Chemiresistive n-butanol gas sensors based on Co3O4@ZnO hollow-sphere-array thin films prepared by template-assisted magnetron sputtering

Abstract

Rapid and accurate detection of n-butanol in the environment is crucial owing to its negative effects on human health. Herein, gas sensors based on Co3O4@ZnO hollow-sphere-array thin films modified using Au particles are successfully prepared via template-assisted magnetron sputtering for detecting n-butanol. The best sensor performances are achieved when the thicknesses of the sputtered ZnO and Co3O4 films are 60 and 1.2 nm, respectively, and the sputtering time of the Au particles is 10 s. Furthermore, the best sensor exhibits an exceptionally high response to an n-butanol concentration of 100 pm at 275 °C (Ra/Rg = 260), a short response/recovery time (1 s/92 s), a considerably lower limit of detection (Ra/Rg = 5.8 at n-butanol concentration = 100 ppb) as well as high selectivity and repeatability. The remarkable sensing performance of the proposed sensors can be mainly attributed to the charge transfer induced by the Co3O4–ZnO heterojunction formation and the catalytic and spillover effects of the Au particles. This study is important because it provides a simple preparation method for high-performance semiconductor gas sensors using magnetron sputtering, which would enable future large-scale and integrated preparation of high-performance gas sensors.