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61.
Controlling Proton and Electron Transfer Rates to Enhance the Activity of an Oxygen Reduction Electrocatalyst
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Rajendra P. Gautam Yi Teng Lee Gabriel L. Herman Cynthia M. Moreno Prof. Dr. Edmund C. M. Tse Prof. Dr. Christopher J. Barile 《Angewandte Chemie (International ed. in English)》2018,57(41):13480-13483
An electrochemical approach is developed that allows for the control of both proton and electron transfer rates in the O2 reduction reaction (ORR). A dinuclear Cu ORR catalyst was prepared that can be covalently attached to thiol‐based self‐assembled monolayers (SAMs) on Au electrodes using azide–alkyne click chemistry. Using this architecture, the electron transfer rate to the catalyst is modulated by changing the length of the SAM, and the proton transfer rate to the catalyst is controlled with an appended lipid membrane modified with proton carriers. By tuning the relative rates of proton and electron transfer, the current density of the lipid‐covered catalyst is enhanced without altering its core molecular structure. This electrochemical platform will help identify optimal thermodynamic and kinetic parameters for ORR catalysts and catalysts of other reactions that involve the transfer of both protons and electrons. 相似文献
62.
Cover Picture: Size‐Controlled Formation of Noble‐Metal Nanoparticles in Aqueous Solution with a Thiol‐Free Tripeptide (Angew. Chem. Int. Ed. 30/2016)
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63.
Size‐Controlled Formation of Noble‐Metal Nanoparticles in Aqueous Solution with a Thiol‐Free Tripeptide
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Stefano Corra Dr. Urszula Lewandowska Dr. Edmondo M. Benetti Prof. Dr. Helma Wennemers 《Angewandte Chemie (International ed. in English)》2016,55(30):8542-8545
A combinatorial screening revealed the peptide H‐His‐d ‐Leu‐d ‐Asp‐NH2 ( 1 ) as an additive for the generation of monodisperse, water‐soluble palladium nanoparticles with average diameters of 3 nm and stabilities of over 9 months. The tripeptide proved to be also applicable for the size‐controlled formation of other noble‐metal nanoparticles (Pt and Au). Studies with close analogues of peptide 1 revealed a specific role of each of the three amino acids for the formation and stabilization of the nanoparticles. These data combined with microscopic and spectroscopic analyses provided insight into the structure of the self‐assembled peptidic monolayer around the metal core. The results open interesting prospects for the development of functionalized metal nanoparticles. 相似文献
64.
为了满足超辐射发光管的短波长应用,采用InAlGaAs/AlGaAs量子点有源区和干法刻蚀工艺制备了短波长弯曲波导超辐射发光管。在1.6A脉冲电流注入下,器件峰值输出功率为29mW,中心波长为880nm,光谱半高宽为20.3nm。比较了干法刻蚀工艺和湿法腐蚀工艺对超辐射发光管器件性能的影响。在1.6A脉冲电流注入下,湿法腐蚀制备的器件峰值输出功率仅为7mW。与湿法腐蚀相比,干法刻蚀可以精确控制波导形状和参数,降低波导损耗,有效增大器件输出功率。 相似文献
65.
Gold electrodes were chemically modified with a phosphate ester monolayer designed to mimic biological ion-channel membranes.
Cyclic voltammograms of Fe(CN)6
3− as electroactive marker were measured in the presence of various types of analyte cations. Whereas in the absence of analyte
cations the marker reduction was hindered by electrostatic repulsion between the marker anions and phosphate groups of the
receptor monolayer, binding of di-and trications to the monolayer resulted in large increases of the reduction current. Trivalent
cations could be detected down to the submicromolar concentration range with excellent selectivities over alkali metal ions.
Also divalent cations were well discriminated and similar responses as to trivalent cations were only observed if their concentration
exceeded that of the trivalent cations by about two orders of magnitudes.
Received August 24, 1998. Revision March 10, 1999. 相似文献
66.
67.
铜卟啉-L-半胱氨酸自组装复合膜修饰电极的制备及电化学性能研究 总被引:4,自引:2,他引:2
利用电化学扫描法在L 半胱氨酸(Cys)自组装单分子膜修饰金电极表面现场制备了金属卟啉复合膜,对其进行SEM和ATR FTIR表征。修饰电极的支持电解质以及pH值对膜的稳定性和灵敏度有很大影响。铜卟啉 L Cys膜对H2O2具有良好的电催化还原特性,催化电流与H2O2浓度在1 0×10 6到3 0×10 5mol·L 1范围内线性关系,相关系数0 9995,检测限达1 0×10 7mol·L 1。 相似文献
68.
69.
Indr Aleknavi
ien Martynas Talaikis Rima Budvytyte Gintaras Valincius 《Molecules (Basel, Switzerland)》2021,26(22)
Tethered bilayer lipid membranes (tBLMs) have been known as stable and versatile experimental platforms for protein–membrane interaction studies. In this work, the assembly of functional tBLMs on silver substrates and the effect of the molecular chain-length of backfiller molecules on their properties were investigated. The following backfillers 3-mercapto-1-propanol (3M1P), 4-mercapto-1-butanol (4M1B), 6-mercapto-1-hexanol (6M1H), and 9-mercapto-1-nonanol (9M1N) mixed with the molecular anchor WC14 (20-tetradecyloxy-3,6,9,12,15,18,22 heptaoxahexatricontane-1-thiol) were used to form self-assembled monolayers (SAMs) on silver, which influenced a fusion of multilamellar vesicles and the formation of tBLMs. Spectroscopic analysis by SERS and RAIRS has shown that by using different-length backfiller molecules, it is possible to control WC14 anchor molecules orientation on the surface. An introduction of increasingly longer surface backfillers in the mixed SAM may be related to the increasing SAMs molecular order and more vertical orientation of WC14 at both the hydrophilic ethylenoxide segment and the hydrophobic lipid bilayer anchoring alkane chains. Since no clustering of WC14 alkane chains, which is deleterious for tBLM integrity, was observed on dry samples, the suitability of mixed-component SAMs for subsequent tBLM formation was further interrogated by electrochemical impedance spectroscopy (EIS). EIS showed the arrangement of well-insulating tBLMs if 3M1P was used as a backfiller. An increase in the length of the backfiller led to increased defectiveness of tBLMs. Despite variable defectiveness, all tBLMs responded to the pore-forming cholesterol-dependent cytolysin, vaginolysin in a manner consistent with the functional reconstitution of the toxin into phospholipid bilayer. This experiment demonstrates the biological relevance of tBLMs assembled on silver surfaces and indicates their utility as biosensing elements for the detection of pore-forming toxins in liquid samples. 相似文献
70.
为了从多源异构的复杂土地基础数据中快速准确地提取用户所需信息,提出了基于元数据的一体化管理检索方法.在元数据信息提取、元数据加权索引、实体同义词扩展检索3个环节中,结合土地领域专业知识和用户实际需求,设计和开发了共享元数据表结构、加权元数据中字段相对重要性和信息熵因子,构建地名实体和专题数据层实体同义词库,并集成到包括中文分词、实体识别、同义词扩展、索引检索和相似度计算的一体化管理检索框架中,解决了多源异构土地基础数据统一管理和精确检索的问题.实践表明,该方法较传统的通用信息检索方法具有更好的适用性和更高的准确率. 相似文献