Titanium oxide nanotube thin films formed by anodic oxidation of titanium metal exhibit high reactivity towards various gases at high temperatures. To date, various types of gas sensors using titanium oxide nanotube films have been proposed. Previously, we proposed a microscale gas sensor with titanium oxide nanotube thin films fabricated by local anodization of titanium microelectrodes. In this study, to improve the response characteristics of titanium oxide nanotube-based microscale gas sensors, we decorated titanium oxide nanotube films with catalytic noble metals of platinum nanoparticles using atomic layer deposition technique. We confirmed that due to Pt decoration the sensitivity was significantly improved for hydrogen and carbon monoxide gases. The detection limit of hydrogen gas was found to be in the sub-ppm range. The response characteristics of hydrogen and carbon monoxide gases were analyzed in detail based on the Langmuir adsorption model. It was found that when the concentration of gas increased, the adsorption mode changed from adsorption on the top surface of the film to that on the inner wall of the titanium oxide nanotubes. We also show that the trace amounts of carbon monoxide gas in a mixed gas containing oxygen and nitrogen can be detected.

通过钛金属的阳极氧化形成的氧化钛纳米管薄膜在高温下对各种气体表现出高反应性。迄今为止，已经提出了使用氧化钛纳米管膜的各种类型的气体传感器。以前，我们提出了一种带有通过钛微电极的局部阳极氧化制备的氧化钛纳米管薄膜的微型气体传感器。在这项研究中，为了改善基于氧化钛纳米管的微型气体传感器的响应特性，我们使用原子层沉积技术用铂纳米颗粒的催化贵金属装饰了氧化钛纳米管膜。我们证实，由于采用了Pt装饰，对于氢气和一氧化碳气体的灵敏度大大提高。发现氢气的检出限在亚ppm范围内。基于Langmuir吸附模型，详细分析了氢气和一氧化碳气体的响应特性。发现当气体浓度增加时，吸附模式从在膜的顶表面上的吸附改变为在氧化钛纳米管的内壁上的吸附模式。我们还表明，可以检测到包含氧气和氮气的混合气体中的痕量一氧化碳气体。