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Proton concentration of simple binary metaphosphate glasses under a pseudo fuel cell anode reaction was investigated at 350 °C by utilizing an in-situ Fourier transform infrared (FTIR) spectroscopy. Proton concentrations of both MO·P2O5 (M = Ca, Sr) glasses increase under humidified hydrogen atmosphere and applying a direct current voltage between platinum electrodes, suggesting that a proton infiltration occurs into these glasses. Compared with CaO·P2O5 glass, SrO·P2O5 glass shows higher proton concentration at the same period of time. Structure of glass network was investigated using synchrotron radiation X-ray diffraction, 31P magic-angle spinning nuclear magnetic resonance (MAS NMR) and FTIR (KBr method) spectroscopies. Strength of the cross-linking between phosphate chains via M2+ metal cations is correlated for the proton infiltration into phosphate glasses.

This paper reports the relationship between the H2 chemisorption properties and reversible structural reorientation of the possible active sites around Al formed in situ within polymer-derived ceramics (PDCs) based on an amorphous silicon–aluminum–nitrogen (Si–Al–N) system. Al-modified polysilazane, as a ceramic precursor, was first pyrolyzed at 1000 °C under flowing ammonia to generate a Si–Al–N-based ceramic. XRD and HRTEM analyses confirmed the amorphous state of the titled ceramics. N2 adsorption–desorption isotherm measurements and HAADF-STEM observation of amorphous SiAlN indicated that Al-incorporation in the early step of the process led to the generation of micro/mesoporosity in the amorphous ceramic with nanopores of 1 to 4 nm in size. XPS and pyridine sorption infra-red spectroscopy analyses revealed the in situ formation of Lewis acidic Al sites within the amorphous Si–Al–N surface network. As a result, the Si–Al–N compound was highly moisture sensitive. Then, to investigate the intrinsic properties of the highly reactive Al sites, the Si–Al–N compound was pretreated at 400–800 °C under an inert atmosphere. Temperature-programmed-desorption (TPD)-mass spectroscopy analysis of the pre-treated sample after H2 treatment above 100 °C resulted in the detection of a broad H2 desorption peak at around 100 to 350 °C. The H2 desorption peak intensity apparently increased when H2 treatment was performed at 150 °C, and the activation energy for H2 desorption was determined to be 44 kJ mol−1. 27Al MAS NMR spectroscopic analysis for the pre-treated sample showed reversible local structure reorientation around reactive Al nuclei, and formation and deformation of 5-fold coordinated Al by H2 chemisorption and desorption, respectively. In addition, the CO2 hydrogenation reaction on the pre-treated sample was successfully demonstrated by TPD measurements after exposure to a mixed gas of H2 and CO2 with a 4 : 1 ratio at 400 °C. These results suggest that highly distorted 4-fold coordinated Al serves as a Lewis acid–base Al–N pair site to promote H2 chemisorption at T > 100 °C followed by formation of a hydrogenated 5-coordinated Al unit where CO2 hydrogenation proceeds at T = 400 °C.

This paper reports on a unique reversible reducing and oxidizing (redox) property of Co(III) in Co-doped amorphous SiO2/&gamma, Al2O3 composites. The Fenton reaction during the H2O2-catalyzed sol&ndash, gel synthesis utilized in this study lead to the partial formation of Co(III) in addition to Co(II) within the composites. High-resolution transmission electron microscopy (HRTEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analyses for the composite powder sample with a composition of Al:Si:Co = 85:10:5 showed the amorphous state of the Co-doped SiO2 that modified &gamma, Al2O3 nanocrystalline surfaces. In situ X-ray absorption fine structure (XAFS) spectroscopic analysis suggested reversible redox reactions of Co species in the composite powder sample during heat-treatment under H2 at 500 &deg, C followed by subsequent cooling to RT under Ar. Further analyses by in situ IR spectroscopy combined with cyclic temperature programmed reduction/desorption (TPR/TPD) measurements and X-ray photoelectron spectroscopic (XPS) analysis revealed that the alternating Co(III)/(II) redox reactions were associated with OH formation (hydrogenation)-deformation (dehydrogenation) of the amorphous aluminosilicate matrix formed in situ at the SiO2/&gamma, Al2O3 hetero interface, and the redox reactions were governed by the H2 partial pressure at 250&ndash, 500 &deg, C. As a result, a supported mesoporous &gamma, Al2O3/Co-doped amorphous SiO2/mesoporous &gamma, Al2O3 three-layered composite membrane exhibited an H2-triggered chemical valve property: mesopores under H2 flow (open) and micropores under He flow (closure) at 300&ndash, C.

Ag+ ion conducting xAg2O·(30 − x)Al2O3·55P2O5·15SiO2 (x = 20 and 25, mol%) glasses were prepared using a conventional melting method, and structures and glass transition temperature were investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC), ultraviolet-visible (UV–Vis) and Fourier transform infrared (FTIR) spectroscopies. Impedance measurement reveals the glass with x = 25 shows a high Ag+ ion conductivity of 3 × 10−3 S cm−1 at 300 °C. Ag+ ion emission measurement was carried out using a sharpened glass fiber tip less than 1 μm, and the emission current was successfully observed above the acceleration voltage of 4 kV at 300 °C and 4 × 10−5 Pa. Silver particles were confirmed on the target substrate after the Ag+ emission measurement. A good linear correlation is obtained between log(current) and square root of the voltage, suggesting the emission of Ag+ ion from the tip of glass fiber is expressed by Schottky model. In this ion emission method, a plasma is not required for ionization and the ion emission mechanism is simple, and various ion conducting glasses can be applied for the emitter of ion gun.

In the final exhaust chimney of oil refinery plants, new refractory materials based on geopolymers that have high resistivity to hot sulfuric acid solution, and thus long life-times, are in high demand. In order to investigate the resistance to hot sulfuric acid, a hardened cylindrical fly-ash-based geopolymer paste product (15-mm diameter, 40-mm height) with an average compressive strength of 24 MPa was placed into a Teflon vessel filled with 1.0-M sulfuric acid solution. After heating at 60–220 °C for a fixed duration, the microstructure and compressive strength characteristics were investigated. The geopolymer paste product had no damage after treatment with hot sulfuric acid at various temperatures, although hardened ordinary Portland cement bodies swelled and surface parts broke away after exposure to the same sulfuric acid solution. After the geopolymer paste product was immersed in sulfuric acid at 180 °C for 192 h, the average compressive strength was 25 MPa. With hot sulfuric acid solution treatment, natroalunite (NaAl 3 (SO 4 ) 2 (OH) 6 ) formed inside the geopolymer product as a novel crystal phase, which led to an increase in compressive strength by the accompanying densification. The fly-ash-based geopolymer paste product is a candidate material for chimney refractories of oil refinery plants.

To date, there have been few reports of the fabrication of hardened, pure calcium carbonate specimens beginning from the powder state. In this study, hardened calcium carbonate bodies exhibiting high densities and compressive strengths were produced using a warm press method. The warm press conditions consisted of temperatures from 150 to 280 °C and a uniaxial pressure of 240 MPa, applied for durations of 10–180 min to powder compacts composed of pure calcium carbonate powder or powder mixed with 10% water (by mass). Heating at 150 °C and 240 MPa for 180 min with 10% water generated a relative density of 87% and an average compressive strength of 40 MPa. The added water was found to play an important role to promote a solution-precipitation process inside the calcium powder compact, allowing low temperature sintering to form dense calcium carbonate.

Silsesquioxane (SQ) derivatives possessing intramolecular H2C = CH- groups and Si-H groups were designed as precursors for ternary silicon oxycarbide (SiOC). By using R-Si(OMe)3, H-Si(OEt)3 and (H-Si(Me)2)2O as starting compounds, SQ derivatives of VH-SQ (R = vinyl) and St-H-SQ (R = stylyl) were successfully synthesized through the conventional sol-gel route. Simultaneous thermogravimetric and mass spectroscopic analyses up to 1000 &deg, C revealed that in situ cross-linking via hydrosilylation and demethanation of VH-SQ suppressed the evolution of gaseous hydrocarbon species to afford amorphous SiOC having a composition close to the desired stoichiometric SiO2(1&minus, x)Cx (x = ca. 0.3) with a high yield. The effect of carbon content on the phase separation and crystallization of the SQ-derived amorphous SiOC was studied by several spectroscopic analyses and TEM observation. The results were discussed aiming to develop a novel polymer-derived ceramics (PDCs) route for in situ formation of binary &beta, SiC-amorphous SiO2 nanocomposites with enhanced thermal and mechanical stability.

So far dense calcium hydroxide body (slaked lime plaster) with high mechanical strength has not been fabricated yet. In this study, novel method was tried in order to fabricate the dense calcium hydroxide body. As a result, a calcium hydroxide body with a dense and high mechanical strength was obtained. Pure calcium hydroxide powder was placed in a cylindrical steel mold 15 mm in diameter, and then simultaneously pressed uniaxially at 60–240 MPa and heated to 100–250 °C for various lengths of time. This compacting process is referred to as a warm press. After warm pressing, hardened compacts composed of pure calcium hydroxide were obtained. Increasing both the applied uniaxial pressure and the heating temperature increased the compressive strength of the resulting hardened compacts. Furthermore, increasing the time spent in warm press conditions also increased the compressive strength of the hardened compacts. However, these increases diminished over time, and the compressive strength reached a nearly constant value after approximately 90 min. When the uniaxial pressure, heating temperature, and duration were 240 MPa, 250 °C and 90 min, respectively, the compressive strength of the resulting hardened compact was 57 MPa. Finally, in this study, the phase stability relationship between calcium hydroxide and calcium carbonate is discussed on the basis of chemical thermodynamics. This warm press technique for the fabrication of dense hydroxide ceramics should help clarify the formation mechanism of natural hydroxide minerals.

F− ion conducting 60ZrF4·30BaF2·LaF3·2AlF3·7CsF (mol%) with outer mol% of xIn2O3 (x = 0, 5, 10) glasses were prepared using a conventional melting method, and structure and glass transition behavior were investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Raman spectroscopy. Impedance measurement reveals the glass with x = 10 shows F− ion conductivity of 5 × 10−6 S/cm at 200 °C. F− ion emission measurement was carried out for the first time using a sharpened glass tip, and the emission current was observed above the acceleration voltage of 2.5 kV at 200 °C and 1 × 10−4 Pa. After the F− emission measurement, fluorine was detected on a Cu target substrate by using an energy-dispersive X-ray spectrometer. However, a small amount of glass component was also detected on the target substrate, suggesting the glass tip may also decompose. A good linear correlation is obtained between log(current) and the square root of the voltage, suggesting the emission current of F− ion from the tip of glass is expressed by Schottky model.

Excellent hydrophobicity of polycarbosilane (PCS)-derived Si–C–H organic-inorganic hybrid was characterized by measuring water vapor adsorption-desorption isotherms at room temperature. Modification with the PCS-derived Si–C–H successfully improved hydrostability in terms of stable gas permeation property of sol gel-derived hydrophilic mesoporous γ-Al2O3 membrane formed on a macroporous α-Al2O3 support: even under saturated water vapor partial pressure at 50 °C, the modified membrane exhibited high gas permeances of helium, hydrogen and nitrogen ranging from 1.2 to 3.0 × 10−6 mol m−2 s−1·Pa−1. The improved gas permeability under the humid condition achieved for the Si–C–H-modified mesoporous γ-Al2O3 membrane in this study was discussed aiming to prepare a gas permeable hydrophobic mesoporous intermediate layer essential for developing H2-permselective ceramic-based multilayered composite membranes with applications to novel solar hydrogen production system.

Polyalkoxysilsesquiazanes ([ROSi(NH)1.5]n, ROSZ, R = Et, nPr, iPr, nBu, sBu, nHex, sHex, cHex, decahydronaphthyl (DHNp)) were synthesized by ammonolysis at −78 °C of alkoxytrichlorosilane (ROSiCl3), which was isolated by distillation as a reaction product of SiCl4 and ROH. The simultaneous thermogravimetric and mass spectrometry analyses of the ROSZs under helium revealed a common decomposition reaction, the cleavage of the oxygen–carbon bond of the RO group to evolve alkene as a main gaseous species formed in-situ, leading to the formation of microporous amorphous Si–O–N at 550 °C to 800 °C. The microporosity in terms of the peak of the pore size distribution curve located within the micropore size range (

Perhydropolysilazane (PHPS) was chemically modified with various alcohols (ROH, R CH 3 , n-C 3 H 7 , n-C 5 H 11 , n-C 10 H 21, CH 3 OC 2 H 4 or C 2 H 5 OC 2 H 4 ) at a PHPS (Si basis) to ROH molar ratio of 3:1. The resulting alkoxy group-functionalized PHPS materials were successfully converted to amorphous silica-based inorganic-organic hybrids by exposure to vapour from aqueous ammonia at room temperature. Nitrogen sorption analyses demonstrated that these hybrids contained a small quantity of micropores less than 0.9 nm in size along with mesopores having a relatively wide pore size distribution (PSD). The PSD plots of the CH 3 O, CH 3 OC 2 H 4 O and C 2 H 5 OC 2 H 4 O functionalized samples had especially wide distributions extending to more than 50 nm. Water sorption tests showed that the hybrid synthesized from PHPS modified with n-C 10 H 21 OH was stable and did not exhibit significant capillary condensation even at higher levels of humidity above P/P o = 0.6. As a result, the number of water molecules adsorbed per square nanometre of the sample surface area at P/P o = 0.95 was as low as 4 mol nm −2 . The relatively low density of hydrophilic silanol groups (0.21), smaller average mesopore size (3.3 nm) and longer hydrophobic alkyl chain of the n-C 10 H 21 O moiety were all thought to contribute to improving the hydrophobicity of this hybrid. These results indicate that n-C 10 H 21 OH is a useful alcohol modifier for synthesizing amorphous silica-based inorganic-organic hybrid materials with improved hydrophobic properties through a polymer precursor route.

A novel polyethoxysilsesquiazane ([EtOSi(NH)1.5]n, EtOSZ) was synthesized by ammonolysis at −78 °C of ethoxytrichlorosilane (EtOSiCl3), which was isolated by distillation as a reaction product of SiCl4 and EtOH. Attenuated total reflection-infra red (ATR-IR), 13C-, and 29Si-nuclear magnetic resonance (NMR) spectroscopic analyses of the ammonolysis product resulted in the detection of Si–NH–Si linkage and EtO group. The simultaneous thermogravimetric and mass spectrometry analyses of the EtOSZ under helium revealed cleavage of oxygen-carbon bond of the EtO group to evolve ethylene as a main gaseous species formed in-situ, which lead to the formation at 800 °C of quaternary amorphous Si–C–N with an extremely low carbon content (1.1 wt %) when compared to the theoretical EtOSZ (25.1 wt %). Subsequent heat treatment up to 1400 °C in N2 lead to the formation of X-ray amorphous ternary Si–O–N. Further heating to 1600 °C in N2 promoted crystallization and phase partitioning to afford Si2N2O nanocrystallites identified by the XRD and TEM analyses. The thermal stability up to 1400 °C of the amorphous state achieved for the ternary Si-O-N was further studied by chemical composition analysis, as well as X-ray photoelectron spectroscopy (XPS) and 29Si-NMR spectroscopic analyses, and the results were discussed aiming to develop a novel polymeric precursor for ternary amorphous Si–O–N ceramics with an enhanced thermal stability.

An oxygen-excess-type lanthanum silicate (LSO) solid electrolyte with high chemical stability as well as high ion conductivity was developed by optimizing the chemical composition, La 9.333 + x (Si 6 − y Al y )O 26 + 1.5 x − 0.5 y . It was found that La 10 (Si 5.8 Al 0.2 )O 26.9 ( x = 0.667, y = 0.2) exhibited the highest conductivity among them, and addition of a small amount of iron was effective for the improvement of its chemical stability. The LSO specimen of x = 0.667 and y = 0.2 with iron addition (0.5 mol%) was chemically stable and had a conductivity of 5.6 × 10 − 2 S cm − 1 under air at 1073 K, while its electronic conductivity was less than 2.0 × 10 − 4 S cm − 1 at the same temperature. The oxygen tracer diffusion coefficient, D O * of this material was determined as 2.0 × 10 − 8 cm 2 s − 1 at 1073 K.

Binary x MO·(100 − x )P 2 O 5 (mol%; M = Ca, Mg) glasses were prepared using a conventional melting method, and the proton conduction mechanism in the glasses was investigated. The proton conductivities of the glasses were measured under various hydrogen (H 2 ) gas concentrations from 0 to 100 vol.% using Pt electrodes. The CaO·P 2 O 5 glasses show higher proton conductivities than MgO·P 2 O 5 ones. Fourier-transform infrared (FTIR) measurements showed that protons dissociated from H 2 gas at the Pt electrodes are incorporated into the glasses, and the proton conductivity increases as a result of an increase in the carrier (proton) concentration. There is a good linear relationship between the peak wavenumber of P O nb (O nb indicates non-bridging oxygen) and the proton conductivity measured in a 100 vol.% H 2 atmosphere. Furthermore synchrotron radiation X-ray diffraction (SRXRD) and FTIR results suggest that the π-electron of P O double bond is localized significantly in MgO·P 2 O 5 compared with CaO·P 2 O 5 glasses, which is the origin of higher proton conductivity in CaO·P 2 O 5 glasses.

International audience; Ionic conductivities measured under GPa-order high pressure provide various information about ion hopping mechanisms such as the activation volume (ΔV). Traditionally, anvil cells have been used for high-pressure measurements. We previously reported a new method for high-pressure impedance measurements, up to a few GPa, employing an indentation-induced local stress field. In this method, both mechanical and electrical (Young's modulus and high pressure impedance) properties can be obtained simultaneously. However, in this method, high pressures are induced only around the tip of the indenter, and such stress distribution should be considered for the estimation of ΔV accurately. In the present study, employing a finite element method (FEM) calculation, the stress distribution around the tip of the indenter, and effects of such GPa-order high pressures on the O2− ion conduction of Y2O3-doped zirconia (YSZ) are shown.

The multilayered thin film fuel cells (multilayered-TFFCs) using anatase TiO2 as an anodic catalyst were successfully prepared by layer-by-layer (LbL) assembly technique. The electrode-membrane assembly (MEA) of the multilayered-TFFC, which had a total thickness of approximately 720 nm, was constructed on a continuously porous glass substrate. The anode and the cathode were separated by the multilayered polymer electrolyte having a thickness of about 350 nm. The amounts of anodic TiO2 nanoparticles and cathodic Pt nanoparticles were calculated to be 6.2 μg cm− 2 and 18 μg cm− 2, respectively. The open circuit voltage was obtained by ultraviolet (UV) irradiation and methanol supply, because electrons were derived from photocurrent and methanol oxidation. The resultant current densities increased with increasing methanol concentration and intensity of UV irradiation. The multilayered-TFFC with 5 mol L− 1 methanol solution showed the maximum power density of 13 μW cm− 2 by UV irradiation of 20 mW cm− 2.

An asymmetric silica membrane supported on a porous alumina tube substrate was prepared by dip-coating and then surface modification multistage assembly synthesis. The mesoporous silica membrane was repeatedly modified with hexamethyldisilazane after dip-coating in silica sol solution. The separation layer of the silica membrane had an average thickness of 2 μm, mean pore radius of 1.16 nm, and BET surface area of 225 m 2 ·g − 1 . In the presence of 1 wt.% acetic acid, the membrane effectively removed ethanol and acetone from 5 wt.% organic/water binary system, or 5.0 wt.% organic–94.0 wt.% water ternary feeds by pervaporation (PV) over a temperature range of 303–323 K. The separation factor (α) of ethanol at 303 K was about 8.7, while that of acetone was 28.4. The total permeate fluxes at 303 K were 0.92 and 1.15 kg ·m − 2 ·h − 1 for ethanol/water and acetone/water feed solution, respectively. Furthermore, the separation mechanism is discussed on the basis of the relationship between the electronegativity of the feed solution composition and electronic structure of silane coupling modifier.

Electronic as well as ionic conducting properties for oxyapatite-type solid electrolytes based on lanthanum silicate, La9.333 + xSi6O26 + 1.5x (LSO) were investigated in the oxygen-excess region (x > ca. 0.3). We have found that the oxygen excess-type LSO (OE-LSO), namely La10Si6O27 on weighted basis, exhibited high conductivity, and substitution of the Si-site of LSO with some dopants (Mn+) had a positive effect toward the conducting property. Furthermore, it was also found that addition of a very small amount of iron ions into the M-doped OE-LSO, La10(Si6-yMn+y)O27-(2–0.5n)y, improved its conductivity. On the other hand, replacement of the La-site with various ions for La10(Si6-yMn+y)O27-(2–0.5n)y did little to improve conductivity. The electronic transport numbers for Al-doped OE-LSO with Fe-addition, (1-α){La10(Si5.8Al0.2)O26.9}-α(FeOγ), evaluated with the Hebb–Wagner polarization method were very low: i.e., 1.1 × 10− 3 and 2.9 × 10− 3 under P(O2) = 1.1 × 104 Pa at 1073 K for α = 0.00 and 0.005, respectively. Conductivity for each sample was unchanged under humidified atmosphere at 1073 K sustained for over 50 h, revealing that both compositions were chemically stable. It was concluded that 0.995{La10(Si5.8Al0.2)O26.9}–0.005(FeOγ) is suitable for the fuel cell electrolytes because of its high and almost pure ionic conductivity, and its good chemical stability under humidified as well as reducing conditions.

Influences on electrical property and phase relationship of oxyapatite-type solid electrolytes based on lanthanum silicate (LSO) were investigated by addition of a small amount of transition metal elements. It was revealed that a very small amount of 3d-transition metal additives into the La-excess-type, i.e., oxygen-excess-type Al-doped LSO, La10(Si5.8Al0.2)O26.9, changed its electrical conductivity. Some metals such as iron and chromium showed a positive effect for an increase in conductivity. The specimen with a nominal composition of 0.995{La10(Si5.8Al0.2)O26.9}–0.005(FeOγ), showed the maximum electrical conductivity among the specimens measured in this study. Formed phases of oxygen-excess-type Al-doped LSO based materials were found to be altered even by addition of a small amount of transition metal oxides. La-rich impurity phases such as La(OH)3 and La2SiO5 are usually detected in the oxygen-excess-type LSO, whereas no formation of La-rich impurity phases was confirmed in the case of iron addition. These results suggest that the enhancement of electrical conductivity by iron addition is due to a disappearance of the La-rich impurity phases as insulators and/or an increase in the concentration of oxygen interstitial carriers within the LSO phase.

Polyphenylsilsesquioxane (PhSiO3/2) particles as an organic-inorganic hybrid were prepared using sol-gel method, and monolithic samples were obtained via a warm-pressing. The reaction mechanism of particles’ polymerization and transformation to the monolith under the warm-press were investigated using solid state 29Si nuclear magnetic resonance (NMR) spectrometer, thermal gravimetric-differential thermal analyzer (TG-DTA), mass spectrometer (MS) and scanning electron microscope (SEM). Transparent and void-free monoliths are successfully obtained by warm-pressing above 180 °C. Both the terminal –OH groups on particles’ surface and warm-pressing are necessary for preparation of void-free PhSiO3/2 monolith. From the load-displacement measurement at various temperatures, a viscoelastic deformation is seen for PhSiO3/2 monolith with voids. On the other hand, an elastic deformation is seen for void-free PhSiO3/2 monolith, and the void-free monolith shows much higher breakdown voltage.

A typical solid acid of CsHSO 4 and phosphotungstic acid (H 3 PW 12 O 40 6H 2 O: WPA6H 2 O) were mechanically milled, and non-humidified proton conductivity of the obtained composite was investigated. The 90CsHSO 4 10WPA (mol%) composite showed high proton conductivities of 10 − 2 –10 − 4 S/cm from 160 to 30 °C under dry nitrogen atmosphere, while the conductivity of pure CsHSO 4 dropped abruptly at around 145 °C due to the phase transition from superprotonic CsHSO 4 (I) phase to CsHSO 4 (II) phase. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy measurements were performed at various temperatures to study the phase transition behaviour as well as hydrogen bonding structure. The phase transition was not observed for the 90CsHSO 4 10WPA composite. FTIR measurements revealed that a peak for OH stretching shifted to a higher wavenumber with increasing temperature. The O–H•••O hydrogen bond distance was calculated from the OH band wavenumber. The proton conductivities in dry conditions were related to the bonding distance.

Ultrathin layers of positively charged poly(diallyldimethylammonium chloride) (PDDA) and negatively charged poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) were alternately deposited on the negatively charged phenylsilsesquioxane (PhSiO 3/2 ) particles via Layer-by-Layer (LbL) technique. PDDA/PAMPS multilayer-deposited PhSiO 3/2 particles once soften and glued together with plastic deformation at temperatures higher than the glass transition temperature. Sheet-like electrolytes prepared using multilayered PDDA/PAMPS-deposited PhSiO 3/2 particles showed proton conductivities 4–6 orders of magnitude higher than those of the samples without multilayers, and the proton conductivity reached about 10 − 3 S/cm at 80 °C and 80% relative humidity.

Nafion ultrathin layers were deposited on a glass substrate by using layer-by-layer assembly technique, and proton conductivity of the multilayers was investigated. Two different types of polycations, poly(diallyldimethylammonium chloride) (PDDA) and poly(allylamine hydrochloride) (PAH) were used for the deposition of anionic Nafion layers. The incremental film growth of multilayers was monitored using a quartz crystal microbalance (QCM). QCM results revealed that the polycation and Nafion layers were deposited regularly and homogeneously. The thicknesses of one Nafion layer were estimated to be 1.5 and 10 nm for (PDDA/Nafion) n and (PAH/Nafion) n multilayers, respectively ( n means the number of layer). In the case of PDDA/Nafion multilayer, proton conductivity decreased significantly with increasing the number of layer n . On the other hand, no significant decreases in proton conductivity were observed for the PAH/Nafion multilayer. The weights of absorbed water for ultrathin multilayers were also measured and the results revealed that the formation of ionic pair of –SO 3 − ⋯N + – affects both the water uptake and proton conductivity.

On the basis of experimental data on the piezoelectric pinpoint composition of ceramics of the ternary system Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 (PMNZT), which we investigated in our previous report, epitaxial PbMg0.047Nb0.095Zr0.416Ti0.442O3 thick films with thicknesses ranging from 0.4 to 1.9 m were fabricated on Pt(100)/MgO(100) substrates by metalorganic decomposition. The film- thickness dependence on the structural and electrical properties (dielectric, piezoelectric and ferroelectric properties) was investigated. All PMNZT films exhibited a highly uniform (001) orientation, regardless of the film thickness. The cross-sectional transmission electron microscope micrographs and all the physical data suggest that high-density PMNZT thick films with a thickness  1.0 m can be expected to function as highly electrically insulating capacitors with high potential for piezo- and ferroelectric applications.

After depositing amorphous (Bi0.5La0.5)(Ni0.5Ti0.5)O3 (BLNT) films on BLNT seed layer/Pt(100)/ MgO(100) substrates by room-temperature sputtering, the crystallization of the perovskite-struc- tured films has been tried by hot isostatic pressing (HIP). The samples with a single-phase perovskite structure HIP-treated at 800°C for 1 h under gas pressures of 0.51.0 MPa showed good crystallinity of  = 0.960.98 without accompanying the precipitation of the secondary phase. It was confirmed that a large root mean square roughness value of 44.2 nm for the sample HIP-treated at 800°C for 1 h under gas pressure of 0.1 MPa is due to innumerable Bi4Ti3O12-like rod-shaped grains precipitated in the film surface, based on atomic force microscopy. It is shown that the BLNT sample HIP-treated at 800°C for 1 h under gas pressure of 1.0 MPa exhibits the best hysteresis loop shape with a remanent polarization of Pr = 5 C/cm2 and a coercive field of Ec = 150 kV/cm of the six.

Titanate nanosheet thick films were prepared on indium-tin oxide (ITO)-coated glass substrates by electrophoretic deposition. Three types of sols with different preparation procedures and pH values were prepared. In the case of titanate nanosheet films prepared from a sol with pH=7.0, surface of the films was flat and nanosheets which deposited on substrates were uniformly dense. Titanate nanosheet thick film deposited from the sol using dimethyl ethanol amine for the exfoliation showed a high photocatalytic activity due to the high crystallinity

A flip-flop-type hydrophobic coating film consisting of oppositely charged poly(allylamine hydrochloride) (PAH) and a perfluorosulfonate ionomer (Nation) ultrathin layers was prepared via layer-by-layer (LbL) assembly. The thickness of a Nafion layer was estimated to be 6.7 nm from the amount of deposited Nafion. The PAH/Nafion multilayers are optically transparent in UV-Vis region from 300 to 800 nm, and extremely small amount of Nafion was used for the coating (approximately 1.1 microg/cm2). The contact angle for water droplet of the PAH/Nafion multilayers was approximately 105 degrees. On the other hand, the contact angle for water droplet decreased rapidly from 105 degrees to approximately 85 degrees after being kept in closed vessel (approximately 100% of relative humidity) for 90 min. (approximatley 100% of relative humidity) for 15 h. The PAH/Nafion multilayer again showed hydrophobicity with the contact angle of 102 degrees after being dried at 125 degrees C for 30 min. PAH/Nafion multilayers obtained are hydrophobic in air and hydrophilic in water, namely flip-flop-type amphiphilic coating films.

An inorganic–organic hybrid of phenylsilsesquioxane-silica (PhSiO 3/2 –SiO 2 ) nanoparticle was prepared by sol–gel process, and a high proton-conducting electrolyte was synthesized by surface-sulfonation of phenyl groups of the particles. Chlorosulfonic acid was used as a sulfonation agent. The PhSiO 3/2 –SiO 2 particles are chemically stable as well as flexible. The proton conductivity of the pelletized sample reached about 10 − 2 S/cm at 80 °C and 80% relative humidity (RH). The open circuit voltage (OCV) of the single cell prepared using the pelletized sample as an electrolyte for a H 2 -air fuel cell increased with increasing the RH of the cell. The maximum power density of ~ 40 mW/cm 2 and OCV of 0.9 V was obtained at 80 °C and 95% RH.

Cesium salts of Cs 2 SO 4 , Cs 2 CO 3 and CsHSO 4 and phosphotungstic acid (H 3 PW 12 O 40 ·6H 2 O:WPA·6H 2 O) were mechanically milled to synthesize chemically durable WPA composites. The X-ray diffraction patterns of composites suggested the formation of partially substituted Cs x H 3 − x PW 12 O 40 composites after milling at 720 rpm for 10 min. Proton conductivities under both humidified and dry conditions of the resultant composites markedly improved. The proton conductivities strongly depended on the type of cesium salt. The hydrogen bonding distance L in the frame structures of the composites was estimated from the 1 H-isotropic chemical shift. The proton conductivities in dry conditions of WPA·6H 2 O and the composites were strongly represented to L .

Solid-state potentiometric thin film hydrogen gas sensors were successfully fabricated using a sol-gel-derived high proton-conducting P2O5-SiO2 glass films. Manganese oxide thin film coated on an indium tin oxide (ITO)-coated glass substrate was used for reference electrode. The sensor exhibited high speed responsibility within 10 s and 120 s at 30 oC and -30oC, respectively, for 1 vol.% hydrogen gas. A linear relationship between the electromotive force (EMF) and the logarithmic hydrogen concentration of 0.1~1 vol.% was obtained in the temperature ranging from -30 to 30 oC. The sensing mechanism was also discussed to improve the sensitivity and sensing speed against low H2 concentration at low temperatures.

Thermally and chemically stable phenylsilsesquioxane (PhSiO 3/2 ) particles were prepared by sol–gel process, and ultra-thin layers of oppositely charged poly(diallyldimethylammonium chloride) (PDDA) and dodecatungstophosphoric acid (WPA) were alternately deposited on the negative-charged PhSiO 3/2 particles via layer-by-layer assembly technique. Hygroscopic property of WPA was remarkably reduced owing to the formation of PDDA/WPA complex. The amount of WPA adsorbed on PhSiO 3/2 particles was estimated to be ∼ 0.03 (g/g PhSiO 3/2 ). Transparent and monolithic pellet can be obtained from the resultant core–shell particles by pressing. Proton conductivity of WPA-deposited samples increased about 4 orders of magnitude compared with unmodified samples, and reached to about 10 − 4 S/cm at 80 °C and 80% relative humidity.

Thermally and chemically stable proton conductors were prepared via surface-sulfonation of sol–gel-derived phenylsilsesquioxane–methylsilsesquioxane (PhSiO3/2–MeSiO3/2) particles in a range from 250 to 650 nm in diameter. MeSiO3/2 component was indispensable to improve the chemical durability against sulfonation solvent. Proton conductivity of the pelletized samples prepared using the sulfonated PhSiO3/2–MeSiO3/2 particles increased linearly with increasing the ion exchange capacity (IEC) of the particles. The mobility (μ) of proton was calculated to be 0.3 × 10− 4 cm2/V s. Porous PhSiO3/2–MeSiO3/2 particles prepared using a cationic surfactant of cetyltrimethylammonium bromide (CTAB) as a template of pores showed higher both IEC and water uptake, leading to an increase in proton conductivity to ∼ 10− 2 S/cm at 80 °C and 80% relative humidity.

Cs-containing salt or solid acid (Cs2CO3 or CsHSO4) and dodecatungstophosphoric acid (H3PW12O40·nH2O:WPA·nH2O) were mechanically milled aiming at synthesis of chemically durable WPA salts and their composites. In the Cs2CO3–WPA system, XRD patterns suggested the formation of partially substituted CsxH3 − xPW12O40 after milling. After the formation of CsxH3 − xPW12O40, chemical durability of the Cs2CO3–WPA composites markedly improved. The proton conductivity of the Cs2CO3–WPA composites containing CsxH3 − xPW12O40 increased with an increase in the WPA content. CsxH3 − xPW12O40 obtained from 40Cs2CO3·60(WPA·6H2O) by milling showed 2 × 10− 2 S cm− 1 at 60 °C and 90% relative humidity (R.H.), while the conductivity drastically decreased under a dry N2 atmosphere. In the CsHSO4–WPA system, the formation of CsxH3 − xPW12O40 was not confirmed from XRD patterns after mechanical milling, whereas the water solubility of the CsHSO4–WPA composites decreased. The conductivity of 95CsHSO4·5(WPA·6H2O) with milling increased with increasing humidity and became 1 × 10− 2 S cm− 1 at 60 °C and 90% R.H. The mechanically milled 95CsHSO4·5(WPA·6H2O) composite exhibited a steep increase in conductivity at around 130 °C on heating even in a dry N2 atmosphere and the conductivity reached about 10− 3 S cm− 1 at 150 °C, which should be ascribed to the superprotonic phase transition of CsHSO4 in the composite.

Dodecatungstophosphoric acid (H 3 PW 12 O 40 · n H 2 O) and SiO 2 were mechanically milled, and a new class of proton-conductive composites was prepared. The conductivity of WPA–SiO 2 composite with P/Si = 0.1 was 3 × 10 − 3 S cm − 1 at 30 °C and 60% relative humidity (RH), which was higher than that (6 × 10 − 4 S cm − 1 ) of the corresponding mixture before milling. In the medium temperature range, the WPA–SiO 2 composite retained relatively high conductivity of 1 × 10 − 4 S cm − 1 at 100 °C and 2% RH, which was higher by one order of magnitude than that of the mixture without milling. These higher values of conductivity for the milled composite can be ascribed to the presence of mechanochemically formed surface defects such as Si–OH and P–OH groups.

Proton conductivity of ordered mesoporous phosphosilicate glass films, prepared by an interfacial self-assembly technique, was related with the water molecules absorbed in the ordered pores. The mixed solutions of hydrolyzed-alkoxides and cationic surfactant CH 3 (CH 2 ) 15 N + (CH 3 ) 3 Br − were coated on the substrates, followed by heating to remove the surfactant at 400 °C. Pore channels parallel to the substrate surface were formed by dip-coating the solution, which did not offer a pathway for proton transfer, resulting in the low conductivity of the film. The aging of the precursor solutions before coating caused the pores to orient from two- to three-dimensionally ordered structure. The water molecules absorbed in the three dimensionally connected pores acted as the pathway for proton transfer, resulting in the increased conductivity.

The proton transfer in nanopores was investigated using the sol–gel-derived porous silica glasses. The glasses with the pore size of 2–25 nm in diameter were prepared using the sol–gel method and the proton conduction through water molecules adsorbed in pores was discussed by the measurement of the conductivity, electrical modulus, and diffusion coefficient. In the porous glasses with pores larger than ∼15 nm, the pores are not filled with the water molecules, resulting into the decreased proton conduction. As the pore size decreases, the pores are filled with the physically bonded water molecules, which act to form the pass way of proton conduction. On the other hand, in the pores smaller than ∼2 nm, much of the adsorbed water is chemically bound and restricts the proton hopping. It was found that the glass having pores ∼4 nm diameter is more appropriate for the fast-proton-conducting glasses.

International audience; Electrical measurements of conducting and dielectric materials under high pressures (in the order of GPa) reveal important information regarding orbital overlaps, electronic states, changes in transition temperatures, and activation volumes (Delta V). In this study, we demonstrate a new method for high-pressure impedance measurements, up to 4 GPa, utilizing an indentation-induced local stress field. The current system does not require any pressure mediums or pressure calibrations. The Delta V for O2- ion conduction in 10 mol\% Y2O3-doped zirconia at 500 degrees C was estimated to be 3.0 cm(3) mol(-1). Delta V increased with increasing temperatures from 500 to 600 degrees C. The technique also allows the concurrent determination of the effective elastic modulus by fitting the experimental data obtained from the indentation load-depth profile curve with the Hertzian elastic model. The experimental values were consistent with the theoretical values. (C) 2013 Elsevier B.V. All rights reserved.

CsHSO 4 and dodecatungstophosphoric acid (H 3 PW 12 O 40 ·6H 2 O:WPA·6H 2 O) were mechanically milled to synthesize x CsHSO 4 ·(100 − x )WPA (mol%) composites. 1 H NMR measurements suggested that a hydrogen bond was newly developed between WPA and CsHSO 4 , and proton transfer at CsHSO 4 –WPA composite region was considered to be faster than that at pure CsHSO 4 or WPA. Proton conductivity of the 90CsHSO 4 ·10WPA (mol%) composite at 100 °C showed much higher of 3.3 × 10 − 3 S/cm than that of pure CsHSO 4 (4 × 10 − 7 S/cm) or that of WPA(1 × 10 − 7 S/cm). The –O(H)···O hydrogen bonding distance was estimated from the 1 H-isotropic chemical shift of 1 H MAS NMR spectra. The proton conductivities in dry atmosphere of CsHSO 4 ·WPA composites were strongly correlated with the O(H)···O bond distance L .