用于PEMFC的介孔碳担载铂氧化钨电催化剂的制备与表征

利用介孔碳作为载体,制备介孔碳担载Pt-WO3复合催化剂应用于质子交换膜燃料电池（PEMFC）电极.以苯为碳源,采用气相沉积法复制介孔SiO2Al-SBA-15模板结构合成石墨化介孔碳Cg,采用浸渍法制备无定形介孔碳CMK-3.通过分步沉积,将Pt和WO3担载到介孔碳载体上,采用比表面分析（BET）、X线衍射（XRD）、透射电子显微镜（TEM）、循环伏安法以及单电池极化性能测试对介孔碳担载的复合催化剂进行表征.结果表明：介孔碳作为催化剂载体,其孔道结构有助于催化剂的均匀分散,从而提高催化剂的电催化剂活性.由于石墨化介孔碳的导电性能高于无定形介孔碳,因此Pt-WO3/Cg比Pt-WO3/CMK-3具有更好的电极催化活性.     

介孔碳吸附亚甲基蓝的热力学和动力学研究

以3种介孔碳CMK-3、立方Ia3d结构介孔碳和层状介孔碳MMC为吸附剂,考察了它们对亚甲基蓝的吸附效果;利用Langmuir和Freundlich吸附等温模型来描述3种介孔碳对亚甲基蓝的吸附行为,Langmuir等温模型的拟合性更好;利用准1级和准2级动力学模型考察吸附动力学,3种介孔碳吸附亚甲基蓝的动力学曲线更符合准2级动力学模型,吸附速率常数分别为0.007 3、0.002 0、0.004 8 g/(mg·min),且均是单分子层的物理作用;3种介孔碳中CMK-3对亚甲基蓝的吸附量最高,为3.067 g/g。     

Pd/CMK-3催化加氢制备邻氨基苯酚研究

采用浸渍还原法在CMK-3介孔炭上负载Pd制备Pd/CMK-3催化剂,考察了Pd/CMK-3水相催化加氢邻硝基苯酚钠制备邻氨基苯酚钠的催化性能。结果表明:当Pd负载量为5%,反应温度为338 K,反应压力为1 MPa时,邻硝基苯酚钠的转化率达到100%,邻氨基苯酚钠的选择性高于99.5%,邻氨基苯酚收率为98.0%。采用XRD、BET、SEM和TEM对于催化剂进行了表征,结果表明:CMK-3具有良好的介孔结构以及较高的比表面积,Pd纳米颗粒在CMK-3表面高度分散且具有较好稳定性,因此具有更高的催化加氢活性。     

磺酸化碳材料负载Ru催化剂催化纤维素水解/加氢反应

采用纤维素衍生碳、活性炭和介孔碳材料CMK-3为不同碳源前驱体,在不同磺酸化条件下制备磺酸化碳材料负载Ru的双功能催化剂,并用FTIR光谱、XRD、元素分析、热重分析、N₂物理吸附 脱附进行了表征,考察了其对纤维素加氢反应的催化活性。结果表明：相比于纤维素衍生化碳,活性炭和介孔碳CMK-3为碳源经过磺酸化后制备的催化剂具有较强的结合-SO₃H的能力和较高的催化活性,对多元醇具有良好的选择性,170 ℃下反应10 h六元醇的收率可高达84.0%。在循环使用时,磺酸化活性炭负载Ru催化剂催化活性有所降低,但可以保持对多元醇的选择性;而磺酸化介孔碳负载Ru催化剂存在少量S流失,转化率基本不变,但产物的选择性有所降低。     

有序介孔碳对低浓度气相萘的吸附特性分析

对3种常见有序介孔碳（OMCs）吸附脱除典型气相多环芳烃--萘进行了研究。分别采用吸附等温线模型（Langmuir、Freundlich、Sips）和恒定浓度波动力学模型对吸附等温线和穿透曲进行拟合分析。采用程序升温脱附法通过失重曲线分析了吸附剂的再生性能。结果表明：Langmuir模型和Sips模型能很好地描述低浓度气相萘在OMCs上的静态吸附行为（R² > 99%），吸附量呈CMK-5 > CMK-3 > FDU-15排列。恒定浓度波动力学模型具有较高的拟合度，介孔促使3种吸附剂对萘分子具有较高的吸附扩散系数。具有微通孔结构的CMK-5和FDU-15表现出更好的再生性能。综合吸脱附动力学分析，CMK-5在3种吸附剂中表现出更好的应用潜能。     

聚丙烯腈/有序介孔碳复合材料吸附铀(VI)的性能研究

本文以CMK-3为主体,将其与丙烯腈单体进行自由基聚合,制备出聚丙烯腈/有序介孔碳复合材料(PAC/CMK-3)。采用TEM、SEM、N2吸附-脱附曲线对复合材料进行表征。系统研究了溶液p H值、初始浓度、反应时间、温度等因素对铀(VI)吸附性能的影响。结果表明,PAC/CMK-3在p H值为5.0时对铀(VI)的吸附能力最高,吸附平衡时间为25 min。相比于CMK-3,复合材料单分子层饱和吸附量由40.90 mg/g增长至220.01 mg/g。     

有序介孔碳-石墨烯复合材料的制备及其对银纳米粒子吸附性能的研究

以溶剂挥发诱导有机-有机自组装法制备了有序介孔碳-石墨烯（OMC-RGO）复合材料。结果表明：当焙烧温度为800℃时,所得的OMC-RGO复合材料与OMC相比,其电导率从0.76S/m增加到32.5S/m,提高到42.8倍;但BET比表面积和孔容分别从670m2/g和0.40cm3/g下降到361m2/g和0.23cm3/g,降低的比率分别为46.1%和42.5%。随后,我们以OMC-RGO为载体,通过物理吸附制备了有序介孔碳-石墨烯-银纳米粒子（OMC-RGO-Ag）复合材料。结果表明：OMC-RGO表面上Ag纳米粒子的粒径在20～40nm之间;且OMC与RGO复合后,RGO表面上的含氧官能团有利于吸附较多的Ag纳米粒子。     

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。     

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。     

酚醛树脂对介孔碳孔结构及有序性的影响

以酚醛树脂为碳前体,三嵌段聚合物F127作为模板剂,采用溶剂挥发自组装法制备了有序介孔碳材料。采用凝胶渗透色谱测定了不同合成温度酚醛树脂的分子量;使用X射线衍射、透射电镜和N2吸/脱附等手段对有序介孔碳进行了表征。研究了合成酚醛树脂的温度对介孔碳孔径分布及有序性的影响。结果表明,随着合成酚醛树脂的温度从75℃升到95℃,介孔碳的有序性先增后减:酚醛树脂的合成温度为85℃时,所得介孔碳有较好的有序性,介孔孔容和比表面积分别为0.115cm3/g和127m2/g,平均孔径为3.41nm。     

Synthesis of recyclable catalyst-sorbent Fe/CMK-3 for dry oxidation of phenol

The magnetic mesoporous material Fe/CMK-3 acting as a catalyst-sorbent was synthesized by using ordered mesoporous carbon CMK-3 as the supporter, Fe(NO₃)₃ as the iron source, and glycol as the reducing agent. The samples synthesized were characterized by powder X-ray diffraction (XRD), N₂ adsorption-desorption, scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results show that the prepared Fe/CMK-3 preserved the ordered mesoporous structure of CMK-3, and magnetic species was mainly Fe₃O₄, which was dispersed inside channels of CMK-3 as nanoparticles with the diameter of around 10 nm. The adsorption and catalytic dry oxidation efficiency of the prepared Fe/CMK-3 were determined. The results also show that Fe/CMK-3 had good adsorption performance of phenol in aqueous solution and could be easily separated from water and recycled due to its ferromagnetic nature. Iron oxides supported on CMK-3 were excellent catalysts for dry oxidation of phenol. After 15 adsorption-catalytic oxidation cycles, the phenol adsorption capacity of Fe/CMK-3 only decreased a little, suggesting the good practicality. Combined thermogravimetry and mass spectrum (TG-MS) instrument was used to investigate the catalytic oxidation of phenol on Fe/CMK-3 and the ignition characteristics of the catalyst-sorbent. The supported Fe₃O₄ was found to be not only the magnetic component but also the active catalyst for the oxidation of phenol. The adsorbed phenol could be oxidized into CO₂ and H₂O at 220 °C at which no obvious phenol desorption or CMK-3 ignition occurred.     

Catalytic ammonia decomposition over CMK-3 supported Ru catalysts: Effects of surface treatments of supports

CMK-3 carbon was used as a catalyst support for Ru catalyst for ammonia decomposition. The supports were treated with acid, and the effects of treatment on the properties of CMK-3 supports were studied by N₂ adsorption, XRD, XPS and mass titration. The chemical treatment of carbon support cause significant changes in carbon surface chemistry and in turn had significant effects on both catalyst dispersion and catalytic activity. It is found that the as-synthesized CMK-3 carbon is not a good catalyst support for this reaction. However, surface functional groups produced by acid treatments led to larger Ru catalyst particles, while alkali treatments made the Ru catalyst dispersion even worse due to the residue alkali or earth alkali metals. Interestingly, relatively larger Ru catalyst particles but still well dispersed in the channel of the mesoporous structures of the carbon improves NH₃ conversion into H₂. This is determined by the chemical reaction rate-limiting step of ammonia decomposition. The catalytic activity follows the order: Ru-K/CMK-3 > Ru-Na/CMK-3 > Ru-Ca/CMK-3 > Ru-Cl/CMK-3 > Ru-SO₄/CMK-3 > Ru-PO₄/CMK-3 > Ru/CMK-3 > Ru-Li/CMK-3. CMK-3 is not a good carbon catalyst support due to its amorphous structure resulting in the poor electron conductivity.     

Hydrogen production from catalytic decomposition of methane over ordered mesoporous carbons (CMK-3) and carbide-derived carbon (DUT-19)

This paper presents a thermogravimetric analysis of catalytic methane decomposition using ordered mesoporous carbon nanorods (CMK-3) and ordered mesoporous carbide-derived carbon (DUT-19) as catalysts. X-ray diffraction and N₂ physisorption analyses were performed for both fresh catalysts. Threshold temperatures for methane decomposition with DUT-19 and CMK-3 were estimated by three different methods found in literature. Carbon formation rate and carbon weight gain as a function of time at various temperatures and methane partial pressures were studied, and the kinetics of CMK-3 and DUT-19 as catalysts for methane decomposition were investigated. Arrhenius energy values of 187 kJ/mol for CMK-3 and 196 kJ/mol for DUT-19 with a reaction order of 0.5 were obtained for both catalysts. Results show that carbon deposition on the catalyst during the reaction lead to catalyst deactivation with significant surface modification. Scanning electron microscope studies of fresh and deactivated catalyst samples show the blocking of catalyst pores and the formation of agglomerates on the outer surface of the catalyst during the course of reaction. DUT-19 catalytically outperforms CMK-3 because of a lower threshold temperature, higher surface area, and higher pore volume. These results show that ordered mesoporous carbons are promising catalysts for methane decomposition.     

Indoor formaldehyde removal over CMK-3

The removal of formaldehyde at low concentrations is important in indoor air pollution research. In this study, mesoporous carbon with a large specific surface area was used for the adsorption of low-concentration indoor formaldehyde. A mesoporous carbon material, CMK-3, was synthesized using the nano-replication method. SBA-15 was used as a mesoporous template. The surface of CMK-3 was activated using a 2N H₂SO₄ solution and NH₃ gas to prepare CMK-3-H₂SO₄ and CMK-3-NH₃, respectively. The activated samples were characterized by N₂ adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy. The formaldehyde adsorption performance of the mesoporous carbons was in the order of CMK-3-NH₃ > CMK-3-H₂SO₄ > CMK-3. The difference in the adsorption performance was explained by oxygen and nitrogen functional groups formed during the activation process and by the specific surface area and pore structure of mesoporous carbon.     

A simple method to synthesize graphitic mesoporous carbon materials with different structures

Graphitic mesoporous carbon materials with different structure were synthesized by reversed replication method. SBA-15 was used as hard template and the synthesized aromatic polymers with different polymerization degree as the carbon sources. Adopting the impregnation method, the carbon source was assembled into the pore of the SBA-15. The silica/aromatic polymers system was carbonized under N₂ atmosphere (high polymerization degree aromatic polymers) and vacuum (low polymerization degree aromatic polymers) to produce the graphitic mesoporous carbon materials with structure of CMK-3 and CMK-5, respectively. It is a easy way to synthesize the graphitic mesoporous carbon materials, especial for the CMK-5 structure. The porous structure and composition of these carbon materials were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectrometry, and N₂ adsorption–desorption measurements.     

Characterization and catalytic performance of poly(4-vinylpyridine) supported on mesoporous carbon: comparison with poly(4-vinylpyridine) supported on mesoporous silica

In this study, the synthesis of poly(4-vinylpyridine) (P4VP) supported on mesoporous carbon (CMK-3) by in situ polymerization of 4-vinylpyridine in the presence of CMK-3 has been investigated. The structural properties of the P4VP/CMK-3 were investigated by FT-IR, XRD, BET, TGA, SEM and TEM techniques. The catalytic activity of this new heterogeneous basic catalyst was tested for Knoevenagel reaction. Excellent yields at room temperature in aqueous media and solvent-free conditions were obtained. The catalytic activity of this purely organic hybrid catalyst was compared with P4VP/SBA-15 to clarify the advantages of mesoporous carbon on mesoporous silica as support. The results showed that the stability of P4VP/CMK-3 was excellent and could be reused 10 times without much loss of activity in Knoevenagel reaction. Surprisingly, the composite prepared by mesoporous carbon showed much higher activity than that of P4VP/SBA-15. This unique result opens new perspectives for application of mesoporous carbons as structurally defined hydrophobic catalyst support in catalytic reactions.     

Synthesis of polyaniline/mesoporous carbon nanocomposites and their application for CO<Subscript>2</Subscript> sorption

Ordered mesoporous carbons (OMC), were synthesized by nanocasting using ordered mesoporous silica as hard templates. Ordered mesoporous carbons CMK-1 and CMK-3 were prepared from MCM-48 and SBA-15 materials with pore diameters of 3.4 nm and 4.2 nm, respectively. Mesoporous carbons can be effectively modified for CO₂ adsorption with amine functional groups due to their high affinity for CO₂. Polyaniline (PANI)/mesoporous carbon nanocomposites were synthesized from in-situ polymerization by dissolving OMC in aniline monomer. The polymerization of aniline molecules inside the mesochannels of mesoporous carbons has been performed by ammonium persulfate. The nanocomposition, morphology, and structure of the nanocomposite were investigated by nitrogen adsorption-desorption isotherms, Fourier Transform Infrared (FT–IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and thermo gravimetric analysis (TGA). CO₂ uptake capacity of the mesoporous carbon materials was obtained by a gravimetric adsorption apparatus for the pressure range from 1 to 5 bar and in the temperature range of 298 to 348 K. CMK-3/PANI exhibited higher CO₂ capture capacity than CMK-1/PANI owing to its larger pore size that accommodates more amine groups inside the pore structure, and the mesoporosity also can facilitate dispersion of PANI molecules inside the pore channels. Moreover, the mechanism of CO₂ adsorption involving amine groups is investigated. The results show that at elevated temperature, PANI/mesoporous carbon nanocomposites have a negligible CO₂ adsorption capacity due to weak chemical interactions with the carbon nanocomposite surface.     

Preparation of mesoporous silica replica using ordered mesoporous carbon by vapor phase transport of silica source

A new vapor phase transport (VPT) technique to prepare an inverse silica replica of an ordered mesoporous carbon was developed. Tetraethyl orthosilicate (TEOS) was infiltrated in mesoporous carbon CMK-3 as the hard template at 180 °C for 48 h under an autogenous pressure in an autoclave in the presence of water. The samples obtained by removal of CMK-3 retained structural regularity of CMK-3 with little shrinkage of framework, which were characterized by SAXRD, N₂ adsorption, TG-DTA, and SEM. Influence of preparation temperature on the loading amount of silica was investigated. The multi-step replication process was monitored by characterizing the replicated materials as well as intermediate composites.     

The Adsorption of Gold,Palladium, and Platinum from Acidic Chloride Solutions on Mesoporous Carbons

Studies on the adsorption characteristics of gold, palladium, and platinum on mesoporous carbon (CMK-3) and sulfur-impregnated mesoporous carbon (CMK-3/S) evaluated the benefits/drawbacks of the presence of a layer of elemental sulfur inside mesoporous carbon structures. Adsorption isotherms collected for Au(III), Pd(II), and Pt(IV) on those materials suggest that sulfur does enhance the adsorption of those metal ions in mildly acidic environment (pH 3). The isotherms collected in 1 M HCl show that the benefit of sulfur disappears due to the competing influence of large concentration of chloride ions on the ion-exchanging mechanism of metal ions sorption on mesoporous carbon surfaces. The collected acid dependencies illustrate similar adsorption characteristics for CMK-3 and CMK-3/S in 1-5 M HCl concentration range. Sorption of metal ions from diluted aqueous acidic mixtures of actual leached electronic waste demonstrated the feasibility of recovery of gold from such liquors.     

Easy synthesis of an ordered mesoporous carbon with a hexagonally packed tubular structure

Ordered mesoporous carbon with hexagonal arrays of tubes (CMK-5) was successfully synthesized via a nanocasting process by directly using SBA-15, instead of AlSBA-15, as a template, furfuryl alcohol as a carbon source and oxalic acid as the catalyst. The time consuming impregnation of SBA-15 with aluminum could be saved. The as-synthesized CMK-5 exhibits a tubular structure with double pore system. The loading amount of carbon precursor on the pore walls of SBA-15 is the key factor for the formation of the CMK-5 structure with two-dimensional hexagonal arrays of tubes, and the pore diameter can be adjusted by varying the loading amount of the carbon precursor. The CMK-5 carbon exhibits high apparent surface area up to ∼2500 m²/g and high pore volume reaching ∼2 cm³/g, which is due to the unique structure of CMK-5. The characterization results confirmed that carbonization under argon atmosphere instead of vacuum is sufficient for the structural formation of CMK-5 carbons, and can be used as an alternative pathway to prepare tubular-type carbons.