Synthesis of ZnS nanoparticles into the pore of mesoporous silica spheres

The ZnS nanoparticles were exclusively synthesized in the pores of the mesoporous silica (MS) particles which had been coated with two bilayers of poly(allylamine hydrochloride) (PAH)/poly(styrene sulfonate) (PSS) via the layer-by-layer (LbL) self-assembly technique. Measurements and analysis of XRD and TEM showed that the ZnS nanocrystals were inserted into the pores of the MS spheres. This approach can be used to prepare composite materials involving functional inorganic nanoparticles which have potential application in biological immunoassay and photoelectronic fields.     

结构有序、双重孔隙中孔炭材料的合成与表征

采用纳米涂层技术,以介孔分子筛SBA 15为模板,在其纳米孔道内引入糠醇/草酸溶液,经原位聚合,炭化后制得炭/SBA 15复合物。采用化学法脱除模板后制得具有规则结构的中孔炭。高分辨TEM表征结果显示该中孔炭是由纳米炭管相互联接、堆积而成,且具有六方对称结构。氮吸附结果显示其比表面积高达2000m2/g,孔径呈双峰分布。孔径相对较大的孔隙来源于SBA 15孔道经纳米涂层后所保留的孔隙;孔径相对较小的孔隙来源于SiO2移除后遗留的纳米孔空间。该方法可应用于以其他多孔氧化硅为模板制备新型纳米复合物的研究过程。     

High rate capability of ordered mesoporous carbon with platelet graphitic pore walls for lithium ion anodes

An ordered mesoporous carbon (OMC) with controllable molecule crystal and platelet graphitic pore walls, which is directionally grown on the internal pore walls of SBA-15 or anchors at liquid/silica interfaces by molecule engineering, has been investigated as lithium ion anodes. It is found that the OMC exhibits high kinetics, rate and cycling performance. The i₀ and D_Li are almost constant after 50 cycles. OMC shows a high reversible specific capacity of 153.9 mAh g^-1 at the current density as high as 3500 mA g^-1. The excellent electrochemical performance could be attributed to the presence of the porosity and platelet graphitic pore walls.     

Morphologically controlled synthesis of mesoporous alumina using sodium lauroyl glutamate surfactant

Mesoporous alumina with various morphologies has been successfully synthesized by a proper sol-gel process using sodium lauroyl glutamate surfactant as a template. Both the mesostructures and morphologies of the resulting alumina can be effectively controlled by adjusting the concentration of the sodium lauroyl glutamate surfactant present in the reaction system. Through characterization by X-ray diffraction, transmission electron microscopy, and N₂ physisorption, the effects of sodium lauroyl glutamate on the mesostructure and morphology of the resulting materials have been investigated in detail, and a possible formation mechanism of the controlled morphologies is proposed. The resulting mesoporous materials showed a potential application in adsorption of toxic organic compounds, which was attributed to the porous structure, high BET surface area, and large pore volume.     

Using phenol–formaldehyde resin as carbon source to synthesize mesoporous carbons of different pore structures

In this research communication, we performed the phenol–formaldehyde (PF) resin as an alternative carbon source and various mesostructured silicas as the nano-templates to conveniently prepare the mesoporous carbons of high surface area (850–1500 m² g⁻¹), large pore size (2.0–22.0 nm) and great pore volume (0.65–1.15 cm³ g⁻¹). It was reasonably supposed that there exist interaction matching between the negative-charged silica surface of the silica template and PF resin. Therefore, the PF oligomers could be homogeneously adsorbed into the nanochannels or cages of the mesoporous silicas via an impregnation process. Because the thermosetting PF resin only requires a simple heat treatment process at 100 °C to form the cross-linked polymeric structure, the replication of the mesostructure of the mesoporous silica template could be readily achieved without adding any polymerization catalysts.     

Highly mesoporous carbon with high capacitance from carbonization of phenol-formaldehyde resin

Porous carbon material with high surface area and highly mesoporous structure has been successfully prepared from phenol-formaldehyde resin by combining Polyethylene Glycol (PEG) and ZnCl₂ as activation agents. The as-prepared carbon material exhibits large specific double layer capacitance of 122 F g^− 1 at 120 mA g^− 1 in the electrolyte of 1 M Et₄NBF₄/PC, which is attributed to its high specific surface area and well-developed mesopores. Moreover, it can retain as high as 86.88% of its initial specific capacitance, when the specific current increases from 120 mA g^− 1 to 2 A g^− 1. It is also found that the energy density of this material still maintains up to 21.2 Wh kg^− 1 at the power density of 2400 W kg^− 1.     

A novel kind of porous carbon nitride using H-magadiite as the template

A novel kind of porous carbon nitride was prepared by pyrolysis of polymerized ethylenediamine using H-magadiite as the template. This material was characterized by XRD, FT-IR, XPS, and nitrogen sorption at 77 K. The BET surface area, pore volume and the median pore width are 436 m²/g, 0.69 cm³/g and 0.84 nm, respectively, based on the N₂ sorption. Using glass carbon electrodes modified by this material, an excellent linear determination range (0.05-0.99 μM) with a low detected concentration limit of 6.9 × 10^− 3 μM could be obtained on the determination of differential pulse voltammetries of dopamine in the presence of 400-fold excess of ascorbic acid.     

煤基活性炭孔径分布的调控

提出并研究了一种煤基活性炭孔径分布的调控方法及调控机理.将煤样与不同质量的KOH混合后炭化,分别对炭化料进行酸洗,以控制其中的钾含量,然后对酸洗料进行蒸汽活化,制成活性炭.通过对所制活性炭进行氮气吸附实验、扫描电镜及能谱分析和吸附能力表征实验后发现:改变KOH加入量和采用质量浓度为5%的盐酸对炭化料进行酸洗,能够改变炭化料中的钾含量;随着KOH含量的提高,活性炭的口发附能力逐渐增强,平均孔径从2.379 nm逐渐增大到2.636nm,同时孔径分布由以微孔为主逐渐向以中孔为主转移,其中孔含量由30.9%提高到46.1%.     

Short-period synthesis of ordered mesoporous silica SBA-15 using ultrasonic technique

Mesoporous silica SBA-15 was synthesized from rice husk ash via the ultrasonic technique in the hydrolysis-condensation stage. The effect of the time period in this stage on the mesoporous silica SBA-15 structure and physical properties was investigated and compared with those of the SBA-15 prepared by the conventional technique. It has been shown that the ultrasonic technique can be successfully applied for the synthesis of mesoporous silica SBA-15 with highly ordered hexagonal pore-arrangement and narrow PSD within the much shorter hydrolysis-condensation period. The SBA-15 products synthesized via the ultrasonic technique for the time period of 3 h have higher specific surface area, total pore volume, and microporosity than those prepared by the conventional technique for the time period of 24 h.     

Determination of the pore size distribution of correlated mesoporous networks

In the present work we study how the adsorption desorption hysteresis loop of a mesoporous disordered medium represented by a 3-dimensional Dual Site-Bond Model (DSBM) is affected by percolation. Site and bond distributions are assumed to be gaussians. The behavior of the threshold pressure for the evaporation processe suggests a method to determine the site and bond distributions from experimental adsorption-desorption hysteresis curves. Traditional methods developed for non-correlated networks are tested and evaluated against our simulation results showing the discrepancy mainly for highly correlated networks. Results of the prediction capability of our method are shown. Received: 30 March 2000     

Tuning the pore size and structure of mesoporous carbons synthesized using an evaporation-induced self-assembly method

Mesoporous carbons (MCs) have been prepared by the carbonization of reverse triblock copolymer-phloroglucinol/formaldehyde resin composites, which were themselves formed by hydrogen-bonding interaction through the evaporation-induced self-assembly method. The microstructure of MCs was analyzed by nitrogen adsorption isotherms and transmission electron microscope. The results showed that the pore size could be readily tailored from 4.7 to 17.8 nm by simply varying the weight ratios of formaldehyde and surfactants while the amounts of the other reactants were kept constant. The highest surface area and pore volume of MCs are 410 m²/g and 0.77 cm³/g, respectively. Moreover, the pore structure also can be controlled as ink-bottle or cylinder type.     

双电层电容器用中孔炭微球/活性炭复合电极的制备

采用水热法合成比表面积1850m2/g、粒径lμm的中孔炭微球(MCM);而后将所制MCM加入比表面积为3200m2/g的超级活性炭(HSAC)中制成用于双电层电容器的复合电极材料,并研究了该复合电极材料的电化学性能.结果表明:在比表面积为3200m2/g的HSAC中添加质量分数20%的MCM后,其颗粒接触内阻、离子扩散内阻明显降低;在6mol/L的KOH电解液体系中,在12A/g的电流密度下,其比电容仍能稳定在230F/g.而在同样的条件下,纯HSAC和纯MCM的比电容仅分别为190F/g和148F/g.复合电极在大电流下电化学性能的提高应归因于MCM合适的粒径、中孔结构及其较高的比表面积.     

Low temperature synthesis of crystalline mesoporous titania with high photocatalytic activity by post-treatment in nitric acid ethanol solution

Mesoporous titania powder with a bicrystalline (anatase and brookite) framework was prepared by modified sol-gel method using dodecylamine as template. The template could be easily removed by refluxing the powder in nitric acid ethanol solution. The effects of the acid treatment on the stability of inorganic framework were investigated. The samples were characterized by FT-IR, XRD, N₂ adsorption-desorption isotherms and HRTEM. The result showed that all of the as-prepared samples were wormhole-like mesoporous structure. The as-prepared sample showed a high photocatalytic activity to degrade Rhodamine B under UV-light irradiation, which was attributed to the porous structure, large BET surface area, bicrystalline, and small crystallite size.     

Preparation and characterization of hypercrosslinked resins with bimodal pore size distribution and controllable microporosity

Hypercrosslinked polystyrene resins with bimodal pore size distribution and controllable microporosity were prepared by combining traditional suspension polymerization and post crosslinking technique. The volume ratio of divinylbenzene (DVB) in monomer mixtures was kept at 20%, while vinylbenzyl chloride (VBC) concentration was progressively reduced to investigate effect of post crosslinking degree on the pore structure of the hypercrosslinked species. The results indicated that higher VBC concentration in monomer mixtures led to greater surface area, smaller average pore size and higher microporosity. Moreover, bimodal distribution of pore size could be observed for the final resins. The mesopore fraction should be derived from the pores originally present in precursor resins, while the micropore fraction was originated from the post crosslinking.     

Facile one-pot synthesis and drug storage/release properties of hollow micro/mesoporous organosilica nanospheres

Novel hollow micro/mesoporous organosilica nanospheres (HMOSNs) of uniform diameter and shell thickness of about 90 nm and 15 nm, respectively, and with wormlike micro/mesoporous shell full of uramido groups, have been successfully fabricated by a facile one-pot route. The micro/mesoporosity of the synthesized HMOSNs has been characterized by small-angle and wide-angle X-ray diffraction (XRD), scan electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption-desorption measurements. The drug storage and release properties of the synthetic HMOSNs are measured by using ibuprofen (IBU) as a model drug, and a high drug storage capacity of 531 mg IBU per gram HMOSNs and a steady drug release behavior are exhibited.     

Fabrication of Ni nanoparticles on ordered mesoporous carbon using an immersion-electrodeposition method

Ni nanoparticles have been fabricated on the surface of CMK-3 mesoporous carbon through an immersion-electrodeposition (IE) technique. Transmission electron microscopy analysis indicated that it was a facile approach to electrochemically prepare nano-sized Ni clusters. The electrocatalytic properties of Ni/CMK-3 nanocomposites electrode for hydrogen evolution reaction have been investigated by liner scanning voltammetry in alkaline solution, and high electrocatalytic activity was observed. Therefore, for the first time, we report this IE method as a new route to prepare metal/CMK-3 nanocomposites which have potential applications in the catalytic field.     

Efficient desulfurization of fuel with functionalized mesoporous carbon CMK-3-O and comparison its performance with mesoporous carbon CMK-3

In this work, a functionalized mesoporous carbon (CMK-3-O) was synthesized after oxidation with nitric acid and was used to adsorb dibenzothiophene (DBT) from model oil for the first time. Then, its performance was compared with that of CMK-3. The functionalized mesoporous carbon, CMK-3-O, showed better a capacitance performance for DBT adsorption than that of CMK-3. The maximum adsorption capacity was obtained for functionalized mesoporous carbon at optimum conditions with 6 M HNO₃ aqueous solution and 30 min contact time. The physical and structural properties of CMK-3-O and CMK-3 were investigated with X-ray diffraction method (XRD), N₂ adsorption–desorption isotherm, FT-IR, and elemental analysis (CHNO). Results of the elemental analysis showed that the oxygen and nitrogen content has increased and the carbon content has decreased through oxidation treatment. The effects of various factors on the adsorption process (such as temperature, amount of adsorbent, contact time, and concentration) of DBT were studied. CMK-3-O showed a maximum adsorption capacity of 86.96 mg DBT g^?1 of CMK-3-O at optimized conditions (temperature, 25°C; adsorbent dosage, 20 g L^?1; contact time, 60 min), which was a higher adsorption capacity of that observed for CMK-3 (57.47 mg DBT g^?1 of CMK-3). Kinetic studies have revealed that the adsorption of DBT can be described by a pseudo-second-order rate equation. Equilibrium data showed that adsorption process was best represented by the Langmuir model. The results also illustrated the fact that the regenerated adsorbent afforded 64.3% of the initial adsorption capacity after the two regeneration cycles.     

甘氨酸衍生的双介孔掺氮有序介孔炭用于超级电容器和氧气还原

掺氮多孔炭材料在电化学能量储存和转化方面具有良好的应用前景.可控的氮原子掺杂与孔结构设计对提高其性能起着重要作用.本工作利用无溶剂纳米铸造法,以甘氨酸(Gly)为单一前驱体、以SBA-15为硬模板,制备了掺氮有序介孔炭材料(N-OMCs).甘氨酸在SBA-15孔道内的限域热解对提高碳产率、氮掺杂量以及构筑双介孔结构非常...     

双模板结构导向剂制备有序介孔炭

以间苯二酚/甲醛制备的酚醛树脂为碳前躯体,三嵌段共聚物F127和P123作为主辅结构导向剂,采用有机-有机自组装的方法制备有序介孔炭(Ordered mesoporous carbons,简称OMCs)。采用X射线衍射仪、透射电镜和N2吸/脱附手段对所制OMCs进行表征,研究了反应时间以及主辅模板剂的比例对介孔孔道结构的影响。结果表明,随着反应时间从24h延长至72 h,介孔炭有序性先增后减;当主辅模板剂F127/P123摩尔比为0.002 7∶0.002 7时,所得介孔炭有序性较好,为P6mm型孔道结构,介孔孔容和比表面积分别为0.59 cm3/g和640.34 m2/g,平均孔径为3.68 nm.     

特定孔径分布活性炭的制备及电容性能研究

在酚醛树脂中掺杂二茂铁可制得特定孔径分布的活性炭,炭化样品孔径主要在 3~4nm 之间分布,双层容量高达 0.26F/m2。水蒸气活化不同时间,树脂炭在10~20nm之间有较大孔容产生,同时比表面积增加。炭化样品碳含量高,但活化后,随碳氢含量的降低,结构破坏,双层容量降低。