Basic Research for Development of Ceramic Odor Sensors

陶瓷气味传感器开发的基础研究

基本信息

批准号：
01470082
负责人：
YAMAZOE Noboru
金额：
$ 4.48万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-01470082/
关键词：
Semiconductor Gas Sensor Microstructure Control Surface Modification Odor Sensor

项目摘要

Sensing properties of semiconductor gas sensor were extensively improved by microstructrure control and by surface modification. A new design concept of semiconductor gas sensor was constructed in the present research.The sensitivity of snO_2 gas sensor was enhanced by controlling crystallite size (D) and thickness of space charge layer (L) of SnO_2 and the dispersion state of Pd promoter. The sensitivity increased with decreasing D close to 2L (=ca. 6 nm for pure SnO_2), while for Al^<3+>-doped SnO_2 it was very high even at large D because the doping brings about large L values. Therefore it was found that the sensitivity could be promoted when D/2L was controlled to be close to unity or less. On the other hand, the sensitivity of Pd-SnO_2 sensor was enhanced by highly dispersing small Pd particles on SnO_2 surface. The Pd complex fixation method was found to be the most excellent method to obtain the high dispersion of Pd particle.The improvement of the selectivity was attained by modifying the SnO_2 surface using foreign oxide additives. The sensitivity of SnO_2 gas sensor to ethanol gas was enhanced by adding basic oxide such as La_2O_3, probably because the oxidation of C_2H_5OH via dehydrogenation through CH_3CHO intermediate proceed favorably on the basic surface. Similar results were obtained for Pd-La_2O_3-In_2O_3 element effectively. On the other hand, CuO was a unique additives to enhance sensing properties of SnO_2 element to H_2S. CuO-SnO_2 element showed the extraordinary high sensitivity and selectivity, and switching-like recovery response on turning off H_2S. The change of state between CuO and CuS was found to be responsible for such unique sensing properties.

通过微结构控制和表面改性，半导体气体传感器的传感性能得到了广泛改善。本研究构建了半导体气体传感器的新设计理念。通过控制SnO_2微晶尺寸(D)和空间电荷层(L)厚度以及Pd促进剂的弥散状态来提高snO_2气体传感器的灵敏度。随着D减小到接近2L(对于纯SnO_2约6nm)，灵敏度增加，而对于Al^3+掺杂的SnO_2，即使在大D下灵敏度也非常高，因为掺杂带来了大L值。因此发现，当将D/2L控制在接近于1或更低时，可以提高灵敏度。另一方面，通过在SnO_2表面高度分散小Pd颗粒，提高了Pd-SnO_2传感器的灵敏度。发现Pd络合物固定法是获得Pd颗粒高分散性的最佳方法。通过使用外来氧化物添加剂对SnO_2表面进行改性来提高选择性。添加La_2O_3等碱性氧化物提高了SnO_2气体传感器对乙醇气体的灵敏度，这可能是因为CH_3CHO中间体脱氢氧化C_2H_5OH在碱性表面顺利进行。对于Pd-La_2O_3-In_2O_3元素也能有效地得到类似的结果。另一方面，CuO是一种独特的添加剂，可以增强SnO_2元素对H_2S的传感性能。 CuO-SnO_2元件表现出极高的灵敏度和选择性，以及关闭H_2S时的开关式恢复响应。人们发现 CuO 和 CuS 之间的状态变化是造成这种独特传感特性的原因。