Studies of Hydrogen-pumping Function of Proton-conducting Ceramics and Their Applications

本研究的目的是阐明质子导电陶瓷的电化学氢泵的功能，并为氢泵在工业过程和科学仪器中的应用建立指导原则。同时，本课题的研究目标之一是开发适用于氢泵的新型质子导电陶瓷，并对质子导电陶瓷用于氢泵的电极反应和正负极电极行为进行了详细的研究。通过对电极材料的微观结构、水蒸气的含量以及工作温度等因素的研究，可以明确提高抽气能力的因素。在此基础上，我们成功地构建了一台高性能的氢泵，该泵可以在大于1Acm ~ 2的电流密度下进行电化学抽<-2>氢，并将氢泵功能与质子导电陶瓷的氢敏功能相结合，设计了混合气体中氢分压的调节器，并证实了其工作良好。氢泵成功地应用于密闭容器电化学除湿器和不需要氢标准物质的氢传感器。此外，还合成了以Sr_2YTaO_6、LaSrAlO_4、<5.8>La_WO_3<11.7>、La_3NbO_7、LaScO_3、SrZrO_3等为基的质子导电固体氧化物。

The objectives of this study are to clarify the function of electrochemical hydrogen pump of proton-conducting ceramics and to establish the guiding principles for applying the hydrogen pump to industrial process and scientific instruments. Also, the creation of new proton conducting ceramics suitable for the hydrogen pump is one of the aims of our study.Hydrogen gas electrode reaction and the electrode behavior of anode and cathode of the hydrogen pump using a proton-conducting ceramic were investigated in detail from the experimental results. The microstructure of electrode material, the content of water vapor and the operation temperature that would enable to enhance the pumping capacity could be clarified in this work. Based on these results, we succeeded in constructing a high performance hydrogen pump which could electrochemically pump the hydrogen gas at higher current density than 1Acm^<-2>.Combining the hydrogen-pumping function with the hydrogen-sensing function of proton-conducting ceramic, the regulator of hydrogen partial pressure in the gas mixture was devised and it was confirmed to work well. Hydrogen pumps were successfully applied to an electrochemical dehumidifier for closed vessels and the hydrogen sensors which need no hydrogen standard material. This kind of a pump showed the possibility of applying to denitration equipment for exhaust gas from internal combustion engines.Furthermore, several kinds of proton-conducting solid oxide based on Sr_2YTaO_6, LaSrAlO_4, La_<5.8>WO_<11.7>, La_3NbO_7, LaScO_3, SrZrO_3 etc.were newly synthesized.