Outstandingly selective n-butanol gas sensor based on ZnS/NiO lychee-shaped nanospheres

In this paper, ZnS/NiO p-n heterojunction microspheres were fabricated via a two-step hydrothermal approach. The sensing properties of composites with different ZnS contents were investigated by regulating the ratio of Zn. When containing 25 mol% ZnS, the ZnS/NiO nanosphere sensor achieved a response of 125. The response was improved by a factor of about 83.3 compared to pure NiO. The sensor functions optimally at a temperature of 225 ℃, and it possesses excellent selectivity, a rapid response/recovery time (49/44 s), and long-term stability. Therefore, this paper provides a hydrothermal method to prepare ZnS/NiO nanocomposites with heterojunction, specifically designed to detect n-butanol. After performing a series of characterizations, it was determined that the enhancement of the gas-sensitive properties could be related to the construction of ZnS/NiO heterojunctions and the increase in oxygen vacancies.