced graphene oxide (RGO) and ZnO have been the focus of much recent attention. However, few reported materials have been produced via the combination of hierarchical ZnO structures with RGO to achieve high sensing performances. In this paper, a hydrothermal method was used to synthesize hierarchical porous ZnO nanoflowers, which were then combined with graphene to enhance their sensing performances. The rapid detection of 1 ppm NO₂ was achieved at 174 °C. The morphologies and structures of these materials were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. Photoluminescence measurements and X-ray photoelectron spectroscopy were also used to investigate the mechanism of gas sensing by these materials.     

Direct ink writing of porous SiC ceramics with geopolymer as binder

We herein report a novel strategy for direct ink writing of porous SiC parts by using geopolymers (GP) as binders and sintering SiC/GP composites at high temperatures via carbothermal reduction. The effects of treatment temperatures on the microstructure, pore size distribution and compressive strength of SiC/GP composites were systematically investigated. The total porosity of porous SiC carriers was as high as 76.4 vol% after being sintered at 1800 °C and exhibited a much broader pore size distribution (pore volumes) between 39 nm and 13.951 µm (~1.68 mL/g) accompanied by an interconnected hierarchical porous structure. After loading lamellar graphene oxide into the porous SiC carrier to form GO/SiC adsorbents, they exhibited fast and near-unity removal of methylene blue, and the adsorption efficiency still exceeded 82.0% after multiple times usage. These results prove that it is possible to remove hazardous materials from wastewater using reusable porous SiC ceramics as reusable adsorbent carriers.     

新形势下的节能降耗工作

新形势下各级政府要加强宣传,提高全社会对节能降耗工作的认识。化工行业应完善节能法规建设,组织和培育节能技术和产品市场,搞好节能监测工作,推进技术进步。     

The influence of structure order on the kinetics of dehydroxylation of kaolinite

The structural order of kaolinite is an important factor that shows a substantial effect on the processes which take place during the thermal treatment of kaolin. The influence of structural order on the dehydroxylation process was investigated by simultaneous thermogravimetry and differential thermal analysis (TG-DTA). The thermal analysis was performed on the samples with gradually decreasing structural order prepared by milling procedure. The apparent activation energy of dehydroxylation process decreases with decreasing structural order according to the exponential function. The extrapolation of experimental data leads to the estimation of apparent activation energy of 76.6 kJ mol^?1 and of frequency factor of 0.12 × 10⁴ s^?1 related to completely disordered form of kaolinite, while the ordered form shows the apparent activation energy of 216.17 kJ mol^?1 and the frequency factor of 9.26 × 10⁴ s^?1. The relationships between features such as the infrared pattern of treated material, the degree of structural order and the apparent activation energy were established.     

Alkalische Aktivierung und Reaktivierung von Sekundärrohstoffen der Bau- und Abbruchindustrie

The present work deals with the production of geopolymers from brick flour and mixed rubble using an alkaline activator solution. The study aims to investigate whether these geopolymers can be reactivated several times without having to add new starting material, and how the number of reactivations affects the structure and material properties. The results show that geopolymers can be made from a mixture of brick flour and mixed rubble and can be ground up and reactivated up to three times.     

Gradually anchoring sulfur into in-situ doped carbon substrate as cathode for Li–S batteries with excellent wide-temperature performance

Carbon spheres, prepared by hydrothermally treating fresh potato starch, is employed as the sulfur host to configure a high-performance cathode substrate candidate for Li–S batteries. As confirmed by experimental results, both the improved the rate and cycle performances of Li–S batteries cathode with gradient sulfur immobilization, are mainly attributed to the confining, adsorption and conduction multi-functions of as-prepared carbon spheres toward polysulfides. Specifically, on starting the discharging/charging cycles, the active material α-S₈ is irreversibly converted to polysulfides and then transformed between β-S₈ and polysulfides during the next charge/discharge cycles. After initialization at 0.1C for 3 cycles, the initial reversible discharge capacities of the Li–S batteries cathode with optimized sulfur amount are 1072.5, 831.3, 780.4, 726.8, 714.3, 702.7 mAh g^?1_sulfur at 0.1, 0.5, 1, 2, 3 and 4 C, which is superior to those of the most previously reported reports. Besides that, as-designed potato-derived carbon based composite cathodes exhibits remarkable rate performance and cycling stability even at wide temperature ranging from ?40 to 60 °C, which evidently supports the dominant role of as-prepared 3D carbon spheres in boosting the cathode performance for Li–S batteries.     

Synthesis of hierarchical porous silicas with a controlled pore size distribution at various length scales

Hierarchically structured porous materials are of great interest to catalysis, where an accurately controlled pore texture at different length scales can help to reduce or otherwise control transport limitations. A method is presented to synthesize bimodal structured silicas, with an independently controlled small meso- and large meso-to macroporosity. Small primary MCM-41 particles assemble around micelles formed by a tri-block copolymer surfactant that is added as a low-concentration ethanolic solution to the particles, while these still form a flexible gel. Cross-linking of the particles in an autoclave, followed by drying and calcination, leads to bimodal materials with the controlled small mesopores of MCM-41, and a larger meso- to macropore size distribution that depends on the micelle shape and size. The latter is a function of the conditions in the second step, such as the amount and composition of the surfactant, the aging time, the temperature, the pH and the type of solvent. Fine tuning of this procedure, application to other primary structured particles, and combination with other structuring methods, should enable to construct multi-structured hierarchical materials with a desired texture at all scales.     

依靠技术进步,推进“十二五”期间氮肥和甲醇行业的科学发展——在2011年技术经验交流会上的讲话

"十一五"期间,我国氮肥和甲醇行业的原料结构调整取得了重大进展,特别是大型国产化的对置式多喷嘴、多元料浆、熔渣-非熔渣及水冷壁式水煤浆气化技术和航天炉连续气化技术的开发成功,大大推进了我国氮肥和甲醇工业的现代化进程。"十二五"期间,应充分发挥技术进步作用,优胜劣汰,提高行业整体水平;总结并进一步推广"十一五"节能降耗成果;加强节能技术和大型化装置的开发研究,使我国氮肥工业达到国际先进水平;调整产品结构,肥化并举,建立多层次、多产品的化工生产体系,延伸产品链,提高附加值,提升企业经济效益和竞争力;狠抓污染物减排,提高行业环保水平;加强技术管理,建立现代化企业。"十二五"时期,氮肥及甲醇企业要按照科学发展观的要求,依靠技术进步,加大结构调整的力度,实现氮肥和甲醇工业的科学发展,为我国农业和国民经济发展做出更大贡献。     

Fabrication and characterization of hierarchical porous Ni2+ doped hydroxyapatite microspheres and their enhanced protein adsorption capacity

Hydroxyapatite (HAP) is a common bio-adsorbent, which performance depends heavily upon its morphology and microporous structure. In this study, a novel synthesis strategy was proposed for hierarchical porous HAP microspheres by a simple “one-pot” hydrothermal reaction. In the strategy, L-glutamic acid serves as soft template to modulate the morphology and inner crystalline of HAP. To evaluate the application potential, doping Ni²⁺ on hierarchical porous HAP microspheres gives metal chelated affinity adsorbents. The prepared adsorbents show a perfect spherical shape, particles size of 96.6 μm, relatively specific surface area of 48.5 m²·g^-1 and hierarchical pores (mesopores: 4 nm and macropores: 53 nm). By the adsorption evaluation, it reveals that the Ni²⁺-HAP adsorbents have high adsorption capacities of 275.11 and 97.55 m²·g^-1 for hemoglobin and bovine serum albumin, respectively, which is comparable to other similar adsorbent. Therefore, this work provides a promising method for high-efficiency hydroxyapatite microspheres for proteins purification.     

Film instability induced evolution of hierarchical structures in annealed ultrathin films of an asymmetric block copolymer on polar substrates

With an atomic-force microscope and a grazing-incidence small-angle X-ray scattering we studied ex situ the evolution of hierarchical structures in isothermally annealed ultrathin films of asymmetric polystyrene-block-poly(methyl methacrylate) P(S-b-MMA) that dewetted on polar substrates via a mechanism involving nucleation and growth. Film instability causes the surface to acquire an undulating thickness through incommensurability, producing not only the relief structures on a micrometer scale but also mesophase-separated domains on a nanometer scale. The dewetted morphologies strongly influence the ordering behavior of the nanoscale domains. The noncylindrical nanostructures become stable at the curved edges of the relief microstructures in the destabilized P(S-b-MMA) films, for which a preferential wetting of the PS block with the free surface is prohibited. Additionally, the shape of relief structures as result of film instability correlates with the formation of mesophase-separated nanodomains. At early stages of film instability, the formation of parallel-oriented PMMA cylindrical nanodomains increases the deformation energy and it further persists to force the shape of relief structures between irregular holes to have a facet-wedge shape. However, those relief structures are expected to be not at equilibrium. At high temperatures, the relief structures between irregular holes progressively developed to form hemispherical-cap drops accompanied by a transformation of cylindrical into noncylindrical nanodomains at curved surfaces.     

Hierarchically structured Bi2MoxW1-xO6 solid solutions with enhanced piezocatalytic activities

Hierarchical structure Bi₂Mo_xW_1-xO₆ (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) solid solutions with high surface area are prepared by hydrothermal method without employing any surfactant. All the as-prepared products are hierarchical microspheres self-assembled by nanosheets. The piezocatalytic performance of Bi₂Mo_xW_1-xO₆ solid solutions are investigated by the degradation of RhB under ultrasonic vibration. The experimental results show that the x value of Bi₂Mo_xW_1-xO₆ has great influence on the piezocatalytic efficiency. Among which, the Bi₂Mo_0.4W_0.6O₆ presents a high value of the rate constant k of 0.119 min^-1 by degrading 97.5% of RhB dye solution in 30 min. It is about 43.4% higher than that of pure Bi₂WO₆ sample, for which k is 0.083 min^-1. Radical trapping test indicates that holes (h⁺) are the dominating active species in the degradation process. The improved piezocatalytic performance for Bi₂Mo_0.4W_0.6O₆ sample ascribes to the larger piezoelectric potential generated under a strained state, which facilitates the transfer of charge carriers and accelerate the piezocatalytic process. Our work presents a new design strategy of piezocatalysts for remediation of water pollution.