Fabrications of hollow nanocubes of Cu(2)O and Cu via reductive self-assembly of CuO nanocrystals

In this work, a template-free synthetic approach for generating single-crystalline hollow nanostructures has been described. Using the small optical band-gap cuprous oxide Cu(2)O as a model case, we demonstrate that, instead of normally known spherical aggregates, primary nanocrystalline particles can first self-aggregate into porous organized solids with a well-defined polyhedral shape according to the oriented attachment mechanism, during which chemical conversion can also be introduced. In contrast to the spherical aggregates, where the nanocrystallites are randomly joined together, the Cu(2)O nanocrystallites in the present case are well organized, maintaining a definite geometric shape and a global crystal symmetry. Due to the presence of intercrystallite space, hollowing and chemical conversion can also be carried out in order to create central space and change the chemical phase of nanostructured polyhedrons. It has been revealed that Ostwald ripening plays a key role in the solid evacuation process. Using this synthetic strategy, we have successfully prepared single-crystal-like Cu(2)O nanocubes and polycrystalline Cu nanocubes with hollow interiors. For the first time, we demonstrate that nanostructured polyhedrons of functional materials with desired interiors can be synthesized in solution via a combination of oriented attachment and Ostwald ripening processes.     

Measurement of non-methane hydrocarbons in Taipei city and their impact on ozone formation in relation to air quality

Air pollutants data from semi-continuous measurements at multiple sampling sites in Taipei metropolitan area of Taiwan was obtained by collecting air samples in canisters. The hydrocarbon composition was determined by using GC/MS and GC/FID. The air samples were pre-concentrated onto glass beads prior to separation by PLOT and DB-1 columns of GC. The method showed detection limit of <1 ppb and relative standard deviation in the range of 5-30% for different compounds. Aromatic hydrocarbons (toluene, benzene, etc.) and aliphatic hydrocarbons (ethylene, acetylene, propane, etc.) were correlated primarily to determine the source of emission. The estimated hydrocarbons were ranked according to their abundance and photochemical reactivity. The criteria pollutants, ozone and NO₂ were measured by UV-differential optical absorption spectroscopy (UV-DOAS), and were utilized to determine the relative importance of non-methane hydrocarbons (NMHC) and significant contribution of NO₂ in limiting ozone formation. The obtained results suggest that ozone formation in Taipei city is probably limited by the supply of non-methane hydrocarbons. The concentration profile of targeted pollutants was compared to other metropolitan areas to determine air quality and the pollutant sources.     

SiO2/Co3O4核壳催化剂对AP热分解的催化性能研究

采用改良的Stöber法制备粒径约为200 nm的单分散球形SiO₂颗粒,以此为内核,分别通过液相沉淀法和尿素均匀沉淀法制备包覆形式不同的新型SiO₂/Co₃O₄核壳式纳米催化剂。采用X-射线衍射分析(XRD)、透射电子显微镜(TEM)、红外光谱分析(IR)、拉曼光谱分析(Raman)、BET比表面积测试等手段对产物进行表征,利用差式扫描量热仪(DSC)考察SiO₂/Co₃O₄复合物对高氯酸铵(AP)热分解反应的催化作用,探讨不同包覆形式对其催化活性的影响。结果表明,两种方法制备得到的SiO₂/Co₃O₄复合物分别为层包覆和粒子包覆,比表面积大,具有明显的核壳结构,且粒子包覆形式的SiO₂/Co₃O₄对AP热分解反应的催化效果最好,使AP的高温分解温度降低了110 ℃,放热量增加了662 J·g^-1。     

基于衣康酸配体构筑的两个锌配合物的合成、结构和荧光性质

通过水热法合成了两种锌配位聚合物{[Zn(ic)(bip)]·2H₂O}n (1)和[Zn(ic)(bpe)]n (2)(H₂ic=衣康酸,bip=3,5-二(1-咪唑基)吡啶,bpe=1,2-二(4-吡啶基)乙烯),并通过X射线单晶衍射和元素分析对其结构进行了表征.配合物1和2均为含有一维金属-羧酸链的二维(4,4)格子层结构.此外,对它们的热重、粉末X射线衍射和固体荧光性能进行了考察.与配体bip相比,1的发射光谱发生了明显的蓝移(~78 nm),可能归因于配体到金属的电荷转移;2显示与游离的bpe配体相似的荧光性质,轻微的红移可能是因为与金属离子之间的配位作用导致的.     

Impact of Reaction Conditions on the Structures of Nickel(II) Complexes Based on 3‐(4‐Carboxyphenyl)propionic Acid

Two new nickel(II) complexes, [Ni(4, 4′‐bpy)(H₂O)₄]_n · n(cpp) · 0.5nH₂O ( 1 ) and [Ni(cpp)(4, 4′‐bpy)(H₂O)₂]_n ( 2 ) [4, 4′‐bpy = 4, 4′‐bipyridine, H₂cpp = 3‐(4‐carboxyphenyl)propionic acid] were synthesized and characterized by single‐crystal X‐ray diffraction, elemental analysis, IR spectroscopy, and thermal analysis. In complex 1 , Ni^II ions are bridged by 4, 4′‐bpy into 1D chains, and cpp ligands are not involved in the coordination, whereas in complex 2 , cpp ligands adopt a bis(monodentate) mode and link Ni^II ions into 2D (4, 4) grids with the help of 4, 4′‐bpy ligands. Triple interpenetration occurs, which results in the formation of a complicated 3D network. The difference in the structures of the two complexes can be attributed to the different reaction temperatures and bases.     

多级孔NiMo负载TS-1分子筛催化剂的制备及其加氢脱硫性能

钛硅(TS-1)分子筛的微孔孔道严重限制了其在复杂分子催化转化中的应用,为了克服这一问题,通过酸洗脱、碱刻蚀及二者相结合的方法制备了多级孔 TS-1 分子筛,并采用等体积共浸渍法制备了相应的 NiMo 负载型催化剂;使用 X 射线衍射(XRD)、N₂吸附-脱附、吡啶吸附红外光谱(Py-FTIR)、氢气程序升温还原(H₂-TPR)、X射线光电子能谱(XPS)和高分辨透射电子显微镜(HR-TEM)等方法对多级孔TS-1分子筛的理化性质进行了表征;以二苯并噻吩(DBT)为探针对催化剂的加氢脱硫(HDS)性能进行了评价。结果表明,和常规TS-1分子筛相比,多级孔TS-1分子筛保持了MFI拓扑结构,比表面积增大且具有介孔结构,分子筛表面形成了适量的Brønsted酸中心;相应催化剂上活性金属与载体间相互作用得以改善,MoS₂片晶长度和堆垛层数适宜,形成了更多的 NiMoS活性相;催化剂活性和选择性均有所提升,尤其是酸洗脱获得的 NiMo/AT-TS-1催化剂的活性相较未经处理的NiMo/TS-1催化剂提升了1.2倍,直接脱硫(DDS)路径选择性提升了22%。     

金纳米花介导的近红外热疗对人喉癌Hep-2细胞增殖的抑制作用

采用弱配体柠檬酸钠修饰的金纳米花为介导材料,考察了其对人喉癌Hep-2细胞的NIR热疗作用,结果表明,这种金纳米花材料具有良好的NIR光热转换性能,可有效抑制Hep-2细胞增殖.     

漩涡辅助-分散液液微萃取-高效液相色谱法测定沉积物中的多环芳烃

建立了漩涡辅助萃取(VAE)分散液液微萃取(DLLME)高效液相色普法(HPLC)测定水系沉积物中多环芳烃(PAHs)的方法。对萃取剂和分散剂的种类及体积、萃取时间、盐效应及pH值等参数进行了优化。在优化条件下,方法检出限为2.3～6.8 ng/g,线性范围为10～2100 ng/g,相关系数0.9986～0.9994,低、中、高3个浓度水平的平均加标回收率分别为85.2%±4.7%,85.0%±5.0%和85.0%±5.1%,平均相对标准偏差(RSD)分别为5.7%,6.1%和5.7%。采用本方法对实际沉积物样品中PAHs进行分析,所有沉积物样品中均检出PAHs,3组不同采样深度沉积物样品中PAHs平均含量分别为73.3,49 8和28.3 ng/g,平均加标回收率分别为84.8%±4.8%,83.1%±4.7%和84.6%±4.6%。     

混合钴源对Co-Pd/TiO2催化剂催化CH4-CO2两步梯阶转化法合成乙酸的性能影响

以混合钴源为前驱体, 采用等体积浸渍法制备了Co-Pd/TiO2催化剂, 考察了其对CH4和CO2梯阶转化直接合成乙酸的催化性能, 采用XRD, XPS, NH3-TPD和BET对催化剂进行了表征. 结果表明, 催化剂具有适宜的表面酸性、 高比表面积和孔结构, 有利于提高催化剂的活性. 在m(CoCl2)∶m=2∶5, m(Co)∶m(Pd)=2∶1, 常压, 150 ℃条件下, 乙酸的生成速率达到6.13 mg·g-1Cat·h-1, 选择性达到 81.6%, 分别比以单一Co源制备的催化剂提高了134%和16%.     

新型希夫碱型钳形人工受体的微波合成及其对中性分子的识别性能

以对苯二甲酸为起始原料,设计并合成了8个新型的芳环钳形人工受体(3a～3h),其结构经1H NMR,IR,ESI-MS和元素分析表征。利用UV-Vis滴定法初步考察了3a～3h对中性分子(邻苯二胺,间苯二胺,对苯二胺和二苯甲酮)的识别性能,结果表明3a～3h对其具有良好的识别性能。