Mesoporous NiO as an ultra-highly sensitive and selective gas sensor for sensing of trace ammonia at room temperature

Abstract In this study, we presented a facile method for the fabrication of an ultra-high sensitive and selective ammonia sensor based on mesoporous NiO. The response and recovery times of mesoporous NiO based sensor were determined for 0.4 ppm ammonia at room temperature (25 °C) and were found to be 54 s and 58 s, respectively. The mesoporous NiO based sensor performed the greatest response to ammonia compared with other gases. In addition, the response value of the mesoporous NiO was up to 91.2 for 0.4 ppm ammonia. Furthermore, the mesoporous NiO sensor remained the original response with no obvious change after 21 days at room temperature, indicating that the sensor exhibited favorable reproducibility and good long term stability. Moreover, formation and sensing mechanism of the mesoporous NiO were also discussed in detail. Therefore, the ammonia sensor based on mesoporous NiO has promising potential for application in the field of ammonia detection.