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901.
Kohsuke Mori Xufang Qian Yasutaka Kuwahara Yu Horiuchi Takashi Kamegawa Yixin Zhao Catherine Louis Hiromi Yamashita 《Chemical record (New York, N.Y.)》2020,20(7):660-671
Nanoporous silica solids can offer opportunities for hosting photocatalytic components such as various tetra‐coordinated transition metal ions to form systems referred to as “single‐site photocatalysts”. Under UV/visible‐light irradiation, they form charge transfer excited states, which exhibit a localized charge separation and thus behave differently from those of bulk semiconductor photocatalysts exemplified by TiO2. This account presents an overview of the design of advanced functional materials based on the unique photo‐excited mechanisms of single‐site photocatalysts. Firstly, the incorporation of single‐site photocatalysts within transparent porous silica films will be introduced, which exhibit not only unique photocatalytic properties, but also high surface hydrophilicity with self‐cleaning and antifogging applications. Secondary, photo‐assisted deposition (PAD) of metal precursors on single‐site photocatalysts opens up a new route to prepare nanoparticles. Thirdly, visible light sensitive photocatalysts with single and/or binary oxides moieties can be prepared so as to use solar light, the ideal energy source. 相似文献
902.
《Arabian Journal of Chemistry》2020,13(7):6174-6183
Lung cancer is the widespread carcinogenesis in men and the third most familiar cancer in women. It is one of the mostly aggressive human cancers, which is responsible for around 1.4 million deaths per annum and has utmost mortality and incidence with 1.8 million new incidences and 1.6 million new deaths yearly. In this present study, we have evaluated the anticancer potential of zinc oxide nanopartices (ZnONPs) synthesized from a root extract of Euphorbia fischeriana (EF), through the apoptosis signaling markers in A549 lung cancer cells. The synthesized EF-ZnONPs were evaluated through the transmission electron microscope (TEM), Fourier transform infra red (FTIR), UV–visible spectroscopy and dynamic light scattering (DLS) techniques. The EF-ZnONPs were assessed for their cytotoxicity activity towards A549 cells by MTT test. The induction of apoptosis was analysed by the mitochondria membrane potential (MMP), reactive oxygen species (ROS), cell migration and dual staining. Furthermore, pro and anti-apoptotic signaling protein expression was evaluated by western blotting method. We found the bioformulated EF-ZnONPs has a spherical morphology and revealed the existence of diverse bioactive compounds. Also we found the cytotoxic effect of EF-ZnONPs. Apoptosis was activated by the EF-ZnONPs with improved ROS, decreased MMP, inhibited cell migration and altered dual staining was observed. Furthermore, the diminished expression of anti-apoptotic protein Bcl-2 was noted. In this study, we observed the formulation, characterization and anticancer potency of ZnONPs of EF plant extract (EF-ZnONPs) was useful for treatments of lung cancer. 相似文献
903.
《Arabian Journal of Chemistry》2020,13(8):6544-6551
Prevalent contamination of water by cadmium ion (Cd2+) brings environmental risk, which threatening to human health including renal dysfunction, reduced lung capacity, and some cancers. It calls for rapid, sensitive and selective protocol to analyze Cd2+ on field. In this work, specific Raman probe is rationally designed by gold nanoparticles (AuNPs) functionalized with tripeptide glutathione (GSH) and Rhodamine 6G (R6G) (denoted as R6G/GSH/AuNPs), which is explored for indirectly determining trace Cd2+ in river water. Based on chelating interaction between GSH and Cd2+ to form tetrahedral Cd(SG)4, which trends easy detachment from R6G/GSH/AuNPs. With increasing Cd2+ concentration, the Raman probe without protection of GSH happens due aggregation and Raman signal of R6G increases correspondingly. The R6G/GSH/AuNPs-based Raman detection of Cd2+ in river water shows rapidness, excellent sensitivity, selectivity and good repeatability. Limit of detection of 10 ppb with a widely linear range of 0.5–20 ppm could be achieved. It could be perspective that such Raman probe could be extended to be used for on-site monitoring trace Cd2+ in river water system. 相似文献
904.
The electrochemical oxidation of single colloidal Ag nanoparticles (NPs) at an electrode surface has previously been studied as an in situ particle-sizing methodology. However, the discovery of multipeak amperometric behavior in 2017 sparked new interest toward understanding the precise physical mechanism of the manner in which a freely diffusing Ag NP interacts with the electrode surface. Random walk simulations, unique electrochemical experiments, and correlated optical/spectroscopic techniques have revealed exciting new results regarding the physical and chemical processes occurring on single NP collision. 相似文献
905.
K. Meienberg T. Malinina Z. Nguyen M. A. Glaser N. A. Clark 《Molecular Crystals and Liquid Crystals》2015,611(1):14-20
We observe directly the diffusion and aggregation of buckyball clusters dispersed in thin, freely-suspended films of smectic liquid crystal using reflected light microscopy. The buckyballs at early times are barely resolvable, nanoscale clusters, which diffuse stochastically in the film. Clusters eventually coalesce to form micron-scale, fractal aggregates whose effective radius increases approximately linearly with time, so that after several days, millimeter-size fractals extend across the entire film. The measured fractal dimension of these final networks suggests that the aggregation of the buckyball clusters in the film is a diffusion-limited process. 相似文献
906.
A Palladium‐Nanoparticle and Silicon‐Nanowire‐Array Hybrid: A Platform for Catalytic Heterogeneous Reactions 下载免费PDF全文
Dr. Yoichi M. A. Yamada Yoshinari Yuyama Dr. Takuma Sato Dr. Shigenori Fujikawa Dr. Yasuhiro Uozumi 《Angewandte Chemie (International ed. in English)》2014,53(1):127-131
We report the development of a silicon nanowire array‐stabilized palladium nanoparticle catalyst, SiNA‐Pd. Its use in the palladium‐catalyzed Mizoroki‐Heck reaction, the hydrogenation of an alkene, the hydrogenolysis of nitrobenzene, the hydrosilylation of an α,β‐unsaturated ketone, and the C‐H bond functionalization reactions of thiophenes and indoles achieved a quantitative production with high reusability. The catalytic activity reached several hundred‐mol ppb of palladium, reaching a TON of 2 000 000. 相似文献
907.
Conductance switching through chemical modification of a molecular bridge is a major goal in molecular electronics, with the potential to lead to molecule‐based functional devices. In terms of switching speed, mechanisms that rely on only minor rearrangements of molecular structures are particularly promising. We demonstrate, based on density functional theory calculations combined with a coherent tunneling approach, how protonation and deprotonation of amine‐substituted or amine‐bridged model molecular wires can switch off and on π‐sites and thus: a) remove or introduce interference features in the electron transmission, and b) decrease or increase coupling along a chain. This mechanism may also be relevant for interactions between molecular bridges and metal cations, for example, in sensor applications. 相似文献
908.
以溶胶-凝胶伴随相分离法制备的阶层多孔二氧化硅作为载体,3-氨丙基三乙氧基硅烷(APTES)为改性剂,乙醇为还原剂,在阶层多孔二氧化硅固体骨架上进行银纳米颗粒均匀负载.利用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、汞压、N2吸附/脱附、X射线光电子能谱(XPS)等测试技术对银纳米颗粒负载阶层多孔二氧化硅进行了表征,探讨了APTES表面改性、乙醇还原机理以及银纳米颗粒负载块体的孔结构特征变化规律.结果表明:APTES表面改性将氨基接枝于阶层骨架上,氨基与银离子形成银氨离子,银氨离子经乙醇还原后将平均粒径约16 nm的银纳米颗粒成功负载于二氧化硅的大孔及介孔内部;负载后的阶层多孔块体的大孔骨架未受到破坏,但其比表面积由418 m2·g-1下降到254m2·g-1,两次还原负载能提高银纳米颗粒的负载量. 相似文献
909.
910.
采用溶胶-凝胶法和光还原沉积法制备出Ag改性的纳米BiFeO3粒子,对复合材料进行了FESEM、XRD、XPS、FTIR、UVVis/DRS等分析和表征。考察了波长365 nm以上的光照下,铁磁性材料的空间选择性光化学反应对复合材料的结构、形貌以及光谱性质的影响。以罗丹明B为模拟污染物,考察了纳米Ag-BiFeO3粒子的可见光光催化活性以及稳定性。结果表明:通过光化学沉积,不仅增强了BiFeO3在200~800 nm光照下的响应,而且抑制了光腐蚀现象,提高了BiFeO3的稳定性。在波长大于400nm的光照射12 h后单纯纳米BiFeO3粒子对罗丹明B脱色率约为74%,而Ag-BiFeO3复合材料6 h后约为90%,并且重复使用3次后光催化效果基本不变。 相似文献