| Co-Investigator(Kenkyū-buntansha) |
IZU Noriya Osaka University, Graduate School of Engineering, Research Assistant, 大学院・工学研究科, 助手 (00304014)
OMATA Takahisa Osaka University, Graduate School of Engineering, Research Assistant, 大学院・工学研究科, 助手 (80267640)
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| Research Abstract |
Pyrochlore-type oxide La_2Zr_2O_7 doped with Ca^<2+>, Sr^<2+>, Ba^<2+> on its A and B sites, respectively, dissolves proton ; however, the reaction for the dissolution may be different on the point of positive hole depletion. In the present study, the oxides doped with Ca^<2+> on its A and B sites, respectively, annealed under the H_2O and D_2O gases, respectively, were subjected to infrared spectroscopic analysis. For the A-site displaced sample with H_2O treatment, three sharp peaks were observed around 3500 cm^<-1> ; the result was completely different from that for the perovskite-type oxides exhibiting a broad spine which are well known as proton conductor at high temperatures. When done with D_2O treatment, the peaks was shifted toward a lower wave number, i.e., 2500 cm^<-1>, keeping the shape of the peaks. It could be concluded that the spectra detected came from the dissolved proton. For the B-site displaced sample, more than 6 peaks appeared. Dependence of the spectrum strength
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on the water vapor pressure differed obviously between the A-site and B-site displacements. These results have revealed that the mechanism of the proton dissolution are different, i.e., on the point of the positive hole depletion. When the water vapor pressure of the atmosphere was changed, the difference may induce a voltage for the junction of the A-site and B-site displaced oxides. We could confirmed the junction voltage experimentally. Thus, using the mixtures of the A-site and B-site displaced oxides powders, which we call organic cell-type ceramics, we tried the NO_2 decomposition based on the internal voltage induced. An quadruple-pole mass spectrometry was used to measure the NO_2 concentration, evacuating the system ; however, the leak of the system could not be neglected. The final objective of the present works was to construct organic cell-type ceramics by mixing the powders and utilizing the internal voltage among the cell, i.e., boundary, to decompose the NO_x gas. To attain the important subject, improvement on the production way of the fine oxides powder, possibly together with platinum powder, and also the detection technique of NO_x gas have been needed. Less
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