An in situ electrospinning route to fabricate NiO-SnO₂ based detectors for fast H₂S sensing

Hydrogen sulfide (H₂S) is a toxic and flammable chemical, even in low concentration. In this study, an in situ electrospinning strategy was developed to directly deposit the sensitive materials of nickel oxide (NiO)-doped SnO₂ nanofiber on alumina substrates, resulting in the fast H₂S detection. The electrospun fiber could be deposited on to the alumina tube directly, and remain there during calcination. Using this method, the NiO-doped SnO₂ nanofibers fabricated and manifested a fast response, fast recovery, and high selectivity at a low temperature (150 °C). A 15% atom NiO-doped SnO₂ nanofiber-containing H₂S detector presented a high response (1352), low response time (23 s), and low recovery time (38 s) while detecting a concentration of 50 ppm H₂S at 150 °C. Compared to conventional methods, the H₂S detector based on the in situ electrospinning method showed a higher sensitivity, faster response, and faster recovery. Furthermore, the superior performance of the detector can be ascribed to the thinner film and non-interrupted fiber structure. Additionally, the transformation of NiO to Ni₃S₂, confirmed by the x-ray photoelectron spectroscopy under a H₂S atmosphere, suggested the main reason for the detector's high performance. The high performance of the NiO-doped SnO₂ suggests a strategy for gas detectors, biodetectors, and semiconductor devices.