Synthesis, characterization, and catalytic performance of copper-containing SBA-15 in the phenol hydroxylation

A series of copper-containing SBA-15 samples were successfully synthesized via evaporation-induced self-assembly route. The resulting materials were characterized by X-ray diffraction (XRD), (29)Si MAS NMR spectroscopy, transmission electron microscopy (TEM), N(2) sorption, inductively coupling plasma-atomic emission spectrometer (ICP-AES), thermogravimetry, and differential thermal analysis (TG-DTA), Fourier-transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectra (UV-vis) and X-ray photoelectron spectroscopy (XPS). The results indicated that: (1) all the samples exhibited typical hexagonal arrangement of mesoporous structure; (2) copper ions could be incorporated into the framework of SBA-15; (3) the addition of urea in the hydrothermal stage efficiently reduced the leaching of copper and improved the thermal stability of the mesoporous materials. Catalytic performances of the obtained materials were evaluated in the hydroxylation of phenol with H(2)O(2). The catalytic tests showed that the synthesized materials exhibited high activity for this reaction and copper ions in the framework were more active than copper species in the extra-framework position. The nitric acid treatment on the samples removed the bulk CuO species, which resulted in a dramatic increase in the catalytic activity.     

Strong excitonic effect in organic–inorganic hybrid crystals

We investigate the optical properties of the hybrid crystal ZnTe(C₂H₈N₂)_0.5 from first principles. The excitonic effect is included by solving the Bethe–Salpeter equation for the two-particle Green's function. The inorganic ZnTe acts as optical active layer and the excitonic wave function is confined within it by C₂H₈N₂ layers. Due to the confinement of electronic states, electron–hole interaction within ZnTe layers is enhanced and the absorption spectra are thus changed drastically. The exciton binding energies are 0.54 and 0.42 eV for α and β structures, respectively. The calculated quasiparticle gap of the β structure is 3.68 eV.     

氧化锌多孔微米花的制备及其气敏性能研究

具有大比表面积和丰富表面缺陷的三维多孔纳米材料在气体传感中极具潜力. 通过液相共沉淀法制备了三维微米花状锌基前驱物,于400 ℃热处理即转化为ZnO多孔微米花,它继承了锌基前驱物的外观形貌,但片状“花瓣”的表面形成大量无序孔洞,使得ZnO多孔微米花具有大比表面积（31.3 m²·g^-1）和丰富的表面缺陷. 鉴于ZnO多孔微米花的独特微观形貌结构,用其构建的气体传感器对乙醇气体表现出最佳工作温度低、灵敏度高、响应（恢复）快速等优点,与文献报道的ZnO基乙醇气体传感器相比处于领先水平. 结合其制备过程简单、成本低等优点,ZnO多孔微米花在气体传感领域有潜在的应用价值.     

Preparation of F-doped titania nanoparticles with a highly thermally stable anatase phase by alcoholysis of TiCl4

Pure anatase is a metastable phase and inclined to (transform) be transformed into rutile structure under heating over than 500 °C, which limits its suitability for high-temperature applications. Hitherto much research efforts have been made to increase the stability temperature of anatase structure. However, metallic doping usually introduced metallic oxides into titania at high temperature, and many nonmetallic doping are not competent for increasing the stability temperature of anatase structure up to 900 °C. In this study, F-doped anatase TiO₂ nanoparticles were conveniently prepared via the alcoholysis of TiCl₄ and the as-prepared product shows very high stability temperature up to 1000 °C before being transformed into rutile structure phase. On the basis of XPS results of F-doped titania annealed at different temperature, it is learned that the F atoms were anchored on the crystal planes of anatase in favor of decreasing the energy faces of anatase and stabilizing the anatase structure till annealed at 1300 °C all the anatase were transformed into rutile phase.     

温和条件下钌/氮掺杂碳纳米笼的苯乙酮选择性催化加氢性能

共轭羰基化合物的羰基选择性加氢反应被广泛用于制备重要的药物和化学中间体.利用氮掺杂碳纳米笼（hNCNC）大的比表面积和掺杂氮原子的锚定作用,构建了10 wt% Ru负载量的Ru/hNCNC催化剂,尺寸约2.4 nm的Ru纳米颗粒高度均匀地分散在hNCNC表面.用于催化苯乙酮选择性加氢制1-苯乙醇,在50.0℃、2.0 MPa H₂的温和条件下,展现出优异的催化加氢性能：反应2.0 h后的苯乙酮转化率和1-苯乙醇选择性分别达到96.2%和95.8%,远优于未掺杂碳纳米笼（hCNC）和活性炭负载的Ru催化剂;循环使用6次后,其苯乙酮转化率仅略有下降（从96.2%到94.0%）,明显优于Ru/hCNC.Ru/hNCNC的优异催化性能可归因于：hNCNC大的比表面积和掺杂氮原子的锚定作用有利于Ru纳米粒子的分散和固载、独特的微孔-介孔-大孔共存的分级孔结构有利于传质、掺杂氮原子有效调变了Ru催化剂的电子结构.     

基于双间苯-32-冠-10穴醚超分子组装体的设计与构筑

由于具有三维空腔结构及良好的应用前景, 穴醚逐渐成为超分子研究领域的热点之一. 近年来, 我们课题组设计合成了一系列基于双间苯-32-冠-10穴醚主体分子, 并利用这些穴醚分子构筑了不同的超分子组装体. 首先, 将双硫代四硫富瓦烯(STTFS)引入到穴醚的第三个臂上, 成功构筑了具有氧化还原响应性的穴醚主体分子. 该穴醚与客体间的解离-穿环过程可以利用STTFS的氧化态来进行控制; 其次, 设计合成了两种含有P=O官能团桥连的穴醚, 在固态结构中得到了近似线型和Z字型的不同超分子聚[2]准轮烷; 最后, 合成了具有两种不同性质空腔的柱[5]芳烃稠合穴醚主体分子, 该穴醚通过正交作用同时络合两个不同的客体分子. 基于两种不同主客体作用力, 我们构筑了一种新型的超分子聚合物. 以上研究为分子器件和超分子材料的进一步研究奠定了良好的基础.     

热解聚苯胺/碳纳米笼复合物制备氮掺杂碳材料及其氧还原性能研究

将含氮聚合物聚苯胺(PANI)均匀地担载到具有大比表面积、多级孔结构和高导电性的3D碳纳米笼(CNC)表面, 再热解PANI制得了N掺杂位富集于表面、且具有优良导电性的碳基纳米材料. 通过改变热解温度和前驱物中PANI的含量, 对热解产物的表面N含量和导电性进行了调控. 优化得到的NCNC-2-900催化剂具有优异的氧还原反应(ORR)催化性能, 其起始电位高(-46 mV vs Ag/AgCl), 明显优于体相N掺杂的CNC (-105 mV), 且稳定性好(运行10 h后仍保留96%活性). 该结果表明在保持良好导电性的同时增加表面N掺杂位是提高碳基材料ORR活性的有效途径.     

高倍率锂离子电池负极材料:氮掺杂碳纳米笼

锂离子电池具有能量密度高和循环性好等优点, 广泛应用于小型移动设备等领域, 但尚不能满足需要兼具高容量和高倍率性能的应用要求. 以兼具高比表面积、氮含量高且可调、良好石墨化程度、多尺度分级结构(含孔结构)、有微孔通道的寡层笼壁结构等特征的氮掺杂碳纳米笼(NCNC)为锂离子电池负极材料, 展现出高的比容量、优异的倍率性能和稳定性, 譬如: 在0.1 A·g^-1小电流密度下, NCNC800的循环稳定的充电比容量可以高达约900 mAh·g^-1, 显著优于商业石墨; 在20.0 A·g^-1大电流密度下, 循环500圈后的可逆比容量仍能稳定在约135 mAh·g^-1. 如此优异的电化学性能可归因于NCNC的结构特征, 如高比表面积、良好石墨化程度、独特介观结构和孔结构, 这些特征有利于锂离子传输、电解液渗透和电子传导等. 这为开发高倍率和高比容量的锂离子电池负极材料提供思路.     

Fully optimized implementation of the cluster-in-molecule local correlation approach for electron correlation calculations of large systems

A fully optimized implementation of the cluster-in-molecule (CIM) local correlation method for faster and more accurate electron correlation calculations of large systems is reported. The speedup comes from the new procedure of constructing virtual localized molecular orbitals of clusters. In the new procedure, Boughton–Pulay projection method is employed instead of a much more expensive Boys localization procedure. In addition, basis set superposition error correction for binding energy calculations and parallelized electron correlation calculations of clusters are now implemented. Benchmark calculations and illustrative applications at the Møller–Plesset perturbation theory, coupled cluster singles and doubles (CCSD), and CCSD with perturbative triples correction levels show that this newly optimized CIM approach is a reliable theoretical tool for electron correlation calculations of various large chemical systems. © 2018 Wiley Periodicals, Inc.     

Pd/CuxCo3-xOn界面的可控制备及高效催化甲苯燃烧反应

采用水热合成法制备了形貌规整且主要暴露晶面为(112)面的Co_3O_4六角片,在此基础上掺杂了适量的Cu元素,并且可控沉积了窄尺寸分布的Pd粒子。制备过程简单、绿色且产率高。所得材料应用于催化甲苯完全氧化反应时表现出优异的催化性能,其中Pd/h-Cu_(0.18)Co_(2.82)O_n的T_(90)(甲苯的转化率达到90%时的反应温度)低至198℃。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、比表面积测试(BET)、H2程序升温还原(H2-TPR)、X射线光电子能谱(XPS)对催化剂的结构和理化性质进行了表征。结果表明,适宜量的Cu掺杂后Co_3O_4基底氧空位增多,活化氧的能力增强,表面存在丰富的吸附氧物种,表现出与贵金属基催化剂相媲美的催化活性。引入的Pd组分主要以PdO形式存在,基底Cu掺杂进一步提升了Pd的氧化态,表面高反应性的氧种更多,反应活性更高。