Nano-sized SmFeO3 particles are prepared by the pyrolysis of heteronuclear cyano-complex, SmFe(CN)6·4H2O at a temperature of 600 °C in ozone. The low temperature decomposition followed in ozone ...successfully yielded fine particles with a high specific surface area of 20.0 m3/g (sample A). The fine particles were classified into further smaller particles with a unimodal size distribution and this process yielded a high specific surface area of 26.0 m3/g (sample B). These semiconducting powders were deposited on a sensor electrode by electrophoretic deposition (EPD) and tested on their sensing properties to VOCs. The sensors consisting of samples A and B both showed good responses to ethanol at 285 and 320 °C. The sensor with sample B showed extraordinarily good selectivity of ethanol for toluene at 320 °C. This could be because the detection film of sample B with moderately grown particles selectively reduced the reaction activity of toluene. The sensor with sample B also exhibited good selectivity of ethanol for hexane and dichloromethane.
A Fe-modified Na-P1 type artificial zeolite (Fe-P1) was prepared by mixing with the synthesized zeolite powder using chemical reagents and FeCl3 solution. The anion exchange capacity was generated by ...the iron hydroxyl group on the zeolite surface. Although the intensity of the X-ray diffraction (XRD) peaks for the zeolite phase decreased with an increase in the concentration of the mixed FeCl3 solution, the anion exchange ability for the phosphate was improved due to the increase in the surface area. The Fe-P1 zeolite showed a high selectivity for the anions of phosphoric acid and arsenic acid. The anion adsorption capacity was significantly increased under the acidic condition (pH 5) of the solution. Acidic treatment of the Fe-P1 zeolite was also effective for the anion adsorption.
A single material with a whitish fluorescence was found from silver exchanged zeolite Y. We obtained that material by washing zeolite Y (cation exchange capacity: 3.34 mmol/kg) with AgNO3 solutions ...followed by heat treatments. Their fluorescence spectra were composed of two peaks (peak-1: 448 nm; peak-2: 503 nm) with excitation at 230–320 nm. The fluorescence intensity of the two peaks increased up to an Ag-exchange amount of 0.5 mmol/g, but a further increase in the amount decreased the intensity of the two peaks. Heating treatments up to 500 °C increased the fluorescence intensity, especially of peak-1. Alkali metal cations coexisting with Ag in the partially Ag-exchanged zeolite Y also affected the fluorescence intensity, and the co-existence of Li+ significantly increased the intensity of a peak-1. The maximum fluorescence intensity (internal quantum yield: 41%) was observed at a 0.5 mmol/g Ag-exchange with the coexistence of 1.30 mmol/g of Li+ and 1.54 mmol/g of Na+ after heating at 500 °C.
The single phase of the chabazite (CHA) was artificially synthesized in the absence of organic-structure-directing agents and a seed crystal. The CHA showed a high selectivity of 91.2% for Cs ions in ...sea water (1.0 g CHA in 100 ppm Cs containing 100 mL sea water), which was superior to 87.1% of the synthesized mordenite. The single phase of the merlinoite (MER) was obtained by lack of a fluoride source. The Cs adsorption performance for the MER was 83.1% in the seawater. The CHA was heat-treated for the immobilization of the Cs in the decomposed zeolite. For the non-heated sample, ca. 1.2% Cs ion from all of the adsorbed Cs was eluted by a dissolution test in deionized water for 14 days. The Cs ion did not elute when the sample was heated at 1000 °C and higher temperature due to the Cs containment in the amorphous phase.
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•We Chabazite (CHA) was synthesized using chemical reagents in absence of organic-structure-directing agents and seed crystal.•The Cs selectivity in the seawater was superior for the CHA compared with those of merlinoite (MER) and mordenite (MOR).•The Cs ion did not elute when the CHA was heated at 1000 °C and higher temperature.
A ternary Ni–BaCe0.9Y0.1O3 (BCY)–Ce0.9Gd0.1O2 (GDC) cermet involving 40 vol% Ni was fabricated, and its hydrogen permeation characteristics were evaluated when the GDC volume fraction was varied from ...0 to 30 vol%. The X-ray diffraction results of the cermet after sintering at 1400 °C revealed that GDC was dissolved in BCY when the GDC volume composition was 20 vol%. Regardless of the BCY and GDC volume fractions, the metal conductivity of the cermet was dominated by Ni. After the addition of only 1 vol% GDC, the particle sizes of Ni and BCY in the cermet significantly decreased, and the particle size decreased as the volume fraction of GDC increased. The hydrogen permeability increased with increasing temperature and for up to 10 vol% GDC, and a maximum permeation rate of 0.142 mL min−1 cm−2 was obtained at 700 °C. This value is comparable to or better than previously reported values for Ni-cermets under the same conditions. The amount of hydrogen permeation decreased above 10 vol% GDC. This study demonstrated that Ni-BCY-GDC cermet is a material that has both high hydrogen permeability and CO2 resistance.
The Cs ion was partially adsorbed (4.0% in all of the alkali cation sites) on natural mordenite as a simulated decontamination, then heat-treated to immobilize the Cs in the decomposed zeolite. ...Although the mordenite phase was maintained for the samples even heated at 800 °C, a glassy amorphous phase formed due to the decomposition of the mordenite at 900 °C. In the case of the non-treated sample, 3.6% Cs ion from all of the adsorbed Cs was eluted by a dissolution test in deionized water for 14 days. The elution ratio of the Cs ion decreased by the heat treatment. The Cs ion did not elute when the sample was heated at 1000 °C and higher temperature due to the Cs containment in the glassy phase. Na2CO3 powder was mixed with the mordenite for lowing the glass-forming temperature. The mordenite mixed with Na2CO3 had a lower melting point and immobilized the Cs at 900 °C. The Cs evaporation during the heating was also depressed by the Na2CO3 addition.
The Cs ion did not elute when the Cs ion adsorbed natural mordenite was heated at 1000oC and higher temperature due to the Cs containment in the glassy phase. Display omitted
•The Cs partially adsorbed natural mordenite was heat-treated to immobilize the Cs in the decomposed zeolite.•The Cs ion did not elute when the sample was heated at 1000 °C and higher temperature.•The mordenite mixed with Na2CO3 had a lower melting point and immobilized Cs at 900 °C.
Cermet films consisting of Ni, BaCe0.4Zr0.4Y0.2O3−δ (BCZY), and Gd0.1Ce0.9Ox (GDC), specifically, 60 wt%Ni–BCZY, 60 wt%Ni–BCZY–GDC, and 60 wt%Ni–GDC, were formed on BCZY electrolyte supports as ...anodes of proton ceramic fuel cells (PCFCs). The Ni grain size in these films after sintering at 1450 °C was around 2 μm. The GDC addition did not affect the Ni grain size in the case of the BCZY matrix. The anodic properties greatly depended on the oxide phase composition and worsened with increasing the GDC content. This probably occurred because of the addition of GDC, which has low proton conductivity and inhibited the proton conduction path of BCZY, reducing three-phase boundaries in the anode bulk. Since BCZY has a lower grain growth rate during sintering than BaCe0.8Y0.2O3−δ, the Ni grain growth was likely suppressed by the surrounding Ni grains containing small BCZY grains.
Potentiometric sensors aiming at detecting H2 were examined. Yttria-stabilized zirconia (YSZ) based sensor elements, H2, Pt/YSZ/Pt, air, responded to a ppm level of H2 contamination in air with the ...value of electromotive force (ΔEMF) = 30 mV at 350 °C. Coating the Pt sensing electrode with a powder of hexagonal boron nitride (h-BN) increased the EMF response, and the sensor response further increased by the milling treatment of the h-BN powder in ethanol. However milling treatment over 24 h reversed the response to decreasing. The specific surface area of the h-BN powder monotonously increased by the ball-milling which induced exfoliation of the BN layer. While Fourier transform infrared spectroscopy analysis suggested that point defects existing in the BN plane react with ethanol or water by the milling for >48 h. It was concluded that the point defects in h-BN play a decisive role in the property of the h-BN auxiliary phase in sensor response to H2.
The effect of the lithium ion coexistence on the fluorescent properties was studied for a partially Ag-exchanged LTA (A-type) zeolite. A series of Ag–Li-LTA zeolite samples was prepared by mixing the ...LTA zeolite powder (1.0 g) with aqueous solutions (100 mL) containing AgNO3 (0.5 mmol) and various amounts of LiNO3 (0–100 mmol). Although the fluorescence intensity was hardly observed in the unheated state for the Ag-LTA and the Ag–Li-LTA zeolites, the intensity was enhanced by the heat-treatment and showed the maximum value for the samples heated at 600 °C. A dramatic enhancement in the fluorescence intensity was observed by increasing the amount of the Li addition with a heat treatment at 600 °C. The highest fluorescent intensity was reached for the Ag(2.8%)–Li(72.6%)-LTA zeolite doped using the solution containing 0.5 mmol/g AgNO3 and 100 mmol/g LiNO3. Furthermore, the fluorescence shifted from a 605 nm (yellow) to the shorter wavelength of 505 nm (green) with the increasing Li amount. The fluorescent intensity due to the coexisting lithium ion for the Ag-exchanged LTA zeolite was significantly superior to those of the Ag–Li-FAU(X- and Y-types) zeolites.
Samaria-doped ceria, (SmO1.5)0.2(CeO2)0.8 (SDC), containing nickel (Ni) was prepared as the anode of solid oxide fuel cell fueled with 6% ammonia (NH3). The Ni-free SDC powders prepared by the ...reverse co-precipitation method exhibited poor catalytic activities for NH3 decomposition in 6% NH3/Ar. Impregnation of Ni onto the SDC powders significantly enhanced its catalytic activity. The catalytic activity was highest at 10 wt % Ni–SDC, but it decreased with an increase in the Ni content. Contrary to expectation, the anodic performances were similar between 10 and 40 wt % of Ni loading and the highest maximum power densities were 98.8 and 96.5 mW·cm−2 at 900°C, respectively. Impedance analysis of the anodes revealed that the anodic performance was rate-controlled by the similar process in 4%H2 fuel and that was electrochemical oxidation and diffusion processes.
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