Pd/CMK-3的合成及其在Suzuki-Miyaura碳-碳偶联反应中的应用

利用介孔二氧化硅（SBA-15）为模板、蔗糖为碳源,制备了有序介孔碳材料CMK-3,然后以CMK-3为载体,利用浸渍还原法得到介孔碳负载Pd纳米粒子的复合催化剂（Pd/CMK-3）,通过XRD、TEM以及氮气吸附-脱附等手段对催化剂的微结构和组分进行分析,结果表明CMK-3为有序介孔结构,孔径约为5nm,Pd/CMK-3保留了介孔结构,且孔道中负载有不同尺寸的Pd粒子。应用于无配体催化的Suzuki-Miyaura相似文献   

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 ordered mesoporous SiCN ceramics with large surface area and high thermal stability

For the first time, highly ordered two-dimensional (2-D) and three-dimensional (3-D) mesoporous SiCN ceramics with high surface area and high thermal stability were prepared by nanocasting a preceramic polymer solution into mesoporous carbon templates, CMK-3 and CMK-8, respectively. As a negative replica of CMK-3 carbon, the obtained mesoporous SiCN ceramic possessed an ordered 2-D hexagonal mesostructure, which is similar to the structure of SBA-15 silica except for the reduced dimensions. An ordered 3-D cubic mesoporous SiCN ceramic was also fabricated using CMK-8 as a template. The wall of the mesoporous SiCN replicas consisted of an amorphous SiCN ceramic phase, which possessed high thermal stability at high temperature up to 1000 °C. N₂-sorption isotherms revealed that these ordered mesoporous SiCN ceramics have high BET surface areas (up to 472 m² g⁻¹) and narrow pore-size distributions, which was preserved even after a re-treatment at 1000 °C in air. The use of carbon template played an important role in the preparation of mesoporous SiCN replicas and enhanced the thermal stability of the SiCN products. It is expected that many other types of ordered mesoporous ceramics can be prepared from nanoporous carbon by nanocasting method.     

Synthesis and characterization of hybrid nano-crystallites inside self-ordered mesoporous carbon

The design and construction of nano-crystallites inside ordered mesoporous carbon is of great interest for potential applications in many fields. One of the main challenges is how to control hybrid nano-crystallites formed inside the pores. We describe a synthesis strategy of impregnation/hydrothermal method for incorporation of hybrid nano-crystallites Ru_0.3Cr_0.7O₂ inside CMK-3 with the average size of the nano-crystallites around 2.8–3.05 nm. The texture/structures of the resultant materials have been characterized by X-ray diffraction, transmission electron microscope, and nitrogen adsorption/desorption measurements. No nano-crystallites are observed to be generated on the external surface of CMK-3. The resultant material exhibits a high specific capacitance of approximately 226 F g⁻¹. This approach is expected to be applied to other hybrid metals oxides synthesized inside CMK-3 with specific structures and properties. Furthermore, it provides a versatile route for expanding the application of ordered mesoporous carbon with diverse pore arrangements.     

Carbon nanocage: a large-pore cage-type mesoporous carbon material as an adsorbent for biomolecules

Novel large pore cage type mesoporous carbons, carbon nanocages, abbreviated as CKT (carbon from KIT-5) using three dimensional large cage type face centered cubic Fm3m mesoporous silica materials (KIT-5) as inorganic templates prepared at different temperature were synthesized and characterized. The specific pore volume and the specific surface area of the carbon nanocage materials are much higher as compared to CMK-3 mesoporous carbon. Adsorption of amino acid (histidine), flavonoid (catechin), vitamin (vitamin E, α-tocopherol), endocrine disrupter (nonylphenol), and enzyme (lysozyme) over the carbon nanocage materials was also studied. Interestingly, carbon nanocage materials showed an unusual adsorption capacity of catechin in aqueous solution. The CKT carbon nanocage materials also exhibited higher adsorption capabilities of other biomolecules used in this study as compared with the CMK-3 mesoporous carbon.     

Carbon nanocage: a large-pore cage-type mesoporous carbon material as an adsorbent for biomolecules

Novel large pore cage type mesoporous carbons, carbon nanocages, abbreviated as CKT (carbon from KIT-5) using three dimensional large cage type face centered cubic Fm3m mesoporous silica materials (KIT-5) as inorganic templates prepared at different temperature were synthesized and characterized. The specific pore volume and the specific surface area of the carbon nanocage materials are much higher as compared to CMK-3 mesoporous carbon. Adsorption of amino acid (histidine), flavonoid (catechin), vitamin (vitamin E, α-tocopherol), endocrine disrupter (nonylphenol), and enzyme (lysozyme) over the carbon nanocage materials was also studied. Interestingly, carbon nanocage materials showed an unusual adsorption capacity of catechin in aqueous solution. The CKT carbon nanocage materials also exhibited higher adsorption capabilities of other biomolecules used in this study as compared with the CMK-3 mesoporous carbon.     

Avoiding structure degradation during activation of ordered mesoporous carbons

Hierarchical micro–mesoporous carbons with high porosity development and ordered structure were prepared. The innovative proposal consists in developing microporosity in ordered mesoporous carbon by chemical activation in template presence in order to minimize the structural damage. Thus, we have directly carried out the chemical activation of a mesoporous carbon/silica composite with KOH. The effect on mesoporous ordered structure of both KOH/carbon ratio and activation temperature has been studied. Following chemical activation the specific surface area is increased from 341 to 1757 m²/g and the micropore volume becomes almost six times larger than initial value. Although a slight widening of the mesopore distribution and an increase in the mesopore volume has been observed during activation, TEM and XRD results reveal an excellent conservation of the ordered mesoporous structure during activation even at conditions well above the limits that a CMK-3 type carbon can resist.     

Preparation of nitrogen-doped mesoporous carbon nanopipes for the electrochemical double layer capacitor

The direct functionalization of ordered mesoporous carbon nanopipes was achieved by using nitrogen-containing carbon precursor and SBA-15 as a removable template. The prepared carbon material has uniform pore structure as CMK-5 type and retained a relatively large amount of nitrogen species after pyrolysis and removal of the silica template. The results of cyclic voltammetric measurement showed the prepared nitrogen-functionalized carbon materials was more stable and desirable than CMK-5 for the electrochemical capacitor.     

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。     

Adsorption of l-histidine over mesoporous carbon molecular sieves

Mesoporous carbon, CMK-3, was prepared by large pore hexagonal mesoporous silica SBA-15. The structural order and textural properties of all the materials were studied by XRD, HRTEM, and nitrogen adsorption. Adsorption of l-histidine (His) over various porous adsorbents such as CMK-3, SBA-15, and activated carbon was studied from solutions with different pH. His adsorption was observed to be pH dependent with maximum adsorption near the isoelectric point of the amino acid. CMK-3 showed a larger amount of His adsorption as compared to SBA-15 and the conventional adsorbent, namely activated carbon. CMK-3 registers the total adsorption capacity of ca. 1350 μmol g⁻¹ which is ca. 12 times higher than the adsorption capacity of SBA-15. This large difference could be mainly due to the stronger hydrophobic interaction between the non-polar side chains of amino acids and the hydrophobic surface of the mesoporous carbon as compared to mesoporous silica. The influence of ionic strengths on the adsorption of His was also studied and the results are discussed. Nitrogen adsorption of CMK-3 after His adsorption confirmed that His molecules are tightly packed inside the mesopores.     

Physical and electrochemical characterization of hydrous ruthenium oxide/ordered mesoporous carbon composites as supercapacitor

Ruthenium oxide/ordered mesoporous carbon composites materials were prepared by impregnating an ordered mesoporous carbon CMK-3 with RuCl₃ · xH₂O solution followed by annealing in nitrogen atmosphere from 80 to 400 °C. The content of ruthenium oxide in the composites ranged from 10.0 to 30.7 wt.%. X-ray diffraction (XRD), thermogravimetric analysis (TGA), nitrogen adsorption measurement and transmission electron microscopy (TEM) were used to characterize the composites. The results showed that the ruthenium oxide deposited on CMK-3 mesoporous carbon was hydrous and amorphous when annealed up to 400 °C. The specific capacitance of the composites was determined by cyclic voltammetry. Such composites had high specific capacitance, which was derived from the high specific surface area of CMK-3 mesoporous carbon and the pseudo-capacitance of amorphous RuO₂. In addition, the specific capacitance depended on the annealing temperature and the RuO₂ content. As the temperature increased, the specific capacitance decreased. In contrast, the specific capacitance increased with higher RuO₂ content and reached 633 F/g with a heavy content. However, as the RuO₂ content increased, its contribution to the pseudo-capacitance became poorer. The rate capability of the composite electrodes also decreased as a function of RuO₂ content, due to an increase in the equivalent series resistance (ESR) and the overall capacitance.     

介孔二氧化硅KIT-6介观单晶微球的合成

以非离子表面活性剂［聚环氧乙烷（PEO）-聚环氧丙烷（PPO）-聚环氧乙烷三嵌段共聚物,P123］和阳离子聚电解质（聚二甲基二烯丙基氯化铵,PAC）形成的复合物胶束为模板,合成了具有球形形貌的介孔二氧化硅KIT-6介观单晶微球。通过扫描电镜（SEM）、透射电镜（TEM）、X射线衍射（XRD）、氮气物理吸附和热重分析（TGA）等手段对合成材料的形貌及孔结构进行了表征分析。结果表明,以有机复合物胶束为模板合成出的介孔KIT-6二氧化硅材料具有较规整的球形形貌,颗粒直径为2~3 μm,具有较大的比表面积和孔体积（747 m²/g和1.3 cm³/g）,介孔孔径为8.5 nm,且在整个颗粒内部介孔保持高度的有序排列。由于长链聚电解质PAC与硅源有着较强相互作用,样品可以在较高水热温度下（160 ℃）合成,有利于提升介观结构的稳定性。该合成方法对于介孔二氧化硅KIT-6单晶微球的合成及其在催化及吸附分离等领域的应用具有一定的启发意义。     

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.     

Impact of framework structure of ordered mesoporous carbons on the performance of supported Pt catalysts for oxygen reduction reaction

Ordered mesoporous carbons (OMCs) are investigated as support materials for Pt catalysts for oxygen reduction reaction (ORR). Three types of OMCs (CMK-3, CMK-3G, and CMK-5) are prepared by a nanocasting method using ordered mesoporous silica, SBA-15, as a template. These OMCs with the same hexagonal mesostructure have different carbon frameworks and graphiticity, which can affect their surface area and microporosity. Pt nanoparticles with an average size of 1 nm are uniformly supported on the three OMCs and Ketjenblack® and their electrochemical performance and durability are evaluated. Pt/CMK-3G exhibits the highest electrochemically active surface area, kinetic current density, mass activity, and half-wave potential, whereas Pt/CMK-3 shows the lowest values. Pt/CMK-3G also shows the highest ORR activity after an accelerated durability test, with a minimal shift in half-wave potential. The higher ORR activity of Pt/CMK-3G is attributed to the formation of highly crystalline Pt particles as well as its highly graphitic, crystalline carbon structure, which causes the weak adsorption of surface oxide and a strong interaction between the Pt particles and the support. Moreover, we can establish that the mass activity of the catalysts is nearly inversely proportional to the micropore volume of the carbon supports.     

Calculation of XRD patterns of simulated FDU-15, CMK-5, and CMK-3 carbon structures

XRD patterns of model structures of the ordered mesoporous carbon materials FDU-15, CMK-5, and CMK-3 have been calculated. The structure models had been derived by filling tubular (CMK-5), rod-like (CMK-3), or channel wall (FDU-15) spaces in a given unit cell with carbon atoms. The generated carbon sites then have been used for the calculation of the XRD patterns. It could be shown that XRD patterns of CMK-5 materials vary substantially with variation of the tube diameter and carbon wall thickness. For a certain range of tube diameters, the XRD patterns do not resemble those of CMK-3 or FDU-15. The carbon material FDU-15 is isostructural to the silica SBA-15, CMK-3 is the negative replica of SBA-15. XRD patterns of CMK-3 and FDU-15 models also vary with varying rod or pore diameter but the changes are not as significant as for different CMK-5 models. As expected, the XRD patterns of FDU-15 and CMK-3 resemble each other very much for a given lattice parameter if the rods of CMK-3 are of the same size as the pore diameters of FDU-15.     

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.     

制备工艺对蔗糖基碳分子筛结构的影响

以蔗糖为碳源,F127为表面活性剂,采用K₂CO₃活化合成蔗糖碳前体,在氮气保护下炭化制备碳分子筛。通过SEM、FTIR和N₂-吸/脱附手段对碳分子筛样品进行表征,优化样品制备工艺过程。结果表明,在炭化温度为800℃下,活化剂K₂CO₃浓度为0.5mol/L,F127/蔗糖质比1：3,反应温度45℃,反应时间12h制备的碳分子筛表面孔结构显著,孔隙发达,比表面积高达1366.4423m²/g,孔容为0.865796cm³/g,孔径集中在0.64nm。     

Effect of Counterions on Synthesis of Mesoporous Silica by the Route of Template

Mesoporous silica materials with ordered hexagonal and parallel-arranged pore channel have been synthesized using cetyl trimethylammonium bromide as a template and Na₂SO₄ as counterions. Their ordered mesostructures were characterized by infrared spectroscopy, X-ray diffraction patterns, scanning electron microscopy, transmission electron microscopy, and nitrogen sorption analysis. The effects of Na₂SO₄ concentration on variations of morphology, specific surface area, and pore size were discussed; the results show that a high concentration of Na₂SO₄ induces the formation of crystal threads with a "tubules-within-tubule" structure, and also leads to mesoporous silica materials with spherical, fabaceous, sheet-like, or prismatic shapes. The results also show that a high concentration of Na₂SO₄ can make the pore size decrease, but cannot change pore wall thickness, demonstrating the stability of the hexagonal-shaped pores.     

溶胶-凝胶法制备中孔炭材料及其表征

以正硅酸乙酯为无机模板硅源，蔗糖为炭前驱物，采用溶胶-凝胶法制得了比表面积达1073．36m^2／g，孔径分布集中，平均孔径为2．75nm的中孔炭材料，并采用FT—IR、N2吸附、TG—DTA和XRD等分析手段对其进行了表征。     

Highly Ordered N-Containing Mesoporous Silica from Carbothermal Reduction–Nitridation with the Nanocasting Procedure

Highly ordered N-containing mesoporous silica materials with high specific surface area were prepared by heat treatment of the as-synthesized mesoporous silica nanocasted with carbon in its channels in flowing N₂ at high temperatures. This is the first time N₂-assisted carbothermal reduction–nitridation with nanocasting procedure has been used to prepare ordered mesoporous materials.