Abstract Nitrogen dioxide (NO2), mostly produced from exhaust fumes of cars and factories, has been labelled by the World Health Organization as one of the most hazardous air pollutants. Although metal oxide-based thin films have been employed to detect NO2 earlier, significant challenges remain to be addressed particularly at low detection limits. This is presumably undermined by the low surface area and the high resistivity of metal oxide thin films. Herein, an attempt has been made to overcome these challenges by producing WO3 thin films in the form of nanowires, introducing oxygen vacancies, and immobilizing platinum (Pt) onto the surface of tungsten oxide nanowires. The as-fabricated sensor is highly sensitive, selective and capable of detecting NO2 at 500 ppb level. Furthermore, the sensing response of the as-fabricated sensor can be modulated by tuning the concentration of oxygen vacancy as well as the thickness of the Pt layers. While oxygen vacancy and catalytic properties of Pt are predominant, better electrical conductivity, improved specific surface area of one-dimensional WO3 and the work functions between Pt and WO3 also contribute. A plausible mechanism is proposed for the superior sensing properties of the as-fabricated Pt/WO3 sensor.

中文翻译：

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用于高效 NO2 传感的表面工程 WO3 薄膜

摘要 二氧化氮 (NO2) 主要来自汽车和工厂的尾气，已被世界卫生组织标记为最危险的空气污染物之一。尽管基于金属氧化物的薄膜已被用于较早地检测 NO2，但仍然存在重大挑战，特别是在低检测限时。这可能被金属氧化物薄膜的低表面积和高电阻率所破坏。在此，通过以纳米线的形式生产 WO3 薄膜、引入氧空位以及将铂 (Pt) 固定在氧化钨纳米线的表面上，已经尝试克服这些挑战。制造的传感器具有高度的灵敏度和选择性，能够检测 500 ppb 水平的 NO2。此外，制造好的传感器的传感响应可以通过调整氧空位的浓度以及 Pt 层的厚度来调节。虽然 Pt 的氧空位和催化性能占主导地位，但更好的导电性、一维 WO3 的比表面积提高以及 Pt 和 WO3 之间的功函数也有贡献。针对所制造的 Pt​​/WO3 传感器的卓越传感特性提出了一种合理的机制。