▎ 摘　　要

NOVELTY - A nitrogen dioxide sensing element based on reduced graphene oxide-tin oxide nanometer composite material comprises an electrode element and an reduced graphene oxide-tin oxide nano composite material uniformly coated on the electrode element, where the microstructure of the reduced graphene oxide-tin oxide nano composite material is uniformly grown on the reduced graphene oxide sheet layer, the tin oxide nanospheres have a diameter of 40-70 nm and the tin oxide nanospheres have a tetragonal cassiterite phase structure. USE - Nitrogen dioxide sensing element based reduced graphene oxide-tin oxide nanometer composite material. ADVANTAGE - The gas sensor solves the problems of high operating temperature of the conventional nitrogen dioxide gas sensor, low sensitivity and long recovery time of the graphene gas sensor and has better application value and development prospect. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for preparing nitrogen dioxide sensing element based on reduced graphene oxide-tin oxide nanometer composite material, which involves mixing an anhydrous ethanol and graphene oxide dispersion in a ratio of 1:1-1:2 by volume, stirring uniformly, adding 5-7 mmol sodium citrate dihydrate and 2-4 mmol stannous chloride dihydrate, continuing stirring for 20-40 minutes to obtain a mixed solution, charging the mixed solution into the reaction vessel, reacting at 160-200 degrees C for 14-18 hours, cooling to room temperature, centrifuging the product to remove the supernatant, washing, drying, heating to 500 degrees C in a tube furnace at 2 degrees C/minute under argon gas atmosphere, heating for 1-3 hours, reducing to room temperature, raising the temperature to 200 degrees C at 2 degrees C/minute in an air atmosphere, heating for 10-12 hours to a obtain reduced graphene oxide-tin oxide nanocomposite, wet-milling the reduced graphene oxide-tin oxide nanocomposite to obtain a paste slurry, which iscoated on the ceramic tube electrode and naturally dried at room temperature for 1 hour and above, coating the ceramic tube electrode with reduced graphene oxide-tin oxide nanocomposite, connecting to the susceptor, mounting on the aging table of the benchtop gas sensor and aging at 180-220 degrees C for 10-14 hours to obtain the nitrogen dioxide sensing element based on reduced graphene oxide-tin oxide nanometer composite material.