A theoretical investigation on the structures and stabilities of C<Subscript>60</Subscript>X<Subscript>18</Subscript> and C<Subscript>70</Subscript>X<Subscript>10</Subscript> (X = H,F, Cl,and Br)

A density functional theory study was performed on fullerene derivatives C₆₀X₁₈ and C₇₀X₁₀ (X = H, F, Cl, and Br). The calculated results show that the lowest energy isomers are IPR-satisfying for C₆₀X₁₈ (X = H, F, Cl, and Br). It is found that the addition patterns of X (X = Cl and Br) are different from those of X (X = H and F) for C₆₀, demonstrating that the stability of fullerene derivatives is partly attributed to the steric repulsion and electronegativity of added atoms. However, the lowest energy isomers are IPR-violating for C₇₀X₁₀ (X = H, F, and Cl), suggesting that many more fullerene derivatives may violate the isolated pentagon rule.     

基于纳米材料修饰的高灵敏性L-苯丙氨酸印迹溶胶-凝胶传感器的研究

将氧化锌纳米膜(ZnO-NFs)、多壁碳纳米管(MWNTs)、纳米铜颗粒(Cu-NPs)和印迹溶胶-凝胶聚合物(MIP)依次修饰到碳电极(CE)表面,制备了一种对L-苯丙氨酸具有特异识别能力的印迹电化学传感器.采用电子扫描显微镜(SEM)对各修饰电极进行形貌表征;采用循环伏安法(CV)、示差脉冲伏安法(DPV)、安培时...     

加氢精制催化剂表面纳米棒束的电子显微镜研究

利用场发射扫描电镜(SEM)、高分辨透射电镜(HRTEM)、X射线能谱仪(EDX)和选区电子衍射(SAED)分析,对实验室硫化态加氢精制催化剂外表面上的纳米棒束的形貌、化学成分、晶体结构进行研究.SEM结果表明,该纳米棒束普遍分布于催化剂外表面并向外生长,纳米棒束形态较为规整,长度为500～1 500 nm,直径为20...     

DLLME-GC法同时测定尿样中4种芳烃类物质尿代产物

建立了分散液相微萃取-气相色谱法同时测定尿样中2,5-己二酮、苯酚、邻甲酚和对硝基酚的方法.确定了最佳色谱条件,优化了分散液相微萃取的萃取剂种类及用量、分散剂种类及用量、pH、萃取时间和加盐量等条件,实现了对尿样中四种有害物质尿代产物的同时提取和测定.在最佳实验条件下,建立4种组分的工作曲线,线性范围为0.02～8.3...     

杯冠衍生物BEHBCalixC6对铯离子萃取性能的研究

本文以杯冠BEHBCalixC6为萃取剂,二氯甲烷为稀释剂,通过液液萃取,研究了BEHBCalixC6对苦味酸铯的萃取性能.研究表明,随着主、客体摩尔比的增加,萃取率增大.在摩尔比50:1时,萃取率可以达到77%以上.考察了测量参比溶液、预饱和两相稀释剂、稀释剂种类和溶液中Na+浓度等因素对萃取率的影响.     

Atomic Imaging of Subsurface Interstitial Hydrogen and Insights into Surface Reactivity of Palladium Hydrides

Resolving interstitial hydrogen atoms at the surfaces and interfaces is crucial for understanding the mechanical and physicochemical properties of metal hydrides. Although palladium (Pd) hydrides hold important applications in hydrogen storage and electrocatalysis, the atomic position of interstitial hydrogen at Pd hydride near surfaces still remains undetermined. We report the first direct imaging of subsurface hydrogen atoms absorbed in Pd nanoparticles by using differentiated and integrated differential phase contrast within an aberration-corrected scanning transmission electron microscope. In contrast to the well-established octahedral interstitial sites for hydrogen in the bulk, subsurface hydrogen atoms are directly identified to occupy the tetrahedral interstices. DFT calculations show that the amount and the occupation type of subsurface hydrogen atoms play an indispensable role in fine-tuning the electronic structure and associated chemical reactivity of the Pd surface.     

石墨相氮化碳可见光下活化过一硫酸盐氧化降解光惰性邻苯二甲酸二甲酯的机理研究（英文）

近几年过一硫酸盐(PMS)活化技术备受关注,其中利用太阳能活化PMS具有可持续和环保的优势,但PMS本身不吸收可见光.因此,本文提出利用具有可见光响应的石墨相氮化碳(g-C3N4)激发产生光电子进而活化PMS.首先利用三聚氰胺前驱体通过热缩聚法制备g-C3N4,通过X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见光漫反射(UV-Vis)、荧光光谱(PL)、透射电镜(TEM)、N2吸附脱附测试(BET)、电化学等一系列方法对g-C3N4进行表征,研究其表面性质及光学性能.结果显示, g-C3N4具有典型的片层结构和可见光活性,禁带宽度为2.7 e V.本文选取光惰性的内分泌干扰物邻苯二甲酸二甲酯(DMP)为目标污染物,系统地研究了其降解动力学和降解机理.研究发现,在短波紫外光(254和300nm)照射下,直接光解和·OH参与的反应机理能实现DMP的光降解,而在可见光照射下g-C3N4介导的光催化过程不能使DMP分解;但当添加PMS时,体系主导自由基由·O2–转化为SO4·–和·OH,从而实现DMP的有效降解和矿化.研究还发现,高浓度的PMS和高剂量的g-C3N4均可以提高PMS的活化量和相应的DMP降解效率,但提高催化剂剂量的方式能更充分的利用PMS.尽管高浓度的DMP阻碍了PMS和光催化剂g-C3N4的有效接触,但可以提高PMS的利用率.当p H低于零电荷点(5.4)时, DMP的降解效率较高.此外,使用两种淬灭剂(乙醇和叔丁醇)与DMP进行竞争性实验,结合电子自旋共振检测,表明SO4·–和·OH都是体系主要的自由基.此外,还对g-C3N4的可持续性能进行考察,四次循环实验结果显示,该催化剂具有良好的可重复利用性.对DMP降解进行总有机碳测定,发现降低了19%.最后,利用液相色谱质谱联用对DMP降解产物进行定性定量分析,发现DMP主要通过SO4·–和·OH对苯环的攻击以及脂肪族链的氧化断键这两种途径进行降解.综上可见,利用可见光激发g-C3N4产生的光电子能有效活化PMS降解顽固型有机污染物,可为实现太阳能活化PMS技术提供有力的技术参考.     

通过赝反伽伐尼反应实现金纳米粒子模块替换

通过可控的方式精确调控纳米粒子的结构仍是一个富有挑战性和鼓舞人心的课题.尽管单原子或两、三个金属原子的精细调控已经在金纳米粒子中实现,涉及三个以上金属原子的取代（模块取代）还没有报道.本工作报道了环己硫醇配体保护的Au₄₈（CHT）₂₆的合成及其通过赝反伽伐尼过程的模块取代.单晶结构揭示模块取代的产物与母体团簇共用一个相似的Au₃₁（CHT）₁₂主体,但剩余部分不同（Au₆（CHT）₁₁ vs.Au₁₆（CHT）₁₄）.一个有趣的发现是模块取代抑制了Au₄₈（CHT）₂₆的光热过程,却增强了它的发射,赋予了所合成团簇更好的双（多）功能应用潜力.光热效应的减弱和发射的增强也暗示了这两种作用能够彼此至少部分转化,对于研究这两种效应之间的相互影响也具有重要的启示.     

Structurally Interesting Diarymethane Derivatives from Securidaca inappendiculata

Securines A—E, three dimeric diarymethane derivatives ( 1 — 3 ) and two enantiomeric diarymethane derivative monomers ( 4 and 5 ), were isolated and characterized from the medicinal plant Securidaca inappendiculata. Compounds 1 and 2 are a pair of enantiomeric diarymethane derivative dimers, and compound 3 is a mesomeric diarymethane derivative dimer. Their structures were determined by a combination of spectroscopic data, X‐ray crystallography, electronic circular dichroism (ECD) analysis, and computational ECD calculations. Dimeric compounds 1 — 3 showed moderate antiplasmodial activities with IC₅₀ values of 0.9, 1.4, and 1.5 μM, respectively.     

2 D Manganese Vanadate Nanoflakes as High‐Performance Anode for Lithium‐Ion Batteries

Nanometer‐sized flakes of MnV₂O₆ were synthesized by a hydrothermal method. No surfactant, expensive metal salt, or alkali reagent was used. These MnV₂O₆ nanoflakes present a high discharge capacity of 768 mA h g^?1 at 200 mA g^?1, good rate capacity, and excellent cycling stability. Further investigation demonstrates that the nanoflake structure and the specific crystal structure make the prepared MnV₂O₆ a suitable material for lithium‐ion batteries.