一种具有Z-Scheme机制的高效可见光驱动的介孔AgI@Fe-MIL-88B-NH_2光催化剂（英文）

以磺化聚苯乙烯微球为模板制备了具有开口结构的介孔Fe-MIL-88B-NH_2球壳,据此进一步通过原位反应法合成一种新型具有可见光活性的AgI改性Fe-MIL-88B-NH_2微球。与纯的AgI和Fe-MIL-88B-NH_2相比,制备的AgI@Fe-MIL-88B-NH_2复合材料的光催化活性显著提高,这是由于吸附能力和电荷分离均得到增强的缘故。电荷分离机制可归因于形成了不含氧化还原调节剂的直接Z-Scheme系统,该系统使光生电子从Fe-MIL-88B-NH_2的导带迁移至AgI的价带上,从而产生活性更强的·O2-和·OH。     

中空纳米二氧化硅复合微球的制备及其对蛋白的亲和分离

利用水热法合成了中空巯基纳米二氧化硅微球(SiO₂-SH), 然后在其表面修饰亚氨基二乙酸基团(-IDA), 形成了中空SiO₂-SH/IDA双功能化纳米微球。利用该纳米微球表面的-SH和-IDA双功能团, 可以更多的吸附溶液中的Ni²⁺, 形成SiO₂-SH/IDA-Ni²⁺复合微球从而可以更好的分离以六聚组氨酸为标签的(His-tagged)蛋白。结果显示制备的样品对分离His-tagged蛋白具有广谱性, 并且具有较好的再生能力。     

α-Ti(HPO4)2微球负载型催化剂的合成及其烯烃聚合催化性能

2种茂金属催化剂及1种后过渡金属催化剂分别被固载于经过甲基铝氧烷处理后的α-Ti（HPO₄）₂微球表面,制备得到3种微球负载型催化剂。在烯烃聚合反应过程中,3种负载型催化剂均表现出比硅胶负载型催化剂更高的催化活性。2种茂金属负载型催化剂在乙烯、丙烯聚合反应中的活性分别高达6.8×10⁷ g_PE·（mol_Zr·h）^-1和5.0×10⁷ g_PP·（mol_Zr·h）^-1,所产生的烯烃聚合产物分子量分布较窄（M_w/M_n<2.3）,表现出良好的单中心催化特性,而且丙烯聚合产物的等规度高达96.5%。负载型后过渡金属催化剂在乙烯聚合反应中的活性稍低,但也能够达到8.3×10⁶ g_PE·（mol_Fe·h）^-1。3种负载型催化剂催化烯烃聚合产物均成微球型,能够很好地复制载体的形貌。     

α-Ti(HPO4)2微球负载型催化剂的合成及其烯烃聚合催化性能

2种茂金属催化剂及1种后过渡金属催化剂分别被固载于经过甲基铝氧烷处理后的α-Ti（HPO₄）₂微球表面,制备得到3种微球负载型催化剂。在烯烃聚合反应过程中,3种负载型催化剂均表现出比硅胶负载型催化剂更高的催化活性。2种茂金属负载型催化剂在乙烯、丙烯聚合反应中的活性分别高达6.8×10⁷ g_PE·（mol_Zr·h）^-1和5.0×10⁷ g_PP·（mol_Zr·h）^-1,所产生的烯烃聚合产物分子量分布较窄（M_w/M_n<2.3）,表现出良好的单中心催化特性,而且丙烯聚合产物的等规度高达96.5%。负载型后过渡金属催化剂在乙烯聚合反应中的活性稍低,但也能够达到8.3×10⁶ g_PE·（mol_Fe·h）^-1。3种负载型催化剂催化烯烃聚合产物均成微球型,能够很好地复制载体的形貌。     

锌镍铝水滑石微球的制备及吸附性能

以Zn（NO₃）₂·6H₂O、Ni（NO₃）₂·6H₂O、Al（NO₃）₃·9H₂O和尿素为原料,采用一步水热法制备分散性良好的三元锌镍铝水滑石（ZnNiAl-LDHs）微球。通过X射线衍射（XRD）、傅里叶转换红外光谱（FTIR）、场发射扫描电镜（FESEM）、透射电镜（TEM）和氮气吸附-脱附等测试手段对样品的结构和形貌进行表征,并比较ZnNiAl-LDHs和ZnAl-LDHs对甲基橙（MO）的吸附性能。结果表明,ZnNiAl-LDHs是由纳米片组成、具有3D结构的微球,粒径为1~2.5 μm,比表面积为156 m²·g^-1,远大于ZnAl-LDHs的比表面积38 m²·g^-1;ZnNiAl-LDHs和ZnAl-LDHs对甲基橙的饱和吸附量分别为329.60和143.47 mg·g^-1,ZnNiAl-LDHs表现出更强的吸附能力,其吸附等温线和吸附动力学分别符合Langmuir等温线模型和准二级动力学模型。     

Cu、N共掺杂TiO2纳米管光催化重整甘油制备合成气

通过碱性水热-离子交换法制备了Cu、N共掺杂TiO₂纳米管(Cu/N-TNT),对其光催化重整甘油制备合成气性能进行了研究。结果表明,Cu/N-TNT具有富含氧空位(O_V)的管状结构,N以Ti-N形式取代部分O形成杂质能级,Cu以Cu²⁺形式掺杂在催化剂晶格间隙和表面,Cu、N共掺杂促进TiO₂表面电荷有效分离,有利于其光催化重整甘油制备合成气活性和选择性的提高。紫外光照射8 h时,掺Cu量为0.15%的Cu/N-TNT催化剂上CO和H₂产量分别为7.3和8.5 mmol·g^-1,是原始TiO₂的9.1和70.8倍,n_H2/n_CO从0.52提高为1.18,n_CO/n_CO2从0.21提高至0.42。Cu/N-TNT表面N和O_V为醛类脱羰和甲酸脱水生成CO提供反应活性位点,Cu作为浅势阱提高光生电子-空穴分离效率。光生空穴(h⁺)是光催化重整甘油制备合成气过程中的主要活性物种,大量羟基自由基(·OH)和超氧自由基(·O₂^-)会导致甘油过度氧化,使CO选择性降低。     

磁性壳聚糖复合微球的制备及其Cu2+吸附性能

以球磨后的粉煤灰磁珠（MS）颗粒为磁核,通过溶胶凝胶法和反相微乳液法依次包覆SiO₂和壳聚糖（CS）,制备了MS@SiO₂@CS磁性微球。利用扫描电镜及能量色散谱仪、热重分析仪、红外光谱仪、X射线衍射仪、振动样品磁强计对所得样品的结构和磁性进行了系统表征。结果表明,磁珠颗粒表面实现了逐层包覆,较均匀的分散于壳聚糖基体中,MS@SiO₂@CS微球的比饱和磁化强度可达7.04 emu·g^-1。Cu²⁺离子吸附实验表明,所得磁性壳聚糖微球对Cu²⁺具有良好的吸附能力,最大吸附量可达11.08 mg·g^-1;而且可通过磁选法高效固液分离。吸附动力学研究表明,MS@SiO₂@CS微球对Cu²⁺离子的吸附符合准二级动力学模型,以化学吸附为主。     

双功能化磁性纳米修复剂对多重金属的快速、高效钝化行为

采用“一锅法”制备了四氧化三铁/半胱氨酸（Fe₃O₄/Cys）磁性纳米微球,随后对Fe₃O₄/Cys进行亚氨基二乙酸（IDA）修饰得到Fe₃O₄/Cys/IDA磁性双功能化纳米微球。研究发现Fe₃O₄/Cys中的L-Cys是通过—SH基团接枝到Fe₃O₄表面的,随后IDA分子中的羧基与Fe₃O₄/Cys中的—NH₂形成酰胺键,最终形成多支链多羧基的Fe₃O₄/Cys/IDA磁性纳米修复剂。基于修复剂表面短支链-长支链交替的多羧基结构,实现了羧基基团的高密度接枝。同时,Fe₃O₄/Cys/IDA磁性纳米微球对Pb²⁺、Cd²⁺、Cu²⁺、Co²⁺、Ni²⁺、Zn²⁺为专性吸附,而对Hg²⁺属于非专性吸附,且吸附重金属后得到的钝化产物均表现了良好的稳定性。另外,Fe₃O₄/Cys/IDA对重金属离子的吸附符合Langmuir模型,属于单层均相吸附,其吸附过程符合准二级动力学模型,最大吸附量为49.05 mg·g^-1。     

Gd2(CO3)3:Eu@SiO2@APTES磁性-荧光双功能核壳微球的制备与性能

采用尿素均相沉淀法和Stöber法制备了氨基化SiO₂修饰的Gd₂(CO₃)₃:Eu顺磁性-荧光双功能微球。用扫描电镜(SEM)、红外光谱(IR)、X-射线粉末衍射(XRD)等测试手段对微球的结构和颗粒特征进行了分析。结果表明:微球为核壳结构,其Gd₂(CO₃)₃:Eu核平均直径为150nm左右,SiO₂壳层的厚度大约为30nm,分散性良好。磁性测试显示微球拥有良好的顺磁性,荧光光谱表明,在396nm紫外光激发下,微球在613nm发射较强荧光,属于Eu³⁺的特征发射,同时微球能成功标记NCIH460肺癌细胞,MTT毒性测试表明该法制备的双功能微球在100~400μg·mL^-1的浓度范围内无毒,表明其在生物应用方面的潜在应用价值。     

多级结构Mg3B2O6:Eu3+花状微球的制备、表征及其发光性能

以硝酸镁(Mg(NO₃)₂·6H₂O)和硼砂(Na₂B₄O₇·10H₂O)为原料,稀土元素Eu³⁺为激活剂,采用聚乙烯吡咯烷酮(PVP)辅助共沉淀法得到前驱体,并通过焙烧制备了多级结构Mg₃B₂O₆:Eu³⁺花状微球。通过XRD、SEM、TEM以及荧光光谱等手段分别对前驱体煅烧产物的结构、形貌、组成和荧光特性进行了表征。实验表明,在波长为393 nm激发光的激发下,所得到的产品在612 nm处有明显的特征发射峰,对应于Eu³⁺的(⁵D₀→⁷F₂)特征跃迁发射。这一荧光性质使得该材料在荧光灯、显示系统和光电设备应用中具有广阔的前景。同时我们还探讨了微球的形态、Eu³⁺的掺杂量及焙烧温度对花状微球荧光性能的影响。     

0D/1D AgI/MoO3 Z-scheme heterojunction photocatalyst: Highly efficient visible-light-driven photocatalyst for sulfamethoxazole degradation

Low dimension nano photocatalysts show great potential in the field of treating contaminated water for their large surface area and size effect. In this study, a 0D/1D AgI/MoO₃ Z-scheme photocatalyst with striking photocatalytic performance was constructed successfully. The one-dimensional MoO₃ nanobelts were prepared by a simple hydrothermal method, and then it was modified by AgI nanoparticles in a handy deposition approach. When choosing sulfamethoxazole (SMZ) as the target contaminant, the rate constant value of the optimal 0D/1D AgI/MoO₃ composite could hit up to 0.13 min⁻¹, which is nearly 22.4 times and 32.5 times as that of pure MoO₃ (0.0058 min⁻¹) and AgI (0.0040 min⁻¹), respectively. A series of detailed characterizations give evidences that the charge transfer in the composite followed Z scheme mechanism. Therefore, efficient separation/transfer and the remained high redox activity of photogenerated carriers played a vital role in the sharply enhanced photocatalytic properties. The possible degradation pathways of SMZ were proposed based on the intermediates detected by high-performance liquid chromatography-mass spectrometry (HPLC-MS). Meanwhile, the magnificent cyclic stability makes the material a promising material in the practical application.     

Radiation-induced conductivity in poly(phenylene vinylene) derivatives

Using the pulse-radiolysis time-resolved microwave conductivity technique the mobility and decay kinetics of radiation-induced charge carriers is studied in a series of poly(2,5-dialkoxy-phenylene vinylene) derivatives. The lower limit to the sum of the mobilities of the positive and negative charge carriers, Σμ_min, depends strongly on the alkoxy functionalization and ranges from 1.2·10⁻⁷ to 1.4·10⁻⁶ m²/V·s at room temperature. Σμ_min increases with the degree of order in the material. The after-pulse conductivity decay kinetics are disperse and are controlled by a combination of charge recombination and trapping.     

AgI/h-MoO_3异质结的构筑及其模拟燃油光催化氧化脱硫活性

利用沉积法获得了异质结AgI/h-MoO_3光催化剂,通过X射线衍射(XRD)、扫描电子显微镜(SEM)、光电子能谱(EDS)、X射线光电子能谱(XPS)、紫外-可见漫反射吸收光谱(UV-Vis-DRS)、光致发光(PL)、电化学阻抗(EIS)等方法对其物相组成、形貌、光吸收特性、光电化学性能等进行了表征。以噻吩的正辛烷溶液模拟催化裂化(FCC)汽油为探针考察了AgI/h-MoO_3光催化氧化脱硫活性,结果表明,AgI/h-MoO_3-18异质结在催化剂浓度为1.5 g·L~(-1),可见光照射2 h后,光催化氧化脱硫活性达98%。利用XRD、XPS、UV-Vis-DRS揭示了AgI/h-MoO_3光照后生成少量的金属Ag,使其结构转变为Z型AgI/Ag/h-MoO_3,有利于光生电子(e~-)转移。利用活性物种捕获实验、循环实验研究了AgI/h-MoO_3光催化氧化脱硫机理及其稳定性,实验结果表明:AgI/h-MoO_3不仅具有较高的光催化氧化脱硫活性,而且还有良好的稳定性。     

AgI/h-MoO3异质结的构筑及其模拟燃油光催化氧化脱硫活性

利用沉积法获得了异质结AgI/h-MoO₃光催化剂,通过X射线衍射（XRD）、扫描电子显微镜（SEM）、光电子能谱（EDS）、X射线光电子能谱（XPS）、紫外-可见漫反射吸收光谱（UV-Vis-DRS）、光致发光（PL）、电化学阻抗（EIS）等方法对其物相组成、形貌、光吸收特性、光电化学性能等进行了表征。以噻吩的正辛烷溶液模拟催化裂化（FCC）汽油为探针考察了AgI/h-MoO₃光催化氧化脱硫活性,结果表明,AgI/h-MoO₃-18异质结在催化剂浓度为1.5 g·L^-1,可见光照射2 h后,光催化氧化脱硫活性达98%。利用XRD、XPS、UV-Vis-DRS揭示了AgI/h-MoO₃光照后生成少量的金属Ag,使其结构转变为Z型AgI/Ag/h-MoO₃,有利于光生电子（e^-）转移。利用活性物种捕获实验、循环实验研究了AgI/h-MoO₃光催化氧化脱硫机理及其稳定性,实验结果表明：AgI/h-MoO₃不仅具有较高的光催化氧化脱硫活性,而且还有良好的稳定性。     

A zero differential overlap study of chemical binding in ammonia-borane and carbony l-borane

A cndo/2D study of the charge distribution obtained through Mulliken population analysis in the ground state of the title compounds shows that the features of charge distribution found by severalab initio calculations are fairly well reproduced by this method. The one-particle density, the interference density at the mid-point of the bond axis and the kinetic part of the interference energy calculated through the deorthogonalized density matrices over a wide range of intermolecular separation between the donor and the acceptor show that the one-particle density and the interference density steadily grow with decreasing internuclear separation, while the kinetic interference energy starts with negative value at large distance, then decreases and passes through a minima near but above the equilibrium distance and then increases rapidly below it conforming to the characteristic general behaviour of the kinetic component of Morse curve. The orbital pairwise interference density and the corresponding kinetic energy components reveal that the orbitals involved in the covalent binding are σ_2p AO of B and 2S and σ_2p AO of N and C atoms in H₃B-NH₃ and H₃B-CO respectively.     

ZnO修饰提升花状BiOBr的可见光催化降解罗丹明B性能

以Bi(NO3)3·5H2O、Zn(CH3COO)2·2H2O和NaBr为前驱体,采用简单溶剂热法制备BiOBr/ZnO三维花状微纳米复合材料.采用X射线衍射、扫描电子显微镜、X射线光子能谱、N2吸附-脱附、光致发光和电子顺磁共振等分析技术对其理化性质进行了表征.通过可见光催化降解罗丹明B(RhB)的实验测试了复合材料...     

FeNi层状双氢氧化物/TiO2复合光催化剂的制备及其制氢性能

层状双氢氧化物(LDH)的光生电子-空穴对易复合,虽然纳米薄片的结构促进了载流子分离,但其光催化效率仍然较低。我们利用LDH薄片结构的优势,将FeNi LDH和TiO₂通过静电自组装复合,设计制备出新型高效的FeNi LDH/TiO₂复合光催化材料,评价了其光催化分解水产氢性能。对其结构、光催化性能和光电化学等进行了详细表征。结果表明,FeNi LDH的高比表面积、复合物的异质结结构都有利于光生电荷的转移。光催化产氢结果表明,FeNi LDH/TiO₂复合材料的产氢速率(22.6mmol·g^-1·h^-1)分别比纯TiO₂(0.1 mmol·g^-1·h^-1)和FeNi LDH(0.05 mmol·g^-1·h^-1)提高了226和452倍,表明了异质结在提高LDH光催化效率方面的重要作用。     

Polyelectrolyte complex formation between poly(diallyldimethyl-ammonium chloride) and copolymers of acrylamide and sodium-acrylate

 The interaction between oppositely charged polyelectrolytes, in this study poly(diallyldimethylammonium chloride) (PDADMAC) and copolymers of acrylamide and sodium-acrylate differing in their chain length and charge density parameter (ξ) was investigated in relation to the molar charge ratio of anionic to cationic charges (n ₋/n ₊). The molecular weights of the polyelectrolytes used were 2.9·10⁵g/mol for PDADMAC and for the polyacrylamide copolymers 14 ·10⁶g/mol as well as 5·10⁵g/mol obtained by ultrasonic degradation of the high molecular weight copolymers. The charge density parameters of the polyanions used (ξ ^PR ) varied between 0.14 and 0.64. Complexation between PDADMAC and high molecular weight polyanions leads mainly to macroscopic phase separation whereas the degraded polyanions and PDADMAC formed soluble complexes as well as stable dispersions, if charge excess was available. Precipitates and dispersions were characterized by several methods such as element analysis, thermogravimetry, pyrolysis-GC/MS, PEL titration, ζ-potential measurements, determination of turbidity, particle size measurements and determination of carbon content (TOC).  All precipitated complexes include about 20% water and are of 1:1 stoichiometry concerning ionic binding. Investigations of dispersions confirm 1:1 stoichiometry of complex particles stabilized by excess polyelectrolyte and soluble complexes. It was also found that the particle size can be varied via the charge density parameter of the polyanions used in the range of negative charge excess. Received: 21 June 2001 Accepted: 9 October 2001     

A model study of the intermolecular interactions of amino acids in aqueous solution: The glycine-water system

We have performed calculations of the glycine zwitterion surrounded by water molecules with the help of the mutually consistent field (MCF) method and perturbation theoretical expressions. Two different models for the hydration shell have been chosen, the glycine·6H₂O and glycine·12H₂O complexes, representing the most probable first and second solvation shell, respectively. To calculate the exchange and charge transfer energy contributions we have applied approximative expressions derived from perturbation theory for weakly overlapping subunits. For the sake of comparison we also calculated the interaction energy in the supermolecule approach for the smaller of the two solvation complexes. Furthermore, we have investigated the part of the potential energy surface which is determined by varying the lengths of the hydrogen bonds between glycine and water in the complex glycine·12H₂O using the electrostatic approach. The exchange energy contribution to the interaction energy for different points on the surface was approximated with the help of an analytical expression fitted to three directly calculated points. For the charge transfer energy a polynomial expansion of second order was established on the basis of five values, computed with the aid of the perturbation theoretical expression. To get a more detailed insight in the relatively strong hydrogen bonds between the water molecules and the ionic hydrophilic parts of glycineab initio model studies on NH ₄ ⁺ ·3H₂O and HCOO⁻·3H₂O systems are reported.     

The quantum chemical calculation of NMR two-bond spin–spin coupling constants in the N?···H–OH?→?N–H···OH? switching

A quantum chemical study has been carried out to investigate the effects of the size of H₂O cluster and substituents (X = H, Me, OMe, CHO, NO, and NO₂) in the para position of the anilide ion on the two-bond spin–spin coupling constants (SSCCs) ^2h J _N···O across in the N–H–O switching at B3LYP/6-311 ++G(2d,2p) level of theory. The changes in ^2h J _N···O SSCCs due to variation of substituent and H₂O cluster size were well monitored by changes in binding energy, structural parameter, electron density topography, natural charge, charge transfer, and percentage of p-character of N atom in the C–N bond. Linear correlations were found between ^2h J _N···O and above-mentioned properties.