Hydrogen in Palladium and Storage Properties of Related Nanomaterials: Size,Shape, Alloying,and Metal-Organic Framework Coating Effects

One of the key issues for an upcoming hydrogen energy-based society is to develop highly efficient hydrogen-storage materials. Among the many hydrogen-storage materials reported, transition-metal hydrides can reversibly absorb and desorb hydrogen, and have thus attracted much interest from fundamental science to applications. In particular, the Pd−H system is a simple and classical metal-hydrogen system, providing a platform suitable for a thorough understanding of ways of controlling the hydrogen-storage properties of materials. By contrast, metal nanoparticles have been recently studied for hydrogen storage because of their unique properties and the degrees of freedom which cannot be observed in bulk, i. e., the size, shape, alloying, and surface coating. In this review, we overview the effects of such degrees of freedom on the hydrogen-storage properties of Pd-related nanomaterials, based on the fundamental science of bulk Pd−H. We shall show that sufficiently understanding the nature of the interaction between hydrogen and host materials enables us to control the hydrogen-storage properties though the electronic-structure control of materials.     

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%。     

螺吡喃功能化UiO-66光响应吸附剂的制备及其性能

将光响应分子甲基螺吡喃SP-CH₃引入UiO-66的非极性孔笼中,构筑吸附活性位可光控调节的光响应吸附剂。SP-CH₃功能化的吸附剂完好保留了载体UiO-66的骨架和孔道结构。以阴离子染料甲基橙为探针,研究了吸附剂在不同光照条件下的吸附和解吸性能。结果表明,经紫外光照后,吸附剂对甲基橙的吸附量为41.99 mg·g^-1,相较于可见光照后样品的吸附量提升57.56%,吸附作用增强;经可见光照后,甲基橙的脱附量为81.6%。本策略通过光照刺激改变UiO-66孔笼中SP-CH₃的构型及表面电荷性质,即对吸附活性位进行光控调节,在不同光照条件下实现对吸附质的高效吸附和有效脱附。     

Computational studies on the injection,transport, absorption,and phosphoresce properties of a series of cationic iridium (III) complexes [Ir(C∧N)2(L)2]+ (C∧N = ppy,tpy, dfppy,bzq)

Quantum chemistry methods are applied to investigate the electronic structures, injection and transport properties, absorption and phosphorescence mechanism of a series of Iridium (III) complexes [Ir(C∧N)₂(L)₂]⁺ (L = 4‐pyCO₂Et; C∧N = 2‐phenylpyridine, 1 ; 2‐(4‐tolyl)pyridine, 2 ; 2‐(4,6‐difluorophenyl)pyridimato, 3 ; benzoquinoline, 4 ), which may be used as emitters on organic light emitting diodes (OLEDs). Calculations of ionization potentials and electron affinities are used to evaluate the injection abilities of holes and electrons into these complexes. The reorganization energy (λ) calculations show that the four complexes are suitable as emitters in OLEDs. The absorptions and emissions can be tuned by adding substituent to the ppy ligand or extending the π‐conjugation effect of the C∧N ligand, and quantum yields of 1 – 4 are investigated. In addition, no solvent effect is observed in the absorption and emission spectra. © 2012 Wiley Periodicals, Inc.     

桑色素及其配合物与DNA作用的研究

桑色素 (Morin)是黄酮类化合物 ,具有一定的抗肿瘤活性 [1] .前文 [2 ] 以桑色素为配体合成了 6种过渡金属的配合物 ,并研究了这些配合物与配体对超氧阴离子自由基的清除作用和抗肿瘤活性 .研究表明 ,配合物对超氧阴离子自由基的清除作用明显高于配体 ,桑色素合铜 ( )和桑色素合锌 ( )配合物对 Hep- 2 ,BHK- 2 1和 HL - 6 0癌细胞瘤株的抑制作用强于配体 .配合物具有比单一有效成分更显著的药效 [3 ,4 ] .本文采用荧光方法和电化学方法研究了桑色素和抗肿瘤活性较强的桑色素合铜 ( )、桑色素合锌 ( )与 DNA在生理条件下的相互作用 ,试图…     

薄层色谱法定量测定氮酮

对薄层色谱法测定氮酮的操作条件进行了探索。选择了以丙酮为溶剂对样品进行溶解，以石油醚-异丙醚-异丙醇(体积比6：1：1)为展开剂上行展开，在碘蒸汽中显色，密封展板后进行测量。甚定性检测结果各组分分离良好，斑点集中且清晰。定量检测线性范调为15～250μg，线性方程Y(μA)=869．7514 101．9879X(μg)(n=8)，相关系数为0．9986，加标回收率为101．2％，仪器精密度为1．21％，同板精密度为1.82％，均满足薄层定量分析的要求。     

卤代化合物的光化学反应研究进展

介绍近年来卤代化合物在光照射下的偶联反应、醇解反应、消去反应、开环反 应，尤其是卤代杂环化合物的光化学反应，得到了许多用热反应或催化反应无法替 代的具有生物(理)活性的中间体．     

THE COMPARISON OF LANZHOU LOESS PROFILE WITH VOSTOK ICE CORE IN ANTARCTICA OVER THE LAST GLACIATION CYCLE

Loess near Lanzhou in the late Pleistocene is very sensitive to climatic fluctuations. The Beiyuan terrace profile in Linxia City, of which the curve of susceptibility tallies with the trend of isotopic curves of Vostok 2083 m ice core in Antarctica, is 35m thick. There are five layers of paleosols under Malan loess(L_1). Upper three layers (S_(1-a),S(1-b)and S_(1-c) correspond to three warm stages in last interglaciation, Interstadial of Last Glacial (C stage in Antarctic ice core)was clearly recorded in the Beiyuan profile, in which three layers of paleosols and two of loess were formed. The lowest section of the profile belongs to penultimate glaciation, in which fossils of cold-drought-resistant mammal and mollusc have been discovered.     

SiO2与Keggin杂多酸相互作用的研究

采用经典酸化与乙醚萃取相结合的方法，制备了Keggin型杂多酸H3PMo12O40，并以SiO2为载体制备了经不同温度焙烧的负载型杂多酸样品，利用TG、DTA、IR、XPS、NH3－TPD等手段，对负载前后的杂多酸样品进行了表征；考察了SiO2与杂多酸之间的相互作用以及载体对杂多酸酸性的影响，研究发现，SiO2载体的引入，可以有效改善杂多酸的热稳定性，焙烧温度的升高，会显著降低杂多酸的酸性，并提出SiO2杂多酸的相互作用方式。     

溶胶凝胶法制氧化铝负载铜基超细粒子催化剂的研究

采用溶胶凝胶法制氧化铝负载铜基超细粒子催化剂的制备了氧化铝负载的铜基超细粒子催化剂，用ＴＧ－ＤＴＡ，ＸＲＤ，ＢＥＴ以及ＴＥＭ等技术手段，对催化剂的物相结构，表面孔结构，粒子形貌以及催化性能等进行了研究。结果表明，利用溶胶凝胶法，可以直接帛备出高比表面积，低堆积密度的纤维状纳米级负载型Ｃｕ／Ａｌ２Ｏ３超细粒子；活性组分以远低于纳米级的微晶粒子簇状态，均匀地分散在纳米级氧化铝载体表面上，而且在低于５０