有序介孔碳材料的模板化构筑及水处理应用研究

介孔碳材料是指孔径介于2 nm-50 nm的一类多孔碳材料。有序介孔碳材料，具有比表面积高、孔道结构规则有序、孔径分布狭窄、孔径大小可调控、表面易于修饰等结构特点和高机械强度、强吸附能力、化学惰性等性能特点，在诸多领域得到了广泛应用，特别是其作为新型吸附剂在水处理领域具有广阔的发展前景。有序介孔炭材料的制备方法主要有硬模板法和软模板法。模板和碳源的选择是控制有序介孔碳材料结构和性能的关键因素。本文从有序介孔硅、天然矿物、MOFs材料、嵌段共聚物等不同模板的角度对有序介孔碳、多级有序微/介孔碳、多级有序大/介孔碳的制备方法进行综述，并对有序介孔碳材料在水处理领域的应用进行简单介绍。     

Fabrication of new ordered mesoporous carbons from petroleum pitch by triblock copolymer direct templating method

A highly ordered mesoporous carbon nanocage (OMC) direct synthesis method is introduced in this article. Petroleum pitch is chosen as a hydrophobic carbon precursor, tetrahydrofuran (THF) is used as solvent, the triblock copolymer F127 as structure directing agent, while the liquid crystal templating (LCT) is used as the templating mechanism, and the OMC was obtained via a one-step nanocasting method. Experimental results showed that the introduction of proper amounts of petroleum pitch and THF ratio does not hamper the synthetic process of the structure of OMC, thus a uniform carbon composite is finally formed. It was found that the as-prepared nanoporous carbon has a three-dimensional 7.5 nm-sized carbon nanocage network. Such a uniform mesoporous carbon material exhibits a high Brunauer–Emmett–Teller (BET) surface area (446.9 m² g^??1) and a total pore volume (0.6 cm³ g^??1).     

软模法磁性有序介孔炭的合成与表征

以三嵌段共聚物为软模,间苯二酚-甲醛为炭前躯体,硝酸铁为铁源合成了磁性有序介孔炭,用XRD、氮气吸附、磁性测试等方法对样品进行表征.结果表明,当硝酸铁与间苯二酚摩尔比为0.025、0.05及0.10时得到的介孔炭具有有序性,随着铁质量分数的增加,有序性降低,比表面积、孔容都相应减小.基本磁化曲线结果表明,随着铁质量分数的增加,饱和磁化强度随之增加(0.01～0.10 emu/g),材料具有较好的磁性,容易从溶液中分离,表现出良好的分离性能.为磁性有序介孔炭的优化合成及磁性分离应用提供科学依据.     

Preparation of the anatase/TiO2(B) TiO2 by self-assembly process and the high photodegradable performance on RhB

The TiO₂ samples, synthesized with different addition amount of titanium source, have been prepared by a bottom-up method employing inverse lamellar micelles as the template in a surfactant molecular self-assembly process. The products were characterized by X-ray diffraction (XRD), Raman, Field-emission scanning electron microscope (FESEM), Transmission scanning electron microscopy (TEM), X-ray photoelectron Spectroscopy (XPS), Nitrogen adsorption-desorption isotherms, Photoluminescence spectra (PL), UV–vis diffuse reflectance (DRS) and photodegradable tests. The results show that all samples are biphases TiO₂ (anatase and TiO₂(B)). In addition, with the increment of titanium source, the microstructure of three samples have changed from small 3D aggregates to big 3D aggregates composed of 2D nanosheets, and the proportion of the anatase phase in three products and the specific surface area (BET) of the samples gradually increased, which not only can suppress the recombination of photogenerated electrons and holes, and can also enhance the photodegradable performance and the adsorption performance of three products on organic pollutants RhB. The 2.5-TiO₂ Ss exhibited the best photodegradable performance among three samples. Meanwhile, the 2.5-TiO₂ Ss also had a good cycle stability and low performance loss (8%).     

有序介孔TiO2材料的合成、表征与应用

有序介孔材料是近年来新兴起的一个研究热点,非硅基有序介孔材料在光催化、磁、电等诸多领域存在巨大的潜在应用价值.而TiO2以其特有的光催化活性、紫外光屏蔽效应等功能,以及化学性质稳定、毒性低、价格便宜和易于回收等特点,尤其值得关注.笔者综合阐述了有序介孔TiO2材料的合成过程、合成机理以及材料的表征和应用前景等情况.     

Wormhole-like mesoporous magnesium oxide fabricated by surfactant templating method to enhance cycling performance of lithium-sulfur batteries

Lithium-sulfur (Li–S) batteries are considered to have the best development prospect for electric vehicles. But enhancing the cycling performance of Li–S batteries is necessary and urgent. Mesoporous MgO particles (MMgO) are prepared by surfactant templating method and used to prepare cathode materials for the first time. The prepared MMgO has a hexagonal flake-like structure with a thickness of 50–80 nm, a transverse length of 150–350 nm, a processing area of 181.56 m²/g, an average pore diameter of 3.11 nm and a pore volume of 0.26 cc/g. MMgO shows low intensity and slightly broader diffraction peaks in the XRD pattern, indicating the presence of lattice distortion, defects, dislocations or unsaturated valence bonds. MMgO particles are uniformly distributed on the sulfur surface to provide high surface area, many active sites and interconnected channel structure, which makes more sulfur contact with MMgO to be adsorbed, activated and participated in charge and discharge reaction. The Li–S battery containing sulfur/MMgO composite at weight ratio 90:10 shows the best cyclic stability with capacity retention rate 84.7% after 100 cycles at 0.2 C. The initial specific capacity of a Li–S battery with sulfur/MMgO composite at weight ratio 70:30 can reach 1062 mAh/g at 0.2 C, which is much higher than sulfur/commercial MgO at the same weight ratio.     

A novel approach to mesoporous anatase TiO2: Oxidation of TiC by nitric acid

TiO₂ has been prepared by a novel, mild one-step reaction between TiC and aqueous HNO₃ at 70 °C. This material possesses an anatase crystal form and a narrow pore-size distribution of mesoporous channels. The BET surface area, average pore diameter, and total pore volume are 332.7 m²/g, 3.28 nm, and 0.23 cm³/g, respectively. Our method is a template-free synthesis process, distinct from sol–gel methods for mesoporous TiO₂ fabrication using structure-directing surfactants or polymers. TiO₂ is not generated from TiC reacting with other acids and oxidants, such as HCl, H₂SO₄, H₃PO₄, KMnO₄, K₂Cr₂O₇, Na₂S₂O₇, H₂O₂, and Na₂CrO₄, at a similar reaction condition. Since the average particle size of the mesoporous TiO₂ produced is much larger than that of the TiC starting material, the mechanism for the formation of the mesoporous TiO₂ is not via mesopore-etching of TiC particles and transformation of TiC pore walls into TiO₂ by HNO₃. It is likely that TiC is first transformed into Ti_mX_n species, followed by hydrolysis to form mesoporous TiO₂.     

溶胶-凝胶模板法制备三维有序大孔TiO_2微球

采用无皂乳液聚合方法自制的单分散聚苯乙烯(PS)微球乳液为原料,并以PS微球自组装制备了有序胶体晶体模板("蛋白石"),采用溶胶-凝胶模板法制备了三维有序大孔TiO2微球("反蛋白石"),其孔呈六边形,孔径分布均一,约为200 nm,运用SEM,XRD对其形貌特征及晶型进行表征。结果表明,采用表面含有羧基的单分散聚苯乙烯微球及高的硅油粘度制得的模板有序度高;控制煅烧温度可以改变有序大孔TiO2微球的晶型,当煅烧温度为500℃时,其晶型为锐钛型,当煅烧温度为700℃时,其晶型则为金红石型。     

软模板法合成有序介孔材料的研究进展

有序介孔材料具有高度有序的孔道结构,较高的比表面积和较多活性位,已经广泛应用于气体吸附、催化剂和功能材料等领域。本文系统评述了软模板法制备有序介孔材料的合成路线及其组装机理,并对课题组采用软模板法组装介孔氧化钛粒子的机理进行了分析。     

Preparation of ordered mesoporous carbon membranes by a soft-templating method

Preparation of continuous mesoporous carbon membranes without the use of an intermediate inorganic template was achieved using a thermosetting phenolic resin, resorcinol/phloroglucinol/formaldehyde, and a thermally-decomposable organic template, Pluronic F127 (PEO₁₀₆–PPO₇₀–PEO₁₀₆). The coating solution was cast on porous α-alumina supports by dip-coating. Afterwards, decomposition of the organic template and solidification of the carbon precursors are simultaneously performed through a carbonization process. A composite layer of carbon/alumina was formed. The single gas permeation was governed by the Knudsen diffusion mechanism. The membrane exhibited high hydrothermal stability and high alkaline resistance.     

熔盐法合成有序介孔碳负载的金属碳化物

有序介孔碳是一种具有宽孔径、规则孔道结构、高比表面积和大孔容的纳米结构材料,具有很高的导电性及化学稳定性,是一种非常优良的载体材料。过渡金属碳化物因其结构相似性,具有一系列类似贵金属的性质,可作为贵金属替代材料,用于多相催化过程。但过渡金属碳化物多数粒径大、比表面积低,不利于催化活性,因此,采用熔盐法合成了多种有序介孔碳负载的过渡金属碳化物,并通过SEM、TEM、XRD、BET等方法对样品进行了一系列表征。结果表明,该方法能有效制备碳负载的TiC、Mo₂C等金属碳化物,且具有较小的颗粒尺寸和较高的比表面积,将有较好的催化应用前景。     

Synthesis of mesoporous niobium oxophosphate using niobium tartrate precursor by soft templating method

Mesoporous niobium oxophosphate (NBP) with high specific surface area (427 m²/g) and narrow pore size distribution (3–15 nm) has been prepared using aqueous solution of niobium tartrate complex, diammonium hydrogen phosphate as precursors and cationic surfactant, tetradecyl trimethylammonium bromide (TTBr) as an organic template. The synthesized material has been characterized by simultaneously recorded thermogravimetric and differential thermal analysis (TG–DTA), fourier transformed infrared spectroscopy (FTIR), high and low angle X-ray diffraction (XRD), N₂ adsorption–desorption isotherms, high resolution transmission electron microscopy (HRTEM), ³¹P solid state magic angle spinning nuclear magnetic resonance (³¹P MASNMR) spectroscopy and energy dispersive X-ray (EDX) analysis. HRTEM and XRD confirm the formation of mesoporous structure and HRTEM image indicates the formation of wormhole-like mesopores in the synthesized sample. The interaction of pyridine with niobium oxophosphate has been investigated by means of adsorption infrared spectroscopy (FTIR) which shows that both Brönsted and Lewis acid sites are present on the surface of niobium oxophosphate.     

锐钛型TiO2对尿素热解过程的影响

通过实验的方法收集了不同温度下纯尿素和尿素/TiO₂混合物热解后的固体残留物，使用红外光谱（IR）及气相色谱质谱联机（GC-MS）方法对这些热解残留物进行成分分析；使用热重-红外联机（TG-FTIR）技术研究尿素及三聚氰酸在有无催化剂TiO₂的情况下的热解特性及气体产物的生成规律；根据Coats-Renfern方法对尿素热解第一阶段的非等温热失重率曲线的数据进行动力学研究，建立动力学方程。结果表明，100~250℃的尿素热解残留物中主要为尿素和缩二脲，300~400℃的尿素热解残留物中主要为三聚氰酸等含氮杂环有机化合物；锐钛型TiO₂能促进尿素和三聚氰酸的热解反应，缩短其反应进程，HNCO与水蒸气在TiO₂表面易发生反应；尿素第一阶段热解的反应级数为2，单独热解时活化能为113.25kJ/mol，指前因子A为2.01×10¹¹min^-1，在催化剂TiO₂的作用下，活化能E为77.42kJ/mol，指前因子A为4.82×10⁷min^-1。     

蒸发诱导自组装法合成介孔铝酸钴尖晶石

采用嵌段聚合物F127为表面活性剂,以硝酸铝和硝酸钴为无机先驱物,通过蒸发诱导自组装的方法合成了介孔结构的铝酸钴尖晶石。X射线衍射（XRD）表明样品具有单一的尖晶石型结构。利用氮气吸附-脱附比表面测定仪测得不同焙烧温度样品的比表面积和孔径,发现650 ℃焙烧的样品比表面积最大,为89.1 m2/g,孔径为 8.7 nm。通过紫外-可见光谱测定表明介孔铝酸钴样品为明亮的蓝色,在545、585、625 nm处有3重吸收峰。     

简易模板法制备有序介孔碳及其表征

目前制备有序介孔碳的方法工艺复杂、繁琐耗时,为了简化其制备工艺,缩短实验流程,本文提出一种不需要添加额外溶剂直接制备有序介孔碳的方法。以三嵌段共聚物F127为模板剂,自制低分子量酚醛树脂为碳前体,制备了具有二维六方结构的介孔碳。采用红外光谱对酚醛树脂和F127进行表征,研究了两者之间的作用力;采用X射线衍射、透射电镜和N2吸附/脱附等手段对介孔碳结构进行表征,研究了酚醛树脂的合成温度和模板剂用量对介孔碳结构的影响。结果表明酚醛树脂合成温度为70℃,F127：PF=1时,得到的介孔碳比表面积、孔容和孔径分别为490m2/g、0.41cm3/g和4.15nm。     

Preparation and characterization of three-dimensional ordered macroporous ZrO2 by two-step templating process

Three-dimensional ordered macroporous (3DOM) ZrO₂ materials were prepared by using 3DOM carbon materials as templates and ZrOCl₂ solution as precursor. 3DOM carbon materials were first prepared by using SiO₂ templates and traditional colloidal crystal templating process, then ZrOCl₂ solution used as zirconium source was infiltrated into the structure of 3DOM carbon and solidified. Finally, 3DOM carbon materials were removed through sintering process and 3DOM ZrO₂ materials were obtained. The microstructures of obtained samples were studied by scanning electron microscope (SEM), transmission electron microscope (TEM) with energy dispersive spectrometry (EDS), and X-ray diffraction (XRD) analysis. The final macroporous ZrO₂ could successfully replicate the 3DOM structure of carbon and had less than 5% shrinkage. The result indicates that 3DOM carbon could be efficiently used as two-step templated materials and obtained 3DOM ZrO₂ had a very small shrinkage.     

Effects of PEG templating of spray-pyrolyzed TiO2 films on their nanoscale roughness and eventual photoelectrochemical properties

Journal of Applied Electrochemistry - This paper reports the effects of polyethylene glycol (PEG) as a morphological template for spray-pyrolyzed TiO2 films. The virtues of PEG-modified TiO2 films...