Ppb-Level Ammonia Sensing of Marigold Flower-Like NiO Nanostructure for Freshwater Fish Freshness

Fish freshness monitoring is now paramount for maintaining a healthy lifestyle. This letter represents the development of a marigold flower-like NiO nanostructure-based chemiresistor that can sense ppb-level ammonia for monitoring freshwater fish freshness. A simple low-temperature hydrothermal method was utilized to synthesize the sensing material. Using X-ray diffraction and a field emission scanning electron microscope, the synthesized material was examined in terms of structure and morphology. The sensor was fabricated using the drop casting method over gold interdigitated electrodes on alumina substrate. According to the gas sensing study, the sensor was more responsive to ammonia at 250 °C. The sensor device gained a response of 10% in the presence of 1 parts per million (ppm) ammonia. The response and recovery times were about 150 and 180 s, respectively, for 1 ppm ammonia. The experimental limit of detection of the sensor was 100 ppb. The proposed sensor is suitable for monitoring freshwater fish freshness.