A layered compound composed of crystalline ruthenic acid sheets interleaved with layers of water can be exfoliated (delaminated) to yield colloidal nanosheets. This material is a mixed conductor where the crystalline nanosheets contribute to the electron conductivity and the hydrous interlayer supplies proton transport (see diagram). A large active surface area and a high specific capacitance is promising for electrochemical supercapacitor applications.

Electrochemical impedance spectroscopy was conducted on a series of hydrous ruthenium oxides, RuO(2).xH(2)O, (x = 0.5, 0.3, 0) and a layered ruthenic acid hydrate (H(0.2)RuO(2.1).nH(2)O) in order to evaluate their protonic and electronic conduction. The capacitor response frequency was observed at lower frequency for RuO(2).xH(2)O with higher water content, which was suggested to be due to electrolyte exhaustion within the film and/or utilization of hydrated interparticle micropores that have high ionic resistance. Analysis of the impedance data indicated that the charge-transfer resistance through the film is not significantly affected by the water content in RuO(2).xH(2)O, and the capacitor frequency response is dominated by the protonic conduction. The capacitor response frequency of layered H(0.2)RuO(2.1).nH(2)O was comparable to RuO(2).0.5H(2)O. The high specific capacitance at low frequency for layered H(0.2)RuO(2.1).nH(2)O is attributed to the utilization of the expandable hydrous interlayer, which accounts for the ionic conduction. The present results demonstrate the importance of hydrous regions (either interparticle or interlayer) to allow appreciable protonic conduction for high energy and high power electrochemical capacitors.

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The charge storage mechanism of nanostructured anhydrous and hydrous ruthenium-based oxides was evaluated by various electrochemical techniques (cyclic voltammety, hydrodynamic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy). The effects of various factors, such as particle size, hydrous state, and structure, on the pseudocapacitive property were characterized. The electric double layer capacitance (C dl), adsorption related charge (C ad), and the irreversible redox related charge (C irr) per unit mass and surface area of electrode material has been estimated and the role of structural water within the material either in micropores or interlayer are discussed.

Introduction. Phospholipase A 2 (PLA 2 ) is a group of lipolytic enzymes that catalyze the hydrolysis of fatty acid ester bonds at the sn-2 position of phospholipids. This enzyme is thought to play an important role in the biosynthesis of eicosanoids via the release of arachidonic acid from biomembranes. Another product from biomembranes, a lysophospholipid, is converted to plateletactivating factor (PAF) known as an inflammatory mediator. PLA 2 s have been generally classified into secretory PLA 2 (sPLA 2 ), cytosolic PLA 2 (cPLA 2 ), and Ca 2+ -independent PLA 2 (iPLA 2 ) by their molecular weights, amino acid sequences, and calcium requirements. 1 cPLA 2 comprises three distinct types of enzymes: R, β, and γ. 2 cPLA 2 R, an 85-kDa protein, contains a calcium-dependent lipid binding domain and a catalytic domain, requires micromolar levels of Ca 2+ for membrane translocation, and has a specificity for arachidonic acid bound to the sn-2 position of phospholipids 3 in contrast with sPLA 2 and iPLA 2 which have broad substrate specificities, suggesting that cPLA 2 R is involved in the production of eicosanoids.

A tetrabutylammonium-H 2 Ti 4 O 9 ?xH 2 O intercalation compound was obtained by a guest exchange reaction between tetrabutylammonium hydroxide and an ethylammonium-H 2 Ti 4 O 9 ?xH 2 O intercalation compound, and its dispersion state in aqueous and non-aqueous solutions were studied. Spontaneous exfoliation of H 2 Ti 4 O 9 ?xH 2 O into colloidal nanosheets occurred when the tetrabutylammonium-H 2 Ti 4 O 9 ?xH 2 O intercalation compound was dispersed in water, methyl alcohol, isopropyl alcohol, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, and propylene carbonate, while exfoliation did not occur in tetrahydrofuran. A tetrabutylammonium-H 2 Ti 4 O 9 ?xH 2 O film was obtained by a reassembly process by casting the colloidal suspension containing exfoliated nanosheets, while a H 2 Ti 4 O 9 ?xH 2 O film was directly obtained by electrophoretic deposition. Thermal treatment of the electrophoretically deposited film led to an oriented TiO 2 (B) film with the (0k0) planes lying perpendicular to the substrate.

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Carbon-supported binary PtRu electrocatalysts were prepared by coimpregnation using ethanolic solutions of Pt(NH 3 ) 2 (NO 2 ) 2 as the Pt source, various Ru sources [RuCl 3 , Ru 3 (CO) 12 , and RuNO(NO 3 ) x ], and carbon black by thermal decomposition under reducing conditions, and their structure, morphology, and electrocatalytic properties were investigated. X-ray diffraction analysis and high resolution scanning electron microscopy indicated that the use of Cl-free Ru sources, i.e., Ru 3 (CO) 12 or RuNO(NO 3 ) x , afforded highly dispersed and uniform PtRu nanoparticles. Surface area measurements conducted by electro-oxidation of preadsorbed carbon monoxide indicated that the use of Ru 3 (CO) 12 as the Ru source yielded high surface area catalysts. In terms of the surfacearea specific current density (current density normalized by the specific surface area of PtRu metal obtained from preadsorbed CO electro-oxidation measurements), the electrocatalytic activity of Pt(NH 3 ) 2 (NO 2 ) 2 -Ru 3 (CO) 12 and Pt(NH 3 ) 2 (NO 2 ) 2 -RuNO(NO 3 ) x were equal. PtRu/C electrocatalysts prepared from ethanolic solutions of Pt(NH 3 ) 2 (NO 2 ) 2 -Ru 3 (CO) 12 resulted in high mass-specific activity toward methanol oxidation, with mass-specific current density as high as 159 mA mg Ϫ1 Pt at 500 mV. The efficiency of PtRu/C electrodes is discussed based on the significance of the use of Cl-free Ru sources.