金属有机骨架及其复合材料基于筛分复合效应的C2分离的研究进展

精细化分离是石油化工生产的关键技术及研究热点之一,其中C2 (C2H2/C2H4和C2H4/C2H6)的高效精细分离更是现代化工过程中高质量生产的难点和新挑战.传统的热驱动分离过程(如精馏分离和选择性催化加氢分离)存在能耗高、经济效益低的缺陷,而采用非热驱动分离过程(如吸附分离和膜分离)可大幅度节能降耗.在众多吸附分离...     

UTSA-280的氨改性以及C2H4/C2H6分离性能研究

炼厂干气中回收乙烯是扩宽C₂H₄来源的有效途径,但C₂H₄和C₂H₆物理性质和分子尺寸非常接近,分离困难.金属有机骨架材料(MOFs)近年来在低碳烃分离领域展现出广阔的前景.本工作采用氨吸附改性调节UTSA-280的结构,通过一维直孔道大小的调节实现C₂H₄/C₂H₆的高效分离.改性后的UTSA-280具有独特的超微孔结构能提升C₂H₄的吸附,而完全不吸附稍大的C₂H₆,实现理想的C₂H₄/C₂H₆吸附选择性(>1000).结果表明,改性后的UTSA-280的C₂H₄吸附量可提高至2.83 mmol/g,与未改性的材料相比增加29%,并且能阻挡C<...     

机器学习与分子模拟协同的CH4/H2分离金属有机框架高通量计算筛选

在减少CO₂排放、实现碳中和的背景下, 金属有机框架(MOFs)在清洁能源领域展现出广阔应用前景. 提出一种机器学习和分子模拟协同的分层筛选策略, 快速、准确地从134185个假设MOFs中识别出具有最佳CH₄/H₂分离性能的吸附剂. 首先, 根据MOFs的结构性质, 筛掉孔径或体积比表面积不恰当的吸附剂, 初筛后MOFs的数量减至62278个. 接下来, 抽取10% MOFs将结构和化学混合描述符作为特征, 利用随机森林分别构建变压吸附和真空变压吸附过程中其对CH₄的吸附剂性能得分(APS)预测模型. 相比于其他模型构建策略, 基于本策略构建的模型具有最优预测准确性, 可用于余下MOFs的性能预测. 随后根据APS预测值排序, 筛选出Top 1000的MOFs并利用分子模拟修正预测结果, 进一步确定了10个最佳MOFs. 最后, 对描述符的重要性进行解释, 揭示了实现模型在不同操作场景下的迁移具有潜力, 为未来开发适用于多操作场景下的高性能MOFs筛选方法提供了一条高效的研究路径和方法.     

Cu改性ZIF-67衍生的Co3O4/C催化剂的CO-SCR脱硝特性

采用CO气体对NO进行选择性催化还原(CO-SCR)是一种有前景的脱硝技术.目前已报道的CO-SCR催化剂的脱硝特性主要是在无氧条件下开展的研究,考虑到实际应用情况,探究一种在有氧环境中具有较高脱硝效率的催化剂是很有必要的.作为一种新型功能性材料的金属有机骨架是脱硝催化剂的优良载体,其中ZIFs系列具有优良的性能.引入Cu对ZIF-67衍生的Co₃O₄/C进行改性,通过浸渍法在载体上负载铜后,热解氧化获得一系列CuO_x/Co₃O₄/C催化剂.利用ICP、 SEM、 XRD、 TEM、 TGA、 XPS、 BET和H₂-TPR等技术对催化剂的物理化学性质进行表征,结果表明,由于Cu的引入增加了表面的氧空位,改善了氧化还原能力,进而提高了催化剂脱硝活性.在制备的一系列催化剂中, 8.0 CuO_x/Co₃O₄/C在300℃时即可达到约95%NO转化率,并且其N₂选择性也达到9...     

MIL-101(Cr)/GO复合吸附剂的O2/N2分离性能研究

变压吸附（PSA）制取O₂的核心是吸附剂.近年来,金属有机骨架（MOFs）被认为是一种具有广阔应用前景的新型吸附剂.通过水热法制备了MIL-101（Cr）/氧化石墨烯（GO）.结果表明,MIL-101（Cr）/GO-15具有更高的比表面积（3486 m²·g^-1）和更大的孔体积（2.39 cm³·g^-1）,因此也表现出更高的O₂吸附量（0.54 mmol·g^-1）.进一步根据理想吸附溶液理论（IAST）预测了其在O₂/N₂体积比为1：4混合气体中的O₂/N₂选择性为1.2,相比MIL-101（Cr）提高了17.65%.同时,MIL-101（Cr）/GO-15的循环利用性能更佳,经过三次O₂吸脱附循环后,依然拥有高达80%的O₂吸附量,具有较好的循环再生性能.     

Kinetics of hydrogen peroxide decomposition in aqueous sulfuric acid over palladium/carbon: effcet of acid concentration

Decomposition of H₂O₂ over Pd (5%)/carbon in an aqueous sulfuric acid solution at different acid concentrations (0-10 mol/L) and temperatures (281-313 K) in a magnetically stirred glass reactor has been investigated. The catalytic activity, activation energy and frequency factor for the decomposition decrease with increasing acid concentration; the decrease in the activation energy is, however, very small. This revised version was published online in June 2006 with corrections to the Cover Date.     

The Catalytic Dehydrogenation of c2h6 to c2h4 under non-Oxidative Conditions over the 6cr/g-al2o3Catalyst

In the present paper, the catalytic dehydrogenation of C₂H₆ to C₂H₄ under non-oxidative conditions was investigated in a fixed-bed micro-reactor under ambient pressure at 823 - 923 K. The 6Cr/g-Al₂O₃ catalyst was found to be the best catalyst among the g-Al₂O₃, SiO₂, MCM41, MgO and Si-2 supported chromium oxide catalysts. The features of the 6Cr/g-Al₂O₃ catalyst for the reaction could be listed as follows: (1) At 823 - 923 K, the C₂H₄ selectivity of 92.5-78.6% at a C₂H₆ conversion of 9.5-29.8% could be obtained. (2) The catalyst had the good regeneration performance, i.e., could be regenerated by air repeatedly. (3) The main products were C₂H₄, CH₄, H₂ and coke. No carbon oxides were identified.     

铕基金属有机框架材料从混合染料中选择性分离亚甲基蓝

利用紫外-可见吸收光谱和粉末X射线衍射等技术, 通过染料吸附实验、 混合染料吸附实验、 吸附动力学实验和循环吸附实验, 研究了一种铕基金属有机框架材料从混合染料水溶液中选择性分离亚甲基蓝的性能与机理. 研究结果表明, 该材料对亚甲基蓝的最大吸附量为20 mg/g, 在12 h内可完成对亚甲基蓝的选择性吸附, 且可以循环使用3次以上. 混合染料吸附实验结果表明, 该材料的吸附选择性源于孔道的静电作用与尺寸排斥效应.     

金属有机框架催化甲烷直接转化研究进展

甲烷作为重要的气态化石能源,广泛存在于天然气中.利用非均相催化剂将甲烷转化为液体燃料是天然气全面经济开发的有效策略之一.目前催化剂普遍存在催化速率较慢、效率不高及催化剂难回收的问题.作为较新出现的晶态多孔材料,金属有机框架(MOFs)已被证明在各种功能化纳米材料的设计和合成中是有前途的非均相催化剂或载体/前体.本文系统...     

金属有机框架分离纯化C4～C6碳氢化合物的研究

C₄～C₆碳氢化合物作为重要的化工原料和能源,在传统的石化工业生产中,主要通过精馏进行分离提纯,此过程能耗高、设备费用昂贵、经济效益低.利用固体吸附剂进行吸附式分离,不仅可以降低能源成本,而且可以提高效率.金属有机框架（metal-organic frameworks,MOFs）作为一类由金属离子或团簇和有机单体组装而成的晶态多孔材料,具有高孔隙率、规整开放的孔道、丰富的官能团和多样的结构,在气体储存与分离中有着良好的应用前景.介绍了C₄～C₆碳氢化合物分离的重要性,并从MOFs分离机制出发,概述了目前MOF材料用于分离纯化C₄～C₆碳氢化合物的分离机理和研究进展,为开发新型具有良好分离性能的MOF材料提供研究思路.     

Dynamic Studies on Kinetic H2/D2 Quantum Sieving in a Narrow Pore Metal–Organic Framework Grown on a Sensor Chip

The separation of deuterium from hydrogen still remains a challenging and industrially relevant task. Compared to traditional cryogenic methods for separation, based on different boiling points of H₂ and D₂, the use of ultramicroporous materials offers a more efficient alternative method. Due to their rigid structures, permanently high porosity, tunable pore sizes and adjustable internal surface properties, metal–organic frameworks (MOFs), a class of porous materials built through the coordination between organic linkers and metal ions/clusters, are more suitable for this approach than zeolites or carbon-based materials. Herein, dynamic gas flow studies on H₂/D₂ quantum sieving in MFU-4, a metal-organic framework with ultra-narrow pores of 2.5 Å, are presented. A specially designed sensor with a very fast response based on surface acoustic waves is used. On-chip measurements of diffusion rates in the temperature range 27–207 K reveal a quantum sieving effect, with D₂ diffusing faster than H₂ below 64 K and the opposite selectivity above this temperature. The experimental results obtained are confirmed by molecular dynamic simulation regarding quantum sieving of H₂ and D₂ on MOFs for which a flexible framework approach was used for the first time.     

具有四连接网络的单一手性螺旋配位聚合物的合成与结构表征

在水热反应条件下,使用乳酸衍生物[(R)-H2CBA和(S)-H2CBA]和辅助配体1,4-DIB与Ni2+组合,制备出一对具有dia拓扑网络的单一手性框架材料[Ni2((R)-CBA)2(1,4-DIB)3(H2O)2]·x H2O(1-D)和[Ni2((S)-CBA)2(1,4-DIB)3(H2O)2]·x H2O(1-L).配合物1-D和1-L具有2种由1,4-DIB与Ni2+组构建而成的螺旋链以及二重穿插的结构特征.此外,对上述配合物进行了粉末X射线衍射、热失重和圆二色谱测试并对结果进行了分析.     

Two New Metal-organic Frameworks Constructed from 3,4,5-Substituted-1,2,4-Triazole Ligands

Two new complexes,[Zn（L1）2（SCN）2]·H2O（1,L1 = 3,5-dimethyl-4-p-tolyl-4H1,2,4-triazole and [Cd3（L2）6（SCN）6]（2,L2 = 3,5-dimethyl-4-phenyl-4H-1,2,4-triazole）,have been hydrothermally prepared and characterized by single-crystal X-ray diffraction,IR spectroscopy,elemental analysis and PXRD.Complex 1 crystallizes in monoclinic,space group P21 /n with a = 11.246（13）,b = 9.640（11）,c = 26.13（3）,β = 100.97（3）,V = 1108.5（3） 3,Z = 4,C24 H28 N8 OS2 Zn,Mr = 572.02,Dc = 1.366 g/cm3,μ = 1.065 mm-1,S = 0.992,F（000） = 1184,the final R = 0.0602 and wR = 0.1700 for 2925 observed reflections（I 2σ（I））.Complex 2 crystallizes in triclinic,space group P1 with a = 11.6669（3）,b = 12.0957（2）,c = 14.3674（3）,α = 105.380（3）,β = 91.020（2）,γ = 92.4100（10）o,V = 1952.30（7）3,Z = 1,C66H66N24S6Cd3,Mr = 1725.08,Dc = 1.467 g/cm3,μ = 1.025 mm-1,S = 1.037,F（000） = 870,the final R = 0.0336 and wR = 0.0946 for 7819 observed reflections（I 2σ（I））.In the title complexes,complex 1 is a mononuclear molecule where the centre Zn（II） coordinates to two 3,4,5-substituted 1,2,4-triazole ligands（L1） and two terminal SCN-anions in a tetrahedral environment while six-coordinated centre Cd（II） atoms with octahedral geometry in complex 2 are bridged by virtue of substituted 1,2,4-triazole（L2） in N1,N2-bridging mode and μ2-N,N-SCN-anions into a trinuclear molecule.     

二维金属-有机骨架膜的制备及其在分离中的应用

膜分离在面向能源与环境问题的分离过程中具有极大的应用前景,近几十年内发展迅速.金属-有机骨架(MOFs)是一种新型微孔材料,具有孔结构均一、可调控、多样化的特点,用其制备的MOF膜在分离领域极具应用潜力.而二维(2D)材料的飞速发展,使2D MOF膜也成为倍受关注的一类新型分离膜.由2D MOF纳米片构筑成的超薄分离膜...     

Sensing mechanism elucidation of a europium(III) metal–organic framework selective to aniline: A theoretical insight by means of multiconfigurational calculations

A theoretical procedure, via quantum chemical computations, to elucidate the detection principle of the turn-off luminescence mechanism of an Eu-based Metal-Organic Framework sensor (Eu-MOF) selective to aniline, is accomplished. The energy transfer channels that take place in the Eu-MOF, as well as understanding the luminescence quenching by aniline, were investigated using the well-known and accurate multiconfigurational ab initio methods along with sTD-DFT. Based on multireference calculations, the sensitization pathway from the ligand (antenna) to the lanthanide was assessed in detail, that is, intersystem crossing (ISC) from the S₁ to the T₁ state of the ligand, with subsequent energy transfer to the ⁵D₀ state of Eu³⁺. Finally, emission from the ⁵D₀ state to the ⁷F_J state is clearly evidenced. Otherwise, the interaction of Eu-MOF with aniline produces a mixture of the electronic states of both systems, where molecular orbitals on aniline now appear in the active space. Consequently, a stabilization of the T₁ state of the antenna is observed, blocking the energy transfer to the ⁵D₀ state of Eu³⁺, leading to a non-emissive deactivation. Finally, in this paper, it was demonstrated that the host-guest interactions, which are not taken frequently into account by previous reports, and the employment of high-level theoretical approaches are imperative to raise new concepts that explain the sensing mechanism associated to chemical sensors.     

自生长镍基MOF材料的结构调控及其电化学性能

以六水合氯化镍(NiCl2·6H2O)为金属盐,对苯二甲酸(PTA)为有机配体,通过改变溶剂的类型,采用一步溶剂热法在泡沫镍表面自生长高负载量的镍基MOF材料(Ni-MOF/NF)。溶剂对PTA的溶解性越好或pH值越高,PTA在溶液中的去质子速率越快,材料的形核速率越快。自生长镍基MOF材料在不同溶剂体系下表现出球簇、片状和块体状三类形貌,同时负载量也随之改变。当采用三元混合溶剂(N,N-二甲基甲酰胺、水和乙醇的体积比为1∶1∶1)时,Ni-MOF/NF材料在泡沫镍表面的负载量达到10 mg·cm-2,在3 mol·L-1 KOH电解液中1 mA·cm-2的电流密度下的面积容量达到8780 mF·cm-2。在5 mA·cm-2电流密度下,面积容量仍达到5544 mF·cm-2,容量保持率为63%,表现出优良的倍率性能。经过1000次充放电循环后容量保持率为56%,具有良好的循环稳定性能。