A metal-oxide doped SnO2-based microsensor for measuring H2S concentration

This study focused on developing a hydrogen sulfide (H₂S) gas microsensor using nanometal oxides of copper oxide-doped tin dioxide. Electrospinning and high-temperature calcination were adopted to fabricate a high-surface area and porous hollow nanofibrous gas sensing film. The film that served as a sensing mechanism on the heterojunction of the microsensor exhibited a high resistance change rate; therefore, the gas-sensing sensitivity was effectively improved. The ceramic ring-based sensor was coated with a nanosensing film, on which gold sensing electrodes were formed through sputtering by using a shadow mask. Thus, a sensing mechanism was completed that allowed the absorption of the gases to be tested. A heating wire was designed in the chamber of the ceramic ring to control the local temperature of the sensing structure. The response level and repeatability of the device to the gases were effectively enhanced. Results indicated that the microsensor could sense H₂S at a concentration of 1-100 ppm, had a sensitivity of 0.39 MΩ/ppm, and possessed response and restoration times of 5 ± 0.12 s and 12 ± 0.24 s, respectively.