▎ 摘　　要

NOVELTY - Sensor (10) comprises a graphene sheet (12) positioned on a substrate (11); and tin oxide nanoparticles (13b) and nickel oxide nanoparticles (13a) doped on the graphene sheet. USE - The sensor is useful in system for detecting ammonia gas (claimed), and in fields of ammonia gas emission e.g. chemical engineering, food technology, thermal power plant, environmental protection, medical diagnosis, and industrial process. ADVANTAGE - The sensor is capable of stably detecting ammonia gas within 250 seconds at 20-35 degrees C in 0.1-500 parts/million (ppm), with a fast response rate and a low concentration of 0-10 ppm and a high concentration of 10-100 ppm; has high-sensitivity to heat, thus have limitations in use depending on the environment, high selectivity and high stability, and low reproducibility due to oxidation of metal components, high-performance real-time detection through gas resistance change, and efficient and simple manufacturing process for real-time monitoring of ammonia gas. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for manufacturing sensor. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the sensor. Sensor (10) Substrate (11) Nickel oxide nanoparticles (13a) Tin oxide nanoparticles (13b)