1997 Fiscal Year Final Research Report Summary
Development of conductive ceramics for NOx gas decomposition
| Project/Area Number |
08555151
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MIYAYAMA Masaru School of Engineering Associate Professor, 大学院・工学系研究科, 助教授 (20134497)
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| Co-Investigator(Kenkyū-buntansha) |
MUNAKATA Fumio Material Research Laboratory, Nissan Motor Co.LTD.Researcher, 材料研究所, 研究員
KISHIMOTO Akira Institute of Industrial Science Associate Professor, 生産技術研究所, 助教授 (30211874)
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| Project Period (FY) |
1996 – 1997
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| Keywords | nitrogen oxide / perovskite / ceramics / gas adsorption / gas decomposition / gas sensing / ionic conductor |
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| Research Abstract |
This research aims to obtain high and reliable properties for NOx gas sensing and decomposition through controlling adsorption and decomposition behavior of NOx gas by applying electric field to conducting oxide ceramics. N-type conductive Nd_2CuO_4 ceramics showed a decrease of conductance by NO and an increase in conductance by NO_2 gas. Surface chemical binding states of NOX-adsorbates were analyzed with X-ray photoelectron spectroscopy, and different binding states for NO and NO_2 were confirmed for Nd_2CuO_4 and La_<2-x>Ba_xSrCu_2O_<6-delta>. In order to confirm effects of an external electric field on gas adsorption and reaction, changes in conductance by CO gas of SnO_2 thin film on SiO_2/Si substrate were examined under electric fields from the substrate. Acceleration of adsorption of positively-charged species like CO^+, and suppression of adsorption of negatively-charged species like O^- were confirmed under applying a minus bias from the substrate where apparent conductance of SnO_2 is lowered by the minus bias. Current changes of Nd_2CuO_4/stabilized zirconia/Pt element by NOx gas under a constant voltage (an negative bias to the oxide electrode) were examined. Even when two electrodes were exposed to a same atmosphere, increases in DC oxygen-ionic current by NOx gas, independent on ambient oxygen partial pressure, were observed. Changes in mixed potential by NOx and O_2 gases at the oxide electrode were found to be responsible for the enhancement of NOx decomposition and the NOx-sensitive DC ionic current. These results show that adsorption/desorption and decomposition of NOx gases could be controlled by using appropriate oxide material as an electrode and by applying an external bias.
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