▎ 摘　　要

NOVELTY - A graphene-coated alpha -ferric oxide composite-based sensor consists of alumina ceramic tube with two ring-shaped gold electrodes, a sensitive material film coated on the electrode, and a nickel-cadmium alloy coil provided in the ceramic tube. The sensitive material is a graphene-coated alpha -ferric oxide composite obtained by stirring 100-200 mg ferric nitrate nonahydrate and 10-20 mL deionized water for 30-60 minutes to obtain ferric nitrate solution, ultrasonically treating 5-10 mg lyophilized graphene oxide powder and 10-20 mL deionized water for 45-60 minutes to obtain graphene oxide solution, stirring 5-10 mL graphene oxide solution and 10-20 mL ferric nitrate solution for 30-60 minutes, reacting at 70-90 degrees C in water bath for 3-6 hours to obtain dark red solution, hydrothermally reacting the red solution at 160-190 degrees C for 15-20 hours, cooling to room temperature, high-speed centrifuging, washing with deionized water and absolute ethanol, freeze-drying, and calcining. USE - Graphene-coated alpha -ferric oxide composite-based sensor used for detecting nitrogen oxide. ADVANTAGE - The graphene-coated alpha -ferric oxide composite-based sensor has high specific surface area, gas adsorption capacity, fast carrier mobility and conductivity. The surface chemistry of the gas being detected and the formation of charge transfer between graphene and alpha -ferric oxide, are increased, thereby effectively improving sensor sensitivity with respect to nitrogen oxide and lowers the operating temperature of the device to room temperature, such that nitrogen oxide content can be detected in the microenvironment. DETAILED DESCRIPTION - The freeze-drying is performed at -50 degrees C to -30 degrees C for 12-18 hours. The calcination is performed at 400-600 degrees C for 1-3 hours. An INDEPENDENT CLAIM is included for manufacture of graphene-coated alpha -ferric oxide composite-based sensor.