Ag+/Ag/ZnO多孔纳米结构纤维材料的制备及可见光催化性能

借助棉花纤维模板, 采用两步法制备了Ag⁺/Ag/ZnO多孔纳米结构纤维材料, 并利用X射线衍射(XRD)、 X射线光电子能谱(XPS)、 扫描电子显微镜(SEM)和紫外-可见光谱(UV-Vis)等对其进行了表征. 以亚甲基蓝(MB)的脱色降解为模型反应, 考察了银修饰量(摩尔分数, 0~1.50%)对ZnO纳米结构纤维材料光催化性能的影响. 结果表明, 利用模板辅助的两步法制备了Ag⁺-Ag共修饰的ZnO多孔纳米结构纤维材料Ag⁺/Ag/ZnO, Ag⁺和Ag通过改变ZnO的晶胞结构、 光吸收特性及形貌等影响其光催化性能; 在可见光条件下, Ag⁺/Ag/ZnO的催化性能优于纯ZnO, 且与修饰量有关.     

负载氯的分级多孔炭制备及其脱汞性能的研究

以纳米碳酸钙为模板,水稻秸秆为碳前驱体,采用共热解法制备了负载氯的分级多孔生物质炭。在模拟烟气条件下,利用固定床实验台架研究了生物质碳材料对烟气中的单质汞（Hg⁰）的脱除性能。采用扫描电镜（SEM）、透射电镜（TEM）、N₂吸附-脱附（BET）、程序升温脱附（Hg-TPD）以及X射线光电子能谱（XPS）等方法对材料进行表征。结果表明,盐酸浸渍不仅可去除模板产物生成多孔结构,并且有效地将氯负载到材料表面。负载氯的分级多孔炭B1C1-Cl2的比表面积和总孔容分别达到398.1 m²/g和0.4923 cm³/g。在120℃,空速（GHSV）为225000 h^-1时,脱汞效率可达95%。多孔结构有利于气体扩散,高比表面积为材料提供了更多的反应位点,微孔-介孔内表面上的C-Cl共价键为脱汞的主要化学吸附活性位点。     

新型芳香三嗪超交联多孔聚合物去除水溶液中甲基橙

Organic dyes, especially the harmful cationic dye methyl orange (MO), are emerging pollutants. The development of new materials for their efficient adsorption and removal is thus of great significance. Porous organic polymers (POPs) such as hyper-cross-linked polymers, covalent organic frameworks, conjugated microporous polymers, and polymers with intrinsic microporosity are a new class of materials constructed from organic molecular building blocks. To design POPs both with good porosity and task-specific functionalization is still a critical challenge. In this study, we have demonstrated a simple one-step method for the synthesis of the hyper-cross-linked aromatic triazine porous polymer (HAPP) via the Friedel-Crafts reaction. The resultant porous polymer was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, elemental analysis (EA), thermo-gravimetric analysis (TGA), solid-state ¹³C nuclear magnetic resonance (¹³C NMR), and nitrogen adsorption-desorption isotherms. The results show that HAPP is a rough, irregular morphology, porous organic polymer that is amorphous in nature. The novel polymer showed high Brunauer-Emmett-Teller surface area (of up to 104.36 m²∙g⁻¹), porosity, and physicochemical stability. Owing to the presence of N heteroatom pore surfaces in the network, the material exhibited a maximum adsorption capacity of 249.3 mg∙g⁻¹ for MO from aqueous solutions at room temperature. This is higher than that of some reported porous materials under the same conditions. To explain this phenomenon more clearly, theoretical quantum calculations were performed via the DFT method using Gaussian 09 software and Multiwfn version 3.4.1. It is performed to analyze the properties and electrostatic potential (ESP) of the HAPP monomer and MO. The results indicated that the N heteroatom of HAPP can easily develop strong interactions with MO, supporting the efficient adsorption of MO. The parameters studied include the physical and chemical properties of adsorption, pH, contact time, and initial concentrations. The percentage of MO removal increased as the pH was increased from 2 to 4. The optimum pH required for maximum adsorption was found to be 5.6. Adsorption kinetics data were modeled using the pseudo-first-order and pseudo-second-order models. The results indicate that the second-order model best describes the kinetic adsorption data. The adsorption isotherms revealed a good fit with the Langmuir model. More importantly, the HAPP can be regenerated effectively and recycled at least five times without significant loss of adsorption capacity. Therefore, it is believed that HAPPs with hierarchical porous structures, high surface areas, and physicochemical stability are promising candidates for the purification and treatment of dyes in solution.     

蒙脱土表面键合配位体固相萃取填料的制备及其对重金属离子的吸附性能

通过酸洗、硅烷偶联剂表面活化、键合苯甲酰异硫氰酸酯对蒙脱土进行改性,制得新型固相萃取(SPE)材料。 采用红外光谱、扫描电子显微镜、X射线光电子能谱表征了改性蒙脱土的结构和形貌。 考察了制备的SPE填料对水中As³⁺、Bi³⁺、Cu²⁺、Sb³⁺、Sn²⁺和Pb²⁺的吸附性能,确定了最佳固相萃取条件,对6种金属离子吸附容量分别为10.83、11.92、12.67、10.43、10.01及10.54 mg/g。 通过SPE与电感耦合等离子体质谱联用测定了样品中As³⁺、Bi³⁺、Cu²⁺、Sb³⁺、Sn²⁺和Pb²⁺ 6种重金属离子的含量,检出限分别为0.024、0.013、0.075、0.037、0.011和0.064 μg/L。     

Fabrication and Adsorption Properties of Hybrid Material with Micropores from SBA-15

A novel hybrid material with microporous structure was fabricated from SBA-15 with mesopores via silane modification and hydrolysis. Two kinds of pores with diameters of 6.5 and 1.9 nm were found in the hybrid material. Compared to that of SBA-15, the surface area of the hybrid material increased from 395.9 m²/g to 667.4 m²/g while its porous volume decreased. The new hybrid material was found to have high efficiency in removing NaCl from solution, and the maximum adsorption capacity of it was ca. 517.5 mg/g.     

热剥离法制备石墨烯纳米片对Pb2+和Cd2+的吸附

石墨粉氧化后,在氮气气氛下,快速高温剥离制得石墨烯纳米片。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(HRTEM)、拉曼(Raman)光谱、傅里叶变换红外(FT-IR)光谱和氮气吸附-脱附等分析手段对石墨烯样品进行了表征。这些分析测试结果显示:石墨烯样品主要由很薄的1-4层石墨组成,呈褶皱状态,比表面积为628.5 m²·g^-1。研究了石墨烯吸附水溶液中的Pb²⁺和Cd²⁺的pH值、吸附时间、吸附温度和金属离子初始浓度等影响因素, Pb²⁺和Cd²⁺的最大吸附量分别为460.20和72.39 mg·g^-1。结果表明,热剥离法制得的高质量石墨烯纳米片可以作为一种高效的从水中去除Pb²⁺和Cd²⁺的吸附材料。     

双金属磷化物和杂原子共修饰碳材料的制备及电催化性能

以高含氮量的苯胺五聚体二羧酸为配体,在预氧化的泡沫镍上通过溶剂热反应合成了Fe,Co金属有机框架材料Fe/Co-MOF,再以Fe/Co-MOF为金属源和碳源,经磷化后制备出一种新型的双金属(Fe,Co)和杂原子(N,P)共掺杂的碳材料Fe/Co/P-NPs.通过扫描电子显微镜和高分辨透射电子显微镜表征发现,Fe/Co/P-NPs由纳米粒子和纳米片组成,并且形成Fe₂P和Co₂P两种晶体.电化学测试结果表明,Fe/Co/P-NPs在析氢、析氧及水电解中表现出了优异的多功能催化活性.在1 mol/L KOH中,Fe/Co/P-NPs在10和100m A/cm²电流密度时的析氧过电位分别为270和300 m V,均小于其它对比材料,优于负载在泡沫镍上的RuO₂.作为水电解双功能催化剂,Fe/Co/P-NPs仅需1. 48 V的电位即可获得10 m A/cm²的电流密度.     

基于MCM-41分子筛表面的镱离子印迹聚合物的制备及其性能

运用离子印迹技术,以3-氯丙基三乙氧基硅烷为锚定剂,将功能单体直链聚乙烯亚胺(PEI)接枝在MCM-41分子筛表面,选择镱离子作为模板离子,以环氧氯丙烷交联制备出基于MCM-41表面的镱离子印迹聚合物Yb(Ⅲ)-IIP-PEI/MCM-41,并以同样的方法制备非离子印迹聚合物(NIP-PEI/MCM-41)。 利用傅里叶变换红外光谱仪和扫描电子显微镜等技术手段对Yb³⁺印迹聚合物进行表征,采用静态吸附法确定了Yb(Ⅲ)-IIP-PEI/MCM-41对Yb³⁺的最佳吸附条件及选择性吸附性能。 结果表明,Yb(Ⅲ)-IIP-PEI/MCM-41和NIP-PEI/MCM-41的最大吸附量分别为229.93和99.27 mg/g;印迹材料对Yb³⁺的吸附符合Langmuir模型;吸附平衡在40 min的时候基本可以达到,可以利用准二级动力学模型来描述其吸附过程;Yb(Ⅲ)-IIP-PEI/MCM-41对Yb³⁺具有较强的选择性,同时也具有很好的重复使用性能。 成功地将MCM-41和离子印迹聚合物的优点结合起来,制备出一种对稀土Yb离子既有高吸附量又有高选择性的吸附材料,为进一步将其应用在处理实际废水,分离回收低浓度稀土废水中的稀土元素等方面打下了基础。     

超声辅助的硅中心多孔芳香材料的合成与表征

以四(4-溴苯基)硅烷为基元, 利用超声辅助的Yamamoto 偶联反应, 合成了硅中心的多孔芳香材料(Si-PAF). 通过调节超声参数, 优化了反应条件. 采用红外光谱、 元素分析、 扫描电子显微镜和透射电子显微镜等手段表征了Si-PAF的结构及形貌, 利用氮气吸附实验考察了其孔道结构.     

低温甲烷氧化偶联纳米SrTi_(0.975)Li_(0.025)O_(3-δ)催化剂的原位ESR和TPSR表征

采用溶胶-凝胶法制备纳米钙钛矿型复合氧化物催化剂SrTi1-xLixO3-δ(x=0、0.025、0.050),用微型催化反应评价装置结合XRD、TEM、原位ESR和程序升温表面反应(TPSR)等方法,研究甲烷氧化偶联(OCM)纳米SrTi1-xLixO3-δ催化剂结构和催化性能。结果表明,B位掺杂适量的低价Li+离子可优化纳米SrTiO3催化剂低温(~650℃)甲烷氧化偶联催化性能,Li+掺杂量为0.025时获得最高的甲烷转化率和C2选择性。与柠檬酸法制相同组成的常规催化剂相比,SrTi0.975Li0.025O3-δ纳米催化剂具有较优良的低温OCM催化性能和相同温度下更高的C2选择性。SrTi0.975Li0.025O3-δ纳米催化剂优良的催化性能与其表面原子配位不饱和存在F中心相关。     

Adsorption of CO2 and H2 on Nitrogen-doped Porous Carbon from Ionic Liquid Precursor

Nitrogen-doped mesoporous carbon material was prepared via a simple one-step thermolysis method via the carbonization of ionic liquid, 1-cyanomethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([MCNIm]⁺[Nf₂T]^-). The nanostructure of the resultant carbon material was characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM) and the types of N-containing groups of the carbon material were investigated by X-ray photoelectron spectroscopy(XPS). The N-content of the carbon material is 18.6%(mass fraction) based on the elemental analysis. The produced mesoporous carbon material was further used as the solid sorbent for H₂ and CO₂. The hydrogen uptake capacity and H₂ isosteric heat of the carbon material were discussed. Furthermore, the nitrogen-containing carbon material as good sorbent shows relatively high adsorption and separation ability for CO₂ from CH₄, for which the heat of CO₂ adsorption(Q_st) is 31.8 kJ/mol. The mesoporous structure and nitrogen functionality make the carbon material with high adsorption capacity and selectivity for CO₂ and ability to store H₂, indicating that this kind of nitrogen-doped carbon material originated from ionic liquids is a promising sorbent material for high-performance separation and adsorption.     

基于钛锡载体的SCR低温脱硝催化剂的表面性质研究

采用共沉淀法制备TiO₂-SnO₂固溶体,浸渍法负载CeO₂得到一系列xCeO₂/TiO₂-SnO₂负载型催化剂,在模拟NH₃选择性催化还原NO_x(NH₃-SCR)反应条件下考察催化剂低温脱硝活性。通过X射线衍射(XRD)、比表面积测定(BET)、程序升温还原(H₂-TPR)、程序升温脱附(NH₃-TPD)、高分辨率透射电子显微镜(HRTEM)、原位漫反射傅里叶变换红外光谱(in situ DRIFTS)等表征技术,研究了氧化铈负载后催化剂的微观结构、表面物种的存在状态、表面酸位等表面性质及NH₃吸附特性。结果表明,Ce:Ti物质的量比为0.1时,催化剂催化脱硝反应活性最高,同时具有较宽的温度窗口(250~300℃)和热稳定性;铈的过量负载会导致催化剂比表面积减小、活性窗口变窄,同时其氧化还原能力和NH₃吸附能力也减弱。NH₃-TPD结果显示,CeO₂的负载导致催化剂NH₃在弱酸及中等酸位的吸附显著增强,与催化剂NH₃-SCR最佳反应物温度降低有关。in situ DRIFTS表明,xCeO₂/TiO₂-SnO₂催化剂的Lewis酸位和Brønsted酸位强度均明显增强,同时,在1657~1666cm^-1处出现新的Brønsted酸位,参与SCR反应的主要物质是NH₄⁺分子。     

氮硫双掺杂活性炭材料的制备和电容性能

以头发和蔗糖为原料, 通过水热碳化和KOH活化两步法制备了氮硫双掺杂微孔炭材料. 利用扫描电子显微镜, 透射电子显微镜, 氮气吸脱附, X射线光电子能谱, 电子能谱和傅里叶交换红外光谱等手段系统表征了所制备活性炭材料的微观形貌, 孔隙结构和表面化学性质. 并在6 mol·L^-1 KOH溶液中研究了所制备活性炭材料的电容性能. 氮气吸脱附测试表明, 所制备活性炭材料的比表面积最高可达1849.4 m²·g^-1, 孔道以微孔为主. 所制备活性炭材料氮元素含量为1.6%-2.5% (原子分数(x))), 硫元素含量为0.2%-0.5% (x). 由于N、O、S官能团的协同作用, 所制备碳材料表现出明显的赝电容. 活性炭材料的比电容值最高可达200 F·g^-1, 对应的能量密度为6.9 Wh·kg^-1. 功率密度达到10000 W·kg^-1时, 能量密度仍达到4.1 Wh·kg^-1. 本文的工作表明以生物质为原料可以方便制备氮硫双掺杂活性炭电极材料.     

Pd/PdO纳米复合微球的合成及催化性能

采用甲基丙烯酸锌加速还原氯化钯(PdCl₂) 溶液中的钯离子(Pd ²⁺)为钯(Pd) 纳米微球, 进而用得到的钯纳米微球直接制备钯/氧化钯(Pd/PdO) 纳米复合微球. 通过扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 粉末X射线衍射分析(XRD)及X射线光电子能谱分析(XPS) 等方法对 Pd/PdO 纳米复合微球进行表征, 结果表明, 制备的纳米复合微球为表面粗糙、 大小均一的纳米微球. 采用紫外-可见吸收光谱(UV-Vis) 等方法考察了 Pd/PdO 纳米复合微球在对硝基苯酚(4-NTP) 还原反应中的催化性能, 发现其具有良好的催化活性和循环稳定性.     

Cu-incorporated mesoporous materials: Synthesis, characterization and catalytic activity in phenol hydroxylation

A series of novel Cu-incorporated mesoporous materials (CMMs) with molar ratios of Cu/Si ranging from 1/200 to 1/20 were synthesized by sol–gel method using glutaric acid as template. The materials were characterized by powder X-ray diffraction (XRD), N₂ adsorption, diffuse reflectance UV–vis spectroscopy and transmission electron microscopy (TEM). The results indicate that the CMMs have a three-dimensional (3D) worm-like mesoporous structure with a surface area between 600 and 800 m² g⁻¹ and the copper ions are incorporated into the matrix with octahedral environment. The catalytic activity of these CMMs in the phenol hydroxylation using H₂O₂ as oxidant is comparable to that of TS-1. Effects of Cu/Si molar ratio in the catalyst and the influence of various reaction parameters on the catalytic activity were investigated in detail and the optimized reaction condition was acquired.     

催化剂表面Cu0含量对二氧化碳加氢合成C2+醇性能的影响

通过在空气气氛下焙烧Cu@Fe-MIL-88B MOF材料制备了CuFe组分均匀分散的催化剂前驱物, 该前驱物经过不同温度下的预还原制得表面具有不同Cu和Fe价态分布的系列催化剂. 将所制备的催化剂用于固定床反应器上CO₂加氢合成C₂₊醇的性能研究, 并结合催化剂的X射线衍射(XRD)、 X射线光电子能谱(XPS)、 氢气程序升温还原(H₂-TPR)、 氮气吸附-脱附、 扫描电子显微镜(SEM) 和高分辨率透射电子显微镜(HRTEM)等表征结果发现, 较高的还原温度增加了催化剂表面低价态的Cu和Fe的含量; 当还原温度为350 ℃时, 催化剂表面Cu⁰/(Cu⁺+Cu⁰)摩尔比为73.9%, 单质Fe摩尔分数为0.40%, 催化效果最好, CO₂转化率达到6.82%, 总醇选择性为39.4%, 其中C₂₊醇的摩尔比达到95.1%.     

新型Brnsted-Lewis酸性催化剂LaPW_(12)O_(40)/SiO_2制备及其在催化酯化反应合成生物柴油中的应用

以十二磷钨杂多酸(Tungstophosphoric acid,H_3PW_(12)O_(40))为基体,分别通过普通浸渍法、溶胶凝胶法和超声浸渍法进行了La3+改性作用,合成了三种固体酸催化剂A-LaPW_(12)O_(40)、B-LaPW_(12)O_(40)/Si O2和C-LaPW_(12)O_(40)。采用X射线荧光光谱(XRF)、孔径比表面积测定、X射线粉末衍射(XRD)、透射电镜(TEM)、红外光谱(FT-IR)、热重(TG)、N2吸附-脱附、NH3程序升温脱附(NH3-TPD)、吡啶吸附红外光谱(Py-FTIR)、X射线光电子能谱(XPS)等方法对合成的催化剂进行了表征,并比较了以上催化剂在用于催化以油酸和甲醇为反应物经酯化反应合成生物柴油时的活性和稳定性。结果表明,B-LaPW_(12)O_(40)/Si O2具有最高催化活性,当甲醇与油酸的物质的量比为8∶1,催化剂用量为反应物总质量的2%,反应温度为65℃,反应1 h后,油酸的转化率即高达93%。循环使用B-LaPW_(12)O_(40)/Si O2催化剂六次后,油酸的转化率仍高达86.4%。B-LaPW_(12)O_(40)/Si O2的高催化活性和稳定性可归因于在溶胶凝胶的转化过程中,作为硅源材料的四乙氧基硅(TEOS)易在酸性条件下发生水解反应形成Si O2网络,进而Si O2网络中的硅醇键与H_3PW_(12)O_(40)中的H+发生配位作用,生成具有强静电吸附力的(≡Si-OH2+)(H2PW12O-40)络合物。随着该络合物的形成,促进了La3+在Si O2表面的吸附而堵塞了H_3PW_(12)O_(40)的孔道结构,抑制了H_3PW_(12)O_(40)颗粒在焙烧过程中进一步聚集长大。Si O2将作为载体并以干凝胶状态存在于B-LaPW_(12)O_(40)/Si O2催化剂中,由于Si O2凝胶的高比表面积而使B-LaPW_(12)O_(40)/Si O2具有了较大的比表面积,从H_3PW_(12)O_(40)的1.4 m2/g增加至31.3 m2/g。并且,通过吡啶吸附红外光谱确定B-LaPW_(12)O_(40)/Si O2为Br9nsted-Lewis酸型固体酸,由于Br9nsted酸位易与酯化反应过程中生成的水发生水合反应而失活,因而Lewis酸位的形成有助于减少催化剂的失活现象发生。Lewis酸位的出现可归因于(≡Si-OH2+)(H2PW12O-40)与吸附在其表面的具有强吸电子作用的La3+发生键合作用后生成了LaPW_(12)O_(40)/Si O2。     

Multiwalled Carbon Nanotubes Modified with Silylated-salicylaldimine Co(II) and Pd(II) Complexes as Precatalysts in Ethylene Oligomerization

MWCNTs-Co(II) and Pd(II) were prepared through grafting silylated-salicylaldimine Pd(II) and Co(II) on multiwalled carbon nanotubes(MWCNTs) for ethylene oligomerization. The structures of the two MWCNTs-supported catalysts were characterized by means of scanning electron microscopy(SEM), X-ray diffraction(XRD), Fourier transform infrared(FTIR) spectroscopy, thermogravimetric analyses(TGA) and nitrogen adsorption and desorption. And the influence of the supported pattern on the catalytic properties for ethylene oligomerization was investigated. The results revealed that the silylated-salicylaldimine complexes were grafted on the inner and outer surfaces of the carbon nanotubes and the pore size and BET surface area of MWCNTs decreased. Compared with the homogeneous catalysts, the two MWCNTs-supported catalysts had higher selectivity for hexene and 1-hexene in the presence of diethylaluminum chloride(DEAC) with a small molecule size due to confinement effect. MWCNTs-Pd exhi-bited higher activity and higher selectivity for C₈⁺ olefin compared to MWCNTs-Co due to electronic factors. The catalytic activities of MWCNTs-Pd and MWCNTs-Co decreased from 24.18×10⁵g·(mol Pd·h)^–1 and 20.57×10⁵g·(mol Co·h)^–1 to 19.79×10⁵g·(mol Pd·h)^–1 and 13.14×10⁵g·(mol Co·h)^–1 after the third recycle reaction, respectively.     

Synthesis of Monoclinic Li_(0.33)MnO_2 and Its Electrochemical Properties in Different Potential Windows

Li0.33MnO2 cathode material was synthesized by solid state reaction. The material showed a small coherent domain size about 10 nm determined by X-ray diffraction and transmission electron microscopy. The electrochemical properties of the material were studied in different potential windows of 3.5―2.0 V and 4.3―2.0 V. An irreversible transformation to spinel phase was observed in the initial several cycles, which was more prominent on cycling at 4.3―2.0 V. Electrochemical impedance spectroscopy showed that the Li+ diffusion coefficient of the material was about 2×10–9 cm2/s. Li0.33MnO2 showed a reversible discharge capacity of 140 and 200 mA·h/g in the potential windows of 3.5―2.0 V and 4.3―2.0 V, respectively. But the capacity retention at 4.3―2.0 V was poor due to the thicker spinel layer formed on the material surface.     

Towards High-performance Lithium-Sulfur Batteries: the Modification of Polypropylene Separator by 3D Porous Carbon Structure Embedded with Fe3C/Fe Nanoparticles

Lithium-sulfur(Li-S) batteries with high energy densities have received increasing attention. However, the electrochemical performance of Li-S batteries is still far from the satisfactory of the practical application, which can be mainly attributed to the shuttling of polysulfides and the slow reaction kinetics of polysulfide conversion. To address this issue, a 3D porous carbon structure constructed by 2D N-doped graphene and 1D carbon nanotubes with embedded Fe₃C/Fe nanoparticles(NG@Fe₃C/Fe) was designed and prepared by a simple programmed calcination method for the modification of polypropylene(PP) separator. The Fe₃C/Fe nanoparticles demonstrate an excellent catalytic conversion and strong chemisorption towards polysulfides, while the unique architecture of N-doped graphene promotes the Li⁺/electron transfer and the physical adsorption of polysulfides. The electrochemical performance of the Li-S batteries with the NG@Fe₃C/Fe-modified separator is significantly improved. A large discharge capacity of 1481 mA∙h∙g^-1 is achieved at 0.2 C(1 C=1675 mA/g), and a high capacity of 601 mA∙h∙g^-1 is maintained after discharged/charged for 500 cycles at a current rate of 1 C. This work provides a new approach for the development of high-performance Li-S batteries through the modification of the PP separator by rationally designed composites with large adsorption capability to polysulfides, good wettability to the electrolyte and high catalytic property.