Applied Physics Laboratory & Electrical Engineering, University of Washington, Seattle, Washington 98105, USA.
Phys Chem Chem Phys. 2013 Apr 14;15(14):5017-21. doi: 10.1039/c3cp43454k.
Environmental humidity is an important factor that can influence the sensing performance of a metal oxide. TiO2-(B) in the form of nanowires has been demonstrated to be a promising material for the detection of explosive gases such as 2,4,6-trinitrotoluene (TNT). However, the elimination of cross-sensitivity of the explosive detectors based on TiO2-(B) toward environmental humidity is still a major challenge. It was found that the cross-sensitivity could be effectively modulated when the thin film of TiO2-(B) nanowires was exposed to ultraviolet (UV) light during the detection of explosives under operating conditions. Such a modulation of sensing responses of TiO2-(B) nanowires to explosives by UV light was attributed to a photocatalytic effect, with which the water adsorbed on the TiO2-(B) nanowire surface was split and therefore the sensor response performance was less affected. It was revealed that the cross-sensitivity could be suppressed up to 51% when exposed to UV light of 365 nm wavelength with an intensity of 40 mW cm(-2). This finding proves that the reduction of cross-sensitivity to humidity through UV irradiation is an effective approach that can improve the performance of a sensor based on TiO2-(B) nanowires for the detection of explosive gas.
环境湿度是影响金属氧化物传感性能的一个重要因素。已经证明，纳米线形式的 TiO2-(B) 是探测 2,4,6-三硝基甲苯（TNT）等爆炸气体的一种很有前途的材料。然而，消除基于 TiO2-(B) 的爆炸探测器对环境湿度的交叉敏感性仍然是一个主要挑战。研究发现，当 TiO2-(B) 纳米线薄膜在操作条件下探测爆炸物时暴露于紫外（UV）光下，交叉敏感性可以得到有效调节。这种 UV 光对 TiO2-(B) 纳米线对爆炸物的传感响应的调制归因于光催化效应，其中吸附在 TiO2-(B) 纳米线表面的水被分解，因此传感器的响应性能受到的影响较小。结果表明，当暴露于强度为 40 mW cm(-2) 的 365nm 波长的紫外光下时，交叉敏感性可降低至 51%。这一发现证明，通过紫外辐照降低对湿度的交叉敏感性是一种有效方法，可以提高基于 TiO2-(B) 纳米线的传感器探测爆炸气体的性能。
