Moleculer Recognition and Decomposition by Functional Ceramics

从环境安全的观点来看，用简单的装置对NOx或CO等有毒气体进行选择性气体传感被认为是一项重要的技术，尤其是对NOx或其他大气污染气体的生产率的控制和反应过程的控制以及分解过程的开发是环境安全的最重要的课题之一。其电阻通过引入水蒸气、氧化气体（NOx、Cl 2）或还原气体（CO、H 2）而改变。本文研究了陶瓷异质接触的电性能及其在化学传感器中的应用。当我们使用CuO（p型半导体）和ZnO（n型半导体）烧结体作为热电接触时，通过CuO-ZnO界面的电流因还原性气体的引入而增加，其气敏性随外加电压的变化而变化。研究了添加剂对CO气敏特性的影响 ...更多信息 讨论了CuO或CuO/ZnO异质接触。添加剂对CuO粉末压坯的CO气敏性能有影响，钠或碱金属的添加构成了CuO粉末压坯的CO敏感表面。碱金属掺杂对CuO表面性质的影响反映在CuO/ZnO异质结的气敏特性上，Na^+掺杂的CuO/ZnO异质结表现出选择性CO气敏特性。通过热重分析和ZnO表面产物的程序升温脱附，研究了SiC/ZnO异质接触材料的氮氧化物（NOx）敏感机理，发现只有当SiC/ZnO异质接触样品在湿空气中充分暴露于NOx时，其电流才显著降低。采用6层CuO-ZnO系统的组分递减层堆叠法制备了CuO/ZnO异质结，并对通过CuO/ZnO界面的废气进行了流动气相色谱分析。观察到CO向CO_2转化数随外加电场的变化，并在CuO-ZnO界面上进行了电场控制的CO在p-n半导体界面上的氧化反应。少

Selective gas sensing of poisonous gases such as NOx or CO by a simple device is thought to be important technique for the view point of safe environment, control of productivity and control of reaction process and development of decomposition process pf NOx or other atmospheric pollution gases are one of the most important subjects especially for safe environment.Heterocontact is one of the electric devices, of which electrica resistance is changed by the introduction of water vapor, oxidizing gases (NOx , Cl2) or reducing gases (CO,H2). The authors have been studied on the electric properites of hetercontact of ceramics and its application to chemical sensors. When we used CuO (p-type semiconductor) and ZnO(n-type semiconductor) sintered compacts for hueterocontact, the electric current thorough CuO-ZnO interface increased by the introduction of reducing gases and its gas sensitivity varied as a function of applied voltage. The effect of additives on CO gas sensing characteristics of … More CuO or Cuo/ZnO heterocontact is discussed. Some additives affect the CO gas sensing properties of CuO powder compact and CO sensitive surface is constructed by sodium or ther alkali metal addition. Variation in surface properties of CuO by the alkali metal addition would be reflected to gas sensing characteristics of CuO/ZnO heterocontact and Na^+ added CuO/ZnO heterocontact shows selective CO gas sensing characteristics. The result gives us a useful information for the material design of CO sensor based on CuO ceramics or CuO based heterocontact.The nitrogen oxide (No_x) sensing mechanism of SiC/ZnO heterocontact is investigated by thermogravimetric analysis and temperature-programd desorption of surface product on ZnO.A pronounced decrease in electric current was observed only when a SiC/ZnO heterocontact specimen was suffiently exposed to NOx with wet air. From these results, formation of zinc nitrite on the ZnO surface is suggested and it would affect the electron transfer process at the ZnO-SiC interface.CuO/ZnO heterocontct is fabricated by the stacking of 6 layrs of declined composition of CuO-ZnO system and the exhaust gas passing through CuO/ZnO interface is analyzed by gas chromatography with flowing system. The variation of turnover number from CO to CO_2 as a function of applied electric field is observed and electric field controlled CO oxidative reaction at p-n semiconductor interface is performed at CuO-ZnO interface. Less