High sensing performance for n-butanol detection based on ultrathin ZnO nanosheets at low temperature

Low-temperature n-butanol gas sensors with excellent performance are of critical importance to environmental monitoring applications. In this work, ZnO with varied morphologies was synthesized via a facile hydrothermal method and characterized using XRD, SEM, XPS, and TEM. Comparative evaluation of sensing capabilities reveals that the sensor based on porous ultrathin ZnO nanosheets exhibits superior n-butanol sensing performance at 40 °C, featuring a high response (125.3/100 ppm and 5.0/1 ppm), which is about 4.5–18.9 times higher than that of other samples, along with fast response/recovery times (9/20 s). Furthermore, the sensor displays remarkable selectivity for n-butanol, with response ratios 2.3 to 38 times higher than those for interfering gases such as ethanol, methanol, formaldehyde, and benzene. Moreover, it demonstrates excellent linearity (R 2 = 0.9802) with a theoretical limit of detection as low as 38 ppb. The improved performance is attributed to the absorption sites induced by oxygen vacancies and the unique nanosheet structure. Additionally, density functional theory (DFT) and thermodynamic calculations further confirm that the (100) plane exhibits strong adsorption of n-butanol, accompanied by higher energy released from the sensing reaction. These factors collectively contribute to the high response, low operating temperature, and superior selectivity of the porous ultrathin ZnO nanosheet to n-butanol. • Porous ultrathin ZnO nanosheet was synthesized. • It shows a high response to n-butanol at room temperature. • The oxygen vacancy and the unique structure contribute to enhanced performance. • DFT calculations shows (100) plane strongly adsorbs n-butanol for high selectivity.