A Combination of N2 and CO2 Adsorption to Characterize Nanopore Structure of Organic-Rich Lower Silurian Shale in the Upper Yangtze Platform, South China： Implications for Shale Gas Sorption Capacity

The pores in shales are mainly of nanometer-scale, and their pore size distribution is very important for the preservation and exploitation of shale gas. This study focused on the organic-rich Lower Silurian black shale from four wells in the Upper Yangtze Platform, and their TOC, mineralogical composition and pore characterization were investigated. Low pressure N2 and CO2 adsorption were conducted at 77.35 K and 273.15 K, respectively, and the pore structures were characterized by modified Brunauer-Emmett-Teller （BET）, Dubinin-Radushkevich （DR）, t-plot, Barrett- Joyner-Halenda （BJH） and density functional theory （DFT） methods and then the relationship between pore structure and shale gas sorption capacity was discussed. The results indicate that （1） The Lower Silurian shale has high TOC content of 0.92%~96%, high quartz content of 30.6%-69.5%, and high clays content of 24.1%-51.2%. The total specific surface area varies from 7.56 m^2/g to 25.86 m^2/g. Both the total specific surface area and quartz content are positively associated with the TOC content. （2） Shale samples with higher TOC content have more micropores, which results in more complex nanopore structure. Micropore volumes/surface areas and non-micropore surface areas all increase with the increasing TOC content. （3） A combination of N2 and CO2 adsorption provides the most suitable detection range （~0.3-60 nm） and has high reliability and accuracy for nanopore structure characterization. （4） The TOC content is the key factor to control the gas sorption capacity of the Lower Silurian shale in the Upper Yangtze Platform.

Evolution of porous structure with dealloying corrosion on Gasar Cu-Mn alloy

The evolution of nanoporous structure with dealloying condition was investigated, thus, the mechanism of porous structure evolution was uncovered. The Gasar Cu-Mn alloy was dealloyed by room and elevated temperature chemical corrosion, low and high current level electrochemical corrosion, four types of porous structures, including uneven corrosion pits, hybrid porous, haystack type and bicontinuous model were prepared by chemically and electrochemically dealloying the porous Cu-34.6%Mn alloy made by the Gasar process. Then, the surface diffusion coefficient(DS) and the diffusion frequency(kD) of Cu atom, as well as the dissolution frequency(kE) of Mn atom were calculated with dealloying condition. The dealloyed morphologies for room temperature chemical corrosion and low current level electrochemical corrosion were similar due to the same DS. While the dealloyed structures changed from bulk hybrid porous structure to bicontinuous porous film with decreasing kD/kE.

Fabrication of high-strength duplex nanoporous Cu by dealloying a dual-phase Mg-Cu precursor alloy

Duplex nanoporous Cu was successfully fabricated by dealloying a dual-phase Mg-Cu precursor alloy consisting of intermetallic Mg2Cu and MgCu2.The duplex nanoporous Cu with embedded nanoporous struts exhibited highly enhanced strength compared to the typical monolithic nanoporous Cu under both compressive and flexural test conditions at room temperature;the duplex np-Cu sample exhibited a 12 times higher compressive strength and a 40 times greater flexural strength than the monolithic np-Cu sample.Factors responsible for the strength enhancement in the duplex nanoporous Cu are discussed.

Degradation efficiency of Mg_(65)Cu_(25-x)Ag_(x)Y_(10) nanoporous dealloyed ribbons on pesticide wastewater

Dealloyed ribbons with a layer of networked nanoporous structure of different pore sizes were fabricated by dealloying the as-spun Mg_(65)Cu_(25-x)Ag_(x)Y_(10)(x=0,5,10,at.%)ribbons in dilute H_(2)SO_(4) solution in order to enhance the degradation efficiency of pesticide wastewater.Compared to the as-spun ribbons,it is found that the dealloyed ribbons with the networked nanoporous structure exhibit higher degradation efficiency due to their large specific surface areas and enough active sites for the degradation process.Both the average pore sizes of the nanoporous structure and the degradation efficiency of the pesticide wastewater increase with the increase of Ag addition in the dealloyed ribbons.The maximum degradation efficiency up to 95.8%is obtained for the Mg_(65)Cu_(15)Ag_(10)Y_(10)dealloyed ribbon under the optimal conditions of pH being 3,the initial cis-cypermethrin concentration being 500 mg/L,and the dosage of dealloyed ribbon being 1.33 g/L.

Self-Supported Nanoporous Gold with Gradient Tin Oxide for Sustainable and Efficient Hydrogen Evolution in Neutral Media

Hydrogen evolution reaction(HER)in neutral medium suffers from slow kinetics as compared to that in alkaline or acidic conditions,owing to larger Ohmic loss and low proton concentration.Here we report that a self-supported nanoporous Au-SnO_(x)(NP Au-SnO_(x))catalyst with gradient tin oxide surface could significantly enhance HER activity in neutral buffer solution(0.2 M PBS).The NP Au-SnO_(x)catalyst exhibits a low onset overpotential of 38 mV and a small Tafel slope of 79 mV dec^(−1).The current density of 10 mA cm^(−2)is manifested at an overpotential as low as 148 mV,representing the comparable performance of Pt/C catalyst.This high catalytic activity can retain at least 10 hours without any detectable decay.The superior HER activity is proposed to originate from the gradient SnO_(x)structure and metal/oxide interfaces in nanoporous ligaments.Furthermore,the X-ray photoelectron spectroscopy reveals that the gradient oxide in the ligament is remarkably stable during long-term reaction.

Liquid metal assisted regulation of macro-/micro-structures and mechanical properties of nanoporous copper

Nanoporous metals have received significant attention as a new class of structural and functional materials.However,the macroscopic brittle fracture under the tensile test is an impediment to their practical applications.Thus,it is of central importance to develop nanoporous materials with low cost and high tensile ductility.Herein,a nanoporous Cu film supported on a pure Cu substrate(NPC@Cu)was fabricated by utilizing a liquid Ga assisted alloying-dealloying strategy,and the thickness of NPC film can be precisely regulated by changing the mass loading of liquid Ga.In-situ X-ray diffraction was performed to further explore the alloying/dealloying mechanisms.The NPC@Cu films show good tensile mechanical properties with a minimum elongation of 13.5%,which can be attributed to the good interface bonding and certain modulus matching between the nanoporous Cu layer and the Cu substrate.Our findings demonstrate that the design of film-substrate structure provides a feasible strategy for enhancing the mechanical properties of nanoporous metals.

Study on Acoustic Performance for Diatom Frustule with Nanoporous Structure

The acoustic performance for the nanoporous frustule of the diatom is studied based on the computational fluid dynamics theory and acoustic theory involved.Representative Coscinodiscus sp.frustule is observed through the scanning electron microscope and modeled by the commercial software Solidworks.Further,the acoustic performance for the Coscinodiscus sp.frustule is studied at the varied depth,diameter or interval of the pore,as well as the film thickness of the fluid surrounding the Coscinodiscus sp.frustule.The numerical results show that,when the upper and lower pore diameters are separately 200 and 300 nm,the upper and lower pore depths are separately 200 and 250 nm,and both the pore interval and fluid film thickness are 500 nm,the elaborate nanoporous structure of Coscinodiscus sp.frustule can lower its acoustic power level by 17.49%,compared with that without porous structure.Meanwhile,the double-layer pore of Coscinodiscus sp.frustule can decrease its acoustic power level by 12.69%,compared with its single-layer pore structures.

Self-supporting nanoporous Ni/metallic glass composites with hierarchically porous structure for efficient hydrogen evolution reaction

Searching for free-standing and cost-efficient hydrogen evolution reaction(HER)electrocatalysts with high efficiency and excellent durability remains a great challenge for the hydrogen-based energy industry.Here,we report fabrication of a unique hierarchically porous structure,i.e.,nanoporous Ni(NPN)/metallic glass(MG)composite,through surface dealloying of the specially designed Ni_(40)Zr_(40)Ti_(20)MG wire.This porous composite is composed of micrometer slits staggered with nanometer pores,which not only enlarges effective surface areas for the catalytic reaction,but also facilitates the release of H2 gas.As a result,the NPN/MG hybrid electrode exhibited the prominent HER performance with a low overpotential of 78 m V at 10 m A cm^(-2)and Tafel slope of 42.4 m V dec^(-1),along with outstanding stability in alkaline solutions.Outstanding catalytic properties,combining with their free-standing capability and cost efficiency,make the current composite electrode viable for HER applications.

三维柱阵列型纳米多孔硫化亚锡负极的电化学合成与储锂性能研究

本研究在铜箔基底上通过无模板恒流电沉积技术成功制备出三维柱阵列型纳米多孔铜镍集流体。采用恒压电沉积方式在该集流体表层沉积SnS纳米颗粒,形成了具有三维柱状结构的纳米多孔硫化亚锡电极。利用恒流充放电测试与XRD、SEM、EDS技术,综合评估了该负极的电化学特性、微观结构、化学元素分布及其物相成分。结果表明,所制备的纳米柱表面存在孔隙,阵列间隙均匀。在0.1 mA/cm^(2)电流密度下,该电极首次放/充电过程中分别提供了0.77/0.48 mAh/cm^(2)的面积比容量,首次库仑效率为62%。经过50周循环后,电极可逆比容量仍达0.30 mAh/cm^(2),容量保持率为62.5%。

发酵乳杆菌GZHN2023LC的益生特性及其全基因组测序分析

为探究威宁黄牛源发酵乳杆菌的潜在益生特性和开发益生菌制剂的可行性,本研究进行了益生菌的分离鉴定、耐酸耐胆盐试验、抑菌试验和全基因组测序研究。结果:从35份样品中分离得到11株发酵乳杆菌,均对低pH值和胆盐有良好的抗性,尤其是发酵乳杆菌5;抑菌试验发现发酵乳杆菌5有显著的抑制大肠杆菌的效果,将其命名为GZHN2023LC。基因组测序发现该菌基因组全长达2077921 bp,共编码2011个蛋白;经京都基因与基因组百科全书(KEGG)、直系同源簇(COG)、基因本体论(GO)、碳水化合物活性酶(CAZy)等数据库比对,发现该基因组碳水化合物和氨基酸代谢能力强,同时转录和膜运输活跃,可能与其发酵多糖产生乳酸以及能够合成抗菌肽、胞外多糖有关。综上,发酵乳杆菌GZHN2023LC能够快速增殖,对酸和耐盐有良好的抗性,且有显著的抗菌特性,基因组测序也发现该菌有良好的益生潜能,具备用于益生菌制剂的潜力。

Characterization of the nanopore structures of PAN-based carbon fiber precursors by small angle X-ray scattering

The nanopore structures in precursors Four carbon-fiber precursors are prepared. They are crucial to the performance of PAN-based carbon fibers are bath-fed filaments （A）, water-washing filaments （B） hot-stretching filaments （C） and drying-densification filaments （D）. Synchrotron radiation small angle X-ray scattering is used to probe and compare the nanopore structures of the four fibers. The nanopore size, discrete volume distribution, nanopore orientation degree along the fiber axis and the porosity are obtained. The results demonstrate that the nanopores are mainly formed in the water-washing stage. During the processes of the subsequent production technologies, the slenderness ratio of nanopores and their orientation degree along the fiber axis increase further and simultaneously, the porosity decreases. These results are helpful for improving the performance of the final carbon fibers.

页岩气储层孔隙系统表征方法研究进展

页岩气是以游离、吸附和溶解状态赋存于暗色泥页岩中的天然气,页岩的孔隙特征是决定页岩储层含气性的关键因素。页岩孔隙结构复杂,一般以纳米孔隙占优势,用常规储层孔隙的表征方法难以解释美国的高产页岩气系统。因此,页岩纳米孔隙的表征成为制约页岩气资源评价的关键因素。在综述目前国际上对页岩气储层孔隙表征方法的基础上,对比分析其各自的适用范围和应用前景。页岩储层孔隙的主要表征方法有3种:(1)以微区分析为主的图像分析技术;(2)以压汞法和气体等温吸附为主的流体注入技术;(3)以核磁共振、中子小角散射计算机断层成像技术为代表的非流体注入技术。图像分析能够直观、方便、快捷地获取孔隙形态等方面的特征;流体注入法在表征微孔隙的孔径分布、比表面积等方面具有独到优势;非流体注入技术由于其原位、无损分析及粒子高穿透力的特点,使研究多种地质条件下的孔隙特性成为可能。在目前的技术条件下,应明确各种表征技术的优势与限制,根据实际情况合理建立孔隙研究流程,综合利用多种技术手段能在不同的尺度下有效表征页岩气储层孔隙。

川南龙马溪组页岩气储层纳米孔隙结构特征及其成藏意义

以川南龙马溪组页岩气储层为例,运用氮气吸附法对储层纳米孔隙进行测定,通过等温线和DFT分析,对孔结构特征表征并讨论控制纳米孔隙结构的主因和纳米孔隙对页岩气成藏的意义。结果表明:龙马溪组页岩气储层孔隙结构较复杂,主要由纳米孔组成,具有一定的无规则孔结构,孔隙多呈开放形态,以两端开口的圆筒孔及4边开放的平行板孔等开放性孔为主;垂向上由深到浅,孔隙开放程度减小;纳米主孔位于2～40 nm,占孔隙总体积的88.39%,占比表面积的98.85%;2～50 nm的中孔提供了主要的孔隙体积,小于50 nm的微孔和中孔提供了主要的孔比表面积;TOC是控制该储层中纳米孔隙体积及其比表面积的主要内在因素,也是提供页岩气主要储存空间的重要物质;纳米孔对页岩气的吸附能力极强,在其内部有大量页岩气以结构化方式存在,增加了页岩气的存储量,并使模型表征复杂化;开放状纳米孔可提高页岩气解吸效率和储层渗透率,提高页岩气的产量。

纳米多孔结构镍基复合膜电极的电化学法制备及其电容特性

通过对电沉积法得到的Ni-Cu合金镀层进行电化学去合金化处理,制备了纳米多孔结构金属镍膜.采用循环伏安法对多孔金属镍膜在1mo·lL-1KOH溶液中进行阳极氧化处理,获得了纳米多孔结构的镍基复合膜电极.应用扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和电化学技术对所制备的膜电极的物理性质及赝电容特性进行了表征.SEM、XRD和XPS的测试结果表明,所制备的纳米多孔结构镍基复合57膜8F由·gN-i1、的N初i(O始H比)2和电N容iO;在OH1组00成0次.电充化放学电实循验环结后果,它显的示比,该电复容合值膜为在54240F·A·gg-1-,1的电充容保放持电率电为流密94度%下.纳,给米出多孔了结构有利于KOH电解液的渗透,从而促进反应物种在电极内部的传输;纳米多孔的金属镍基体可以提高Ni(OH)2膜的电子导电性;纳米大小的Ni(OH)2颗粒能够缩短质子的固相扩散路径.上述因素是所制备的纳米多孔结构镍基复合膜电极具有优异赝电容特性的主要原因.

页岩储层孔隙特征与结构的观察研究

页岩气储层孔隙特征与微观结构对页岩气勘探开发具有重要意义。以五峰组、龙马溪组样品为例,使用常规扫描电镜、氩离子抛光-场发射扫描电镜对孔隙特征、微观结构进行观测,识别出多种成因-形貌孔隙类型,对储层孔隙特征进行了刻画,认为页岩储层孔隙主体处于纳米级别,孔隙形态复杂,类型多样,微裂隙发育;微米级的孔隙与微观结构可以由常规扫描电镜直接观测,而氩离子抛光蚀刻处理有利于纳米级孔隙的定性观测。分析对比了常规扫描电镜、氩离子抛光-场发射扫描电镜试验方法的优势与不足,提出将定性与定量研究手段相综合,在利用扫描电镜系统观测页岩储层孔隙结构的基础上,结合使用高压压汞、气体吸附等定量化方法可以全面描述页岩孔隙特征,是目前对页岩储层孔隙特征进行综合表征的最佳手段。

氩离子抛光-场发射扫描电镜在煤纳米孔研究中的应用

随着煤层气勘探开发与二氧化碳地下储存技术的发展,煤储层微观孔隙结构的研究逐渐向纳米级别深入。以太原组无烟煤为例,率先采用氩离子抛光-场发射扫描电镜技术直接观测煤纳米孔,为煤储层微观储渗结构的观测提出一种新的研究方法。结果表明,煤储层孔隙主体处于纳米级别,分别发育在炭质、颗粒矿物、粘土矿物内部及接触部位,类型多样,以炭质内部的纳米孔最为发育;孔径差异显著,孔径主体分布范围为10～700 nm,集中在50～100 nm;孔隙形貌特征复杂、连通性不均一。氩离子抛光-场发射扫描电镜在煤微观孔隙系统分类及微观结构辅助定性-定量表征两方面具有广阔运用前景。

纳米孔玻态炭的成孔机理与“壳芯”结构

研制的纳米孔玻态炭电极,整体呈纳米开孔结构,电容特性优良,全面超过了中孔碳气凝胶．其成孔机理研究表明:通过添加适量的固化剂-六次甲基四胺,经球磨固混后,调节固化温度,造成固化树脂颗粒内芯与外壳的交联度不同,形成“壳芯”结构;粉碎压制时, 内芯作为外壳的粘合剂使材料成型,炭化时壳层不融化而阻挡内芯熔并成玻态炭．于是,碳粒内外形成丰富的开放孔隙,活化剂气体能够扩散渗入体相进行活化而得纳米孔玻态炭．

430不锈钢表面微纳多孔结构阳极氧化膜的制备及疏水性研究

利用扫描电镜（SEM）研究了阳极氧化工艺对 SUS430不锈钢在由氟化铵、水及乙二醇（Eg）组成的电解液中制备微纳多孔结构氧化膜的影响，通过能谱仪（EDS）对阳极氧化膜微孔内部和未成孔位置的组成进行了分析，测试了阳极氧化前后不锈钢表面的水接触角。适当降低电解液含水量有利于提高不锈钢表面的微孔密度，可形成微纳多孔结构的氟化铵浓度以0.15 mol/L最好，氧化电压过大以及氧化时间过长都会导致阳极氧化膜发生过度腐蚀。在氟化铵含量为0.15 mol/L、含水量小于0.4 mol/L的电解液中，保持电解液温度为20°C，采用氧化电压50~60 V阳极氧化15~30 min，不锈钢表面可制备出孔径为3~5μm的多孔结构，微米级孔洞内部形成有序的蜂窝状纳米多孔结构（孔径约为100 nm）。阳极氧化后不锈钢表面形成了氧化物和氟化物，与水的接触角为138.2°，具有较好的疏水性。

组合结构对多层反射纳米材料高温隔热性能的影响

以超薄纳米隔热材料为间隔物、金属箔为反射层制备了多层反射纳米隔热材料,通过改变隔热材料的组合结构测试其隔热效果。结果表明:在研究范围内增加不锈钢箔层数、将不锈钢箔放置在低温区或在低温区用铝箔替代不锈钢箔都对隔热效果有利;测试温度高时隔热效果更好。