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。

具有微/纳多孔结构的海胆状NiO的制备及其比容量研究

以六水合氯化镍和尿素为原料,利用水热合成法制备了具有微/纳多孔结构的海胆状NiO的前驱物,经热处理后得到了具有微/纳多孔结构的海胆状NiO微球。通过XRD、SEM、HRTEM和N2-吸附-脱附对制得的NiO微球进行了表征,结果显示表面具有5～20nm微孔的海胆状NiO微球由许多直径30～40nm的纳米线组装而成,其比表面积高达325.238m2/g,孔体积0.338cm3/g。充放电测试结果表明,在0.5～3V电压范围、0.1C倍率下,具有微/纳多孔结构海胆状NiO材料的首次放电比容量高达1636.2mAh/g,对比实验显示,其放电比容量远远高于合成的NiO纳米颗粒的首次放电比容量(792.8mAh/g),且高于已有文献报道的其它形貌NiO材料的放电比容量。

微多孔聚酯短纤维织物的制备与性能

为了研究微多孔聚酯短纤维织物的湿传递性能,以165 dtex/48 f低弹涤纶网络丝为经纱、14.76 tex×2微多孔聚酯短纤维氨纶包缠纱为纬纱,根据不同的织物组织结构和有无亲水处理,开发了4种平纹和斜纹织物。比较不同组织结构和有无亲水处理织物的吸湿性能。结果表明:较为稀松的斜纹织物吸湿性要比紧密的平纹织物好;经亲水处理的织物吸湿性能与未经亲水处理的织物相差不大;微多孔聚酯纤维因自身具有较好的液态水传递能力,而无需亲水处理;用初始芯吸速率可表征织物液态水传递能力。

Fabrication of porous g-C_3N_4 and supported porous g-C_3N_4 by a simple precursor pretreatment strategy and their efficient visible-light photocatalytic activity

Porous g-C_3N_4 and supported porous g-C_3N_4 were fabricated for the first time by a simple strategy using pretreated melamine as a raw material and pretreated quartz rod as a substrate.The formation of a richly porous microstructure can be attributed to the co-existence of different pore-fabricating units in the preparation system for porous g-C_3N_4.The richly porous microstructure endowed the as-prepared porous g-C_3N_4 with an excellent photocatalytic activity.The as-prepared supported porous g-C_3N_4 exhibited considerable stability because of the existence of chemical interaction between porous g-C_3N_4 and the quartz rod substrate.The photocatalytic activity of the supported porous g-C_3N_4 was competitive with that of porous g-C_3N_4 in powder form because neither the surface migration of photogenerated electrons nor the diffusion of the target organic pollutant were affected by the construction of the quartz rod reactor.The photocatalytic activity of the as-prepared porous g-C_3N_4 and supported porous g-C_3N_4 was preliminarily evaluated by the treatment of single-component organic wastewater under visible-light irradiation.Subsequently,the as-prepared porous g-C_3N_4 was further applied in conventional hydrogen evolution and a new system for simultaneous hydrogen evolution with organic-pollutant degradation.The hydrogen yield and degradation efficiency both increased with increasing photocatalytic activity of the as-prepared materials in the system for simultaneous hydrogen evolution with organic-pollutant degradation.

Solid-phase sintering process and forced convective heat transfer performance of porous-structured micro-channels

A solid-phase sintering process for the low-cost fabrication of composite micro-channels was developed. Three kinds of composite micro-channels with metallic porous structures were designed. The sintering process was studied and optimized to obtain porous-structured micro-channels with high porosity. The flow resistance and heat transfer performance in the composite micro-channels were investigated. The composite micro-channels show acceptable flow resistance, significant enhancement of heat transfer and dramatic improvement of flow boiling stability, which indicates a promising prospect for the application in forced convective heat transfer.

Low temperature molten salt synthesis of porous La_(1-x)Sr_xMn_(0.8)Fe_(0.2)O_3(0≤x≤0.6) microspheres with high catalytic activity for CO oxidation

A molten salt method was developed to prepare porous La1‐xSrxMn0.8Fe0.2O3 （0≤ x ≤ 0.6） micro‐spheres using hierarchical porous δ‐MnO2 microspheres as a template in eutectic NaNO3‐KNO3. X‐ray diffraction patterns showed that single phase LaMn0.8Fe0.2O3 with good crystallinity was syn‐thesized at 450℃ after 4 h. Transmission electron microscope images exhibited that the LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h possessed a porous spherical morphology com‐posed of aggregated nanocrystallites. Field emission scanning electron microscope images indicated that the growth of the porous LaMn0.8Fe0.2O3 microspheres has two stages. SEM pictures showed that a higher calcination temperature than 450？？ had an adverse effect on the formation of a po‐rous spherical structure. The LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h displayed a high BET surface area of 55.73 m2/g with a pore size of 9.38 nm. Fourier transform infrared spectra suggested that Sr2＋ions entered the A sites and induced a decrease of the binding energy between Mn and O. The CO conversion with the La1‐xSrxMn0.8Fe0.2O3 （0≤x≤0.6） samples indicated that the La0.4Sr0.6Mn0.8Fe0.2O3 sample had the best catalytic activity and stability. Further analysis by X‐ray photoelectron spectroscopy demonstrated that Sr2＋doping altered the content of Mn4＋ions, oxygen vacancies and adsorbed oxygen species on the surface, which affected the catalytic performance for CO oxidation.

Synthesis of porous nano/micro structured LiFePO_4/C cathode materials for lithium-ion batteries by spray-drying method

In order to enhance electrochemical properties of LiFePO4 （LFP） cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The results show that the spherical precursors with the sizes of 0.5-5 μm can be completely converted to LFP/C when the calcination temperature is higher than 500 ℃. The LFP/C microspheres obtained at calcination temperature of 700 ℃ are composed of numerous particles with sizes of -20 nm, and have well-developed interconnected pore structure and large specific surface area of 28.77 mE/g. The specific discharge capacities of the LFP/C obtained at 700 ℃ are 162.43, 154.35 and 144.03 mA.h/g at 0.5C, 1C and 2C, respectively. Meanwhile, the capacity retentions can reach up to 100% after 50 cycles. The improved electrochemical properties of the materials are ascribed to a small Li＋ diffusion resistance and special structure of LFP/C microspheres.

Hierarchical porous Co_(3)O_(4) spheres fabricated by modified solvothermal method as anode material in Li-ion batteries

Hierarchical porous Co_(3)O_(4)spheres were synthesized by a solvothermal method followed by high-temperature calcination.XRD,SEM,TEM and electrochemical tests were used to study the structure and performance of the hierarchical porous Co_(3)O_(4)spheres.The results show that the Co_(3)O_(4)synthesized at a calcination temperature of 700°C(Co_(3)O_(4)-700)is micro-sized spheres(1-2μm)consisting of plentiful nanoparticles(50-200 nm)and numerous pores(~100 nm).Due to its numerous porous morphology,the Co_(3)O_(4)-700 anode exhibits the highest cycling performance with excellent reversible discharge and charge specific capacities of 745 and 755 m A·h/g at the current density of 100 m A/g after 100 charge-discharge cycles,respectively.

High conductive graphene assembled films with porous micro-structure for freestanding and ultra-low power strain sensors

Graphene emerges as an ideal material for constructing high-performance strain sensors,due to its superior mechanical property and high conductivity.However,in the process of assembling graphene into macroscopic materials,its conductivity decreases significantly.Also,tedious fabrication process hinders the application of graphene-based strain sensors.In this work,we report a freestanding graphene assembled film(GAF)with high conductivity((2.32±0.08)×105 S m-1).For the sensitive materials of strain sensors,it is higher than most of reported carbon nanotube and graphene materials.These advantages enable the GAF to be an ultra-low power consumption strain sensor for detecting airflow and vocal vibrations.The resistance of the GAF remains unchanged with increasing temperature(20-100℃),exhibiting a good thermal stability.Also,the GAF can be used as a strain sensor directly without any flexible substrates,which greatly simplifies the fabrication process in comparison with most reported strain sensors.Additionally,the GAF used as a pressure sensor with only^4.7μW power is investigated.This work provides a new direction for the preparation of advanced sensors with ultra-low power consumption,and the development of flexible and energy-saving electronic devices.

Effect of agarose content on microstructures and mechanical properties of porous silicon nitride ceramics produced by gelcasting

Porous Si3N4 self-reinforce ceramics were prepared by gelcasting using agarose solutions. By changing the agarose content in the slurries, the porous silicon nitride ceramics with different porosities, α→β-Si3N4 phase transformation, and mechanical properties were obtained. When the agarose content changed from 0.2% to 0.8% (w/w, based on powder), the porosities increased from 10.3% to 21.4%, while the fracture strength decreased from 455 to 316 MPa and the fracture toughness decreased from 6.6 to 5.5 MPa·m1/2. Many fibrous β-Si3N4 grains grown from the internal wall of the round pores is the typical microstructure of the gelcasting porous silicon nitride ceramic. Both elongated β-Si3N4 grains and suitable interfacial bonding strength contributes to high fracture toughness by favoring crack deflection and bridging. The growth mechanisms of fibrous grains resulted from the synergy of solution-diffusion-reprecipitation and vapor-liquid-solid (VLS).

Manufacture of porous metallic glass using dissolvable templates

A facile,precise,and controllable manufacturing technology is desired for hierarchical functional surfaces.In this work,we successfully manufactured porous metallic glass using a water-dissolution material as template and the excellent thermoplastic property of metallic glass.The prepared micro/nanostructures have excellent tunability,and the proposed approach can be used to prepare large-area disordered porous structures and ordered regular arrays with nanoscale replication accuracy.In particular,the disordered porous structure prepared by the dissolvable template strategy exhibits a water contact angle of~140°and an oil contact angle of~0°,making it suitable for oil/water separation.It also shows stable wettability after being soaked in strong acid or alkali environments and maintains a~130°water contact angle and a~4°oil contact angle even after severe wear.The proposed strategy also possesses excellent recycling properties.We reconstructed porous structures on the same surface three times and found no significant change in wettability for each reconstructed porous structure.Our research provides a facile and controllable approach for the preparation of hierarchical porous structures and paves the way for the design of other functional surfaces.

Transparent and flame retardant cellulose/aluminum hydroxide nanocomposite aerogels

Cellulose-based nanocomposite aerogels were prepared by incorporation of aluminum hydroxide(AH) nanoparticles into cellulose gels via in-situ sol-gel synthesis and following supercritical CO_2 drying. The structure and properties of cellulose/AH nanocomposite aerogels were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy,ultraviolet-visible spectrometry, N_2 adsorption, thermogravimetric analysis, and micro-scale combustion calorimetry. The results indicated that the AH nanoparticles were homogeneously distributed within matrix, and the presence of AH nanoparticles did not affect the homogeneous nanoporous structure and morphology of regenerated cellulose aerogels prepared from1-allyl-3-methylimidazolium chloride solution. The resultant nanocomposite aerogels exhibited good transparency and excellent mechanical properties. Moreover, the incorporation of AH was found to significantly decrease the flammability of cellulose aerogels. Therefore, this work provides a facile method to prepare transparent and flame retardant cellulose-based nanocomposite aerogels, which may have great potential in the application of building materials.