H₂S Detection by Vertically Aligned CuO Nanowire Array Sensors

TLDR

Various mechanisms have been proposed to explain low‑ and high‑concentration H₂S detection. The authors fabricated vertically aligned CuO nanowire arrays via in situ micromanipulation in an SEM and modeled low‑concentration detection by an oxygen adatom process and high‑concentration detection by an interface reaction, enabling selective sensing. The sensors detect air‑diluted H₂S at parts‑per‑billion levels and show strong selectivity against H₂, CO, and NH₃.

Abstract

Chemical sensors based on vertically aligned p-type CuO nanowire arrays have been fabricated by in situ micromanipulation in a scanning electron microscope. The sensors are capable of detecting air-diluted H2S to the parts per billion level. Different mechanisms have been proposed for the detections of low and high concentrated H2S. The recoverable detection for low concentrations can be explained by an oxygen adatom related process, while an interface reaction model fits for the high concentration detection, which also explains the exponential sensing response. Furthermore, selective detection for H2S has also been investigated. The sensor demonstrated strong selectivity for H2S, as compared with the responses to high concentrations of H2, CO, and NH3.