Dye sensitized photovoltaic cells: Attaching conjugated polymers to zwitterionic ruthenium dyes

The synthesis of a zwitterionic ruthenium dye that binds to anatase surfaces and has a built-in functionality that allows for the attachment of a conjugated polymer chain is presented. The system was found to adsorb on the surface of anatase anchored by the ruthenium dye. Two types of devices were prepared: standard photoelectrochemical (PEC) solar cells and polymer solar cells. The PEC solar cells employed a sandwich geometry between TiO₂ nanoporous photoanodes and Pt counter electrodes using LiI/I₂ in CH₃CN as an electrolyte. The polymer solar cells employed planar anatase electrodes and the complex was adsorbed onto the surface before evaporation of gold electrodes. Alternative devices were obtained by spincoating of the polymer solution onto PEDOT:PSS covered indium-doped tin oxide substrates. PEC solar cells gave the best results and the main finding was that the polymer chain served as a light harvesting antenna for the ruthenium dye.     

SBS加氢动力学的研究

以三（三苯基膦）二氯化钌「ＲｕＣｌ２（ＰＰｈ３）」为催化剂,三苯基膦（ＰＰｈ３）为配体对苯乙烯－丁二烯嵌段共聚物（ＳＢＳ）加氢,在１５０℃下进行了ＳＢＳ加氢动力学研究,得到了加氢动力学方程：－ｄ「Ｃ＝Ｃ」／ｄｔ＝ｋ「ｈ２」＾１．１２「Ｃ＝Ｃ」「Ｒｕ＾＊」「ＰＰｈ３」＾－１,１３０￣１６０℃的加氢反应活化能力２２．７４ｋＪ／ｍｏｌ。     

Identification of RuO2 as the active phase in CO oxidation on oxygen-rich ruthenium surfaces

CO oxidation over ruthenium dioxide (RuO₂) dominates the CO/CO₂ conversion rate over the catalytically active oxygen-rich Ru(0001) surfaces. In sharp contrast, chemisorbed O overlayers on Ru(0001) (with and without dissolved oxygen) are virtually inactive with respect to CO oxidation.     

On the mechanism of the selective catalytic reduction of NO to N2 by H2 over Ru/MgO and Ru/Al2O3 catalysts

Steady-state and transient kinetic experiments were performed in a versatile microreactor flow set-up with magnesia- and alumina-supported ruthenium catalysts in order to elucidate the mechanism of the selective catalytic reduction (SCR) of nitric oxide with hydrogen. Both Ru/MgO and Ru/γ-Al₂O₃ were found to be highly active catalysts converting NO and H₂ into N₂ and H₂O with selectivities close to 100% at full conversion, although Ru-based catalysts are known to be active in the synthesis of NH₃ from N₂ and H₂. Frontal chromatography experiments with NO at room temperature revealed that NO and its dissociation products displace adsorbed atomic hydrogen (H−*) almost completely from hydrogen-precovered Ru surfaces. Obviously, NO and H₂ compete for the same adsorption sites, H−* being the weaker bound adsorbate. Temperature-programmed surface reaction (TPSR) experiments in H₂ subsequent to NO exposure demonstrated that higher heating rates and lower partial pressures of H₂ shift the selectivity from NH₃ to N₂. Therefore, the coverage of H−* is concluded to govern the branching ratio between the rate of associative desorption of N₂ (2N−*→N₂ + 2*) and the rate of hydrogenation of N−* (N−* + 3H–* →NH₃ + 4*). Finally, the steady-state coverages of N- and O-containing adsorbates were derived by interrupting the SCR reaction and hydrogenating the adsorbates off as NH₃ and H₂O. By solving the site balance, the Ru surfaces were found to be essentially N₂ is attributed to the very low coverage of H−* due to site blocking by a N + O coadsorbate layer, favouring the recombination of N−* instead of its hydrogenation to NH₃. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effect of support materials on the performance of direct ethanol fuel cell anode catalyst

Pt–Ru catalysts supported on mesoporous carbon nitride (MCN), multiwall carbon nano tubes (MWCNTs), treated MWCNTs (t-MWCNTS) and Vulcan-XC were prepared using co-impregnation reduction method for the oxidation of ethanol in direct ethanol fuel cell (DEFC) to study the effect of support material. The MCN support was prepared using SBA-15 as template and t-MWCNTs were prepared by refluxing in HNO₃ and H₂SO₄ mixture (1:3) using MWCNTs. XRD shows the formation of Pt–Ru bi-metallic catalyst with size ranges from 7 to 17 nm using different supports. The catalyst and its supports were characterized by physically and electrochemically. Linear sweep voltammetry, cyclic voltammetry and chrono amperometry studies of the above systems reveal that MCN supported Pt–Ru catalyst shows higher electro-catalytic activity towards ethanol oxidation compared to Pt–Ru in treated t-MWCNTs, MWCNts and Vulcan-XC supports. The performance of DEFC based on maximum power density is found to be in the order Pt–Ru/MCN > Pt–Ru/t-MWCNTs > Pt–Ru/MWCNTs > Pt–Ru/Vulcan-XC. The Pt–Ru/MCN shows highest power density of 61.1 mW cm⁻² at 100 °C, 1 bar pressure with catalyst loading of 2 mg cm⁻² using 2 M ethanol feed.     

水杨酸体系抛光液中钌的化学机械抛光研究

研究了抛光液中H2O2和水杨酸浓度对钌的抛光速率的影响。采用电化学方法和X射线光电子能谱分析了H2O2和水杨酸对金属钌腐蚀效果的影响;采用原子力显微镜观察钌表面的微观形貌。结果表明:水杨酸浓度的增加有利于金属钌表面钝化膜的形成,抛光速率值随之增加;随着H2O2浓度的不断增加,抛光速率不断增加,当H2O2质量分数大于3%时,抛光速率值随浓度的增加而降低。抛光后的金属钌表面平均粗糙度Ra为7.2 nm。     

Solid state synthesis of hydrous ruthenium oxide for supercapacitors

A novel solid state route has been successfully developed for the synthesis of nano-scale hydrous ruthenium oxide (denoted as RuO₂·xH₂O). The procedure involves directly mixing RuCl₂·xH₂O with alkali to form RuO₂·xH₂O in a mortar at room temperature. Transmission electron microscopy (TEM) and N₂ adsorption–desorption measurement indicate that the RuO₂·xH₂O particle is approximately 30–40 nm with mesoporous structure. The crystalline structure and the electrochemical properties of RuO₂·xH₂O have been systematically explored as a function of annealing temperature. At lower temperatures, the RuO₂·xH₂O powder was found in an amorphous phase and the maximum capacitance of 655 F g⁻¹ was obtained by annealing at 150 °C. Higher temperatures (exceeding 175 °C) presumably converted amorphous phase into crystalline one and the corresponding specific capacitance dropped rapidly from 547 F g⁻¹ at 175 °C to 87 F g⁻¹ at 400 °C. Also, the dependence of electrochemical performance on annealing conditions of RuO₂·xH₂O was investigated by electrical impedance spectroscopy (EIS) study.     

Electrical Properties of the Ta-RuO2 Diffusion Barrier for High-Density Memory Devices

The electrical properties of a Ta layer prepared with and without RuO₂ addition were investigated. The Ta + RuO₂/TiSi₂/poly-Si/SiO₂/Si contact system exhibited lower total resistance and ohmic characteristics up to 800°C. Meanwhile, the Ta/TiSi₂/poly-Si/SiO₂/Si contact system showed higher total resistance and nonohmic behavior after annealing at 650°C, attributed to the oxidation of both Ta and TiSi₂ layers. In the former case, a Ta + RuO₂ diffusion barrier showed an amorphous Ta microstructure and embedded RuO _x nanocrystals in the as-deposited state. The conductive RuO₂ crystalline phase in the Ta + RuO₂ film was formed by reaction between the nanocrystalline RuO _x and oxygen indiffused from air during annealing. When the Ta layer was deposited with RuO₂ addition, therefore, both the electrical properties and the oxidation resistance of the Ta + RuO₂ diffusion barrier were better than those of TiN, TaN, and Ta-Si-N barriers.     

Continuous‐Flow Asymmetric Hydrogenation of the β‐Keto Ester Methyl Propionylacetate in Ionic Liquid–Supercritical Carbon Dioxide Biphasic Systems

A continuous‐flow process for the asymmetric hydrogenation of methyl propionylacetate as a prototypical β‐keto ester in a biphasic system of ionic liquid and supercritical carbon dioxide (scCO₂) is presented. An established ruthenium/2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP) catalyst was immobilised in an imidazolium‐based ionic liquid while scCO₂ was used as mobile phase transporting reactants in and products out of the reactor. The use of acidic additives led to significantly higher reaction rates and enhanced catalyst stability albeit at slightly reduced enantioselectivity. High single pass conversions (>90%) and good enantioselectivity (80–82% ee) were achieved in the first 80 h. The initial catalyst activity was retained to 91% after 100 h and to 69% after 150 h time‐on‐stream, whereas the enantioselectivity remained practically constant during the entire process. A total turnover number of ∼21,000 and an averaged space‐time yield (STY_av) of 149 g L⁻¹ h⁻¹ were reached in a long‐term experiment. No ruthenium and phosphorus contaminants could be detected via inductively coupled plasma optical emission spectrometry (ICP‐OES) in the product stream and almost quantitative retention by the analysis of the stationary phase was confirmed. A comparison between batch‐wise and continuous‐flow operation on the basis of these data is provided.     

Ruthenium‐Catalyzed One‐Pot Tandem Isomerization–Transfer Hydrogenation Reactions of γ‐Trifluoromethylated Allylic Alcohols and β‐Trifluoromethylated Enones

The ruthenium–2‐propanol combination was found to transform γ‐trifluoromethylated allylic alcohols and β‐trifluoromethylated enones into the corresponding saturated alcohols in excellent yields via a one‐pot tandem process involving isomerization and transfer hydrogenation(s). High stereospecificity was demonstrated and evidence for two mechanistic pathways is provided. The method was applied to a rapid synthesis of trifluoromethylated citronellol.