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Study on Realization of Optical Hydrogen Sensor Operating at Room Temperature

常温光学氢传感器的实现研究

基本信息

批准号：
07555192
负责人：
TAKATA Masasuke
金额：
$ 12.22万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

The objective of this research was to search materials of thin film for optical hydrogen sensor and to improve its detection characteristics at room temperature. The sensor consisting of Pd/WO_3 (double-layered thin film) showed good sensing characteristics at room temperature. The sensor consisting of Pd/MoO_3 had faster response to detection of low concentration of hydrogen than that of Pd/WO_3. Moreover, it was found that the transmittance of Pd thin film increased with its hydrogenation and the phenomenon could be applied to a new hydrogen sensor. The strong points of the sensor are simple structure and fast response to hydrogen detection. Although thicker Pd film showed a higher sensitivity, it had a lower durability. Moreover, the sensor indicated lower recovery rate than response rate. The insertion of buffer layer such as W film between Pd film and glass substrate was effective in suppression of the surface morphology change and achieved a great durability. The change in reflectance with hydrogen desorption indicated distinctive characteristics with three-stage curve, which was due to thei phase transformation of Pd hydride. The recovery rate of the sensor increased with oxygen partial pressure, which suggested that the rate-determining step for dehydrogenation was hydrogen desorption with water forming reaction on Pd hydride surface, and adsorbed oxygen assisted the hydrogen desorption process. It was discovered that a very small quantity of Pt supported on Pd surface considerably accelerated the recovery process because of high water forming rate on Pt surface. Furthermore, double-layered thin film consisting of Pd/Y was found to indicate high sensitivity even for low concentration of hydrogen and fast response to hydrogen detection.

本研究的目的是寻找用于光学氢传感器的薄膜材料，并改善其在室温下的检测特性。由Pd/WO_3（双层薄膜）组成的传感器在室温下表现出良好的传感特性。Pd/MoO_3构成的传感器对低浓度氢气的检测响应速度快于Pd/WO_3。此外，Pd薄膜的透过率随其加氢而增加，这一现象可应用于新型的氢传感器。该传感器的优点是结构简单，对氢气的检测响应速度快。虽然较厚的钯膜具有较高的灵敏度，但其耐久性较低。此外，传感器显示的恢复率低于响应率。在Pd膜和玻璃基板之间插入W膜等缓冲层，有效抑制了表面形貌的变化，获得了较好的耐久性。反射率随氢脱附的变化表现出明显的三段式曲线特征，这是由于氢化钯的相变所致。传感器的回收率随氧分压的增大而增大，说明脱氢的决定速率步骤是氢在Pd氢化物表面的脱附成水反应，吸附的氧辅助了氢的脱附过程。研究发现，由于铂表面的成水速率高，极少量的铂负载在钯表面上，可以显著加快回收过程。此外，Pd/Y双层薄膜对低浓度氢也具有很高的灵敏度，对氢检测的响应速度也很快。