摘要： Gas sensors with the ability to detect gaseous species in a quantitative and qualitative manner play an important role in various aspects in our daily lives. They can function as a feasible means to monitor air quality, environmental pollution, chemical detection, control of chemical processes, food quality, and medical diagnosis and so forth. One-dimensional (1D) nanostructures at least one dimension in the range of 1–100 nm (nanowires, nanorods, nanoribbons or nanobelts, nano?bers) have long been considered as promising building blocks for gas sensors [1–7]. The fascinating features of nanowires for gas sensing include high surface-to-volume ratio, sensitive surface, high crystallinity, high carrier mobility, low power consumption and ease for device integration [2, 6, 8, 9]. In 2001 nanowires were initially employed to fabricate gas sensors as proof-of-concept [2, 3]. Afterwards nanowires are drawing fast growing interest in the ?eld of gas sensing with an outcome of over 1200 publications in past 15 years from the Web of Science using the keywords nanowire and gas sensor (Fig. 7.1). It is important to note that among these publications metal oxide nanowires hold a dominant position, while other nanowires including organic polymers, metals, and other semiconductors only register a small part (12.6%). It is not strange that n-type ZnO and SnO2 nanowires are the most extensively studied materials for gas sensing because the electron mobility in ZnO and SnO2 is very high (160 and 200 cm2 V(cid:1)1 s(cid:1)1, respectively) with respect to that of other metal oxides such as In2O3, WO3 and TiO2 (100, 10 and 0.4 cm2 V(cid:1)1 s(cid:1)1, respectively).