▎ 摘　　要

NOVELTY - Layered double metal hydroxide/graphene nanocomposite gas-sensitive material, is prepared by (a) uniformly dispersing the graphene oxide in the ethanol aqueous solution to obtain the graphene oxide dispersion, (b) fully dissolving titanium tetrachloride, zinc nitrate hexahydrate and urea in deionized water to obtain a mixed salt solution, (c) uniformly mixing the mixed salt solution and the graphene oxide dispersion to obtain a reaction solution, (d) transferring the reaction liquid to an autoclave, and (e) conducting a hydrothermal reaction at 130-150 degrees C for 20-30 hours, where the concentration of graphene oxide in the reaction solution is 16-17 mg/ml, and the molar ratio of the titanium tetrachloride, zinc nitrate hexahydrate, and urea is (1-3):(4-7):50. USE - The layered double metal hydroxide/graphene nanocomposite gas-sensitive material is used in the detection of nitrogen dioxide gas (claimed). ADVANTAGE - The layered double metal hydroxide/graphene nanocomposite gas-sensitive material achieves uniform coverage of the layered double metal hydroxide nanosheets on the surface of the graphene sheet, forms a large specific surface area, has the three-dimensional composite structure with high electrical conductivity and excellent carrier channels that overcomes the problems of the traditional direct mixing method, significantly improves the room temperature gas sensitivity such as the sensitivity, response speed and detection limit of the layered double metal hydroxide based gas sensor, and realizes the ultra-high room temperature sensitivity and ultra-fast room temperature response of the sensor to ppb level trace nitrogen dioxide. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for preparing the layered double metal hydroxide/graphene nanocomposite gas-sensitive material, comprising the steps of (a)-(e); and (2) a use of the layered double metal hydroxide-graphene nanocomposite gas-sensitive material in the detection of nitrogen dioxide gas, at room temperature, where the detection limit for nitrogen dioxide gas is 50 ppb, the response time is 1-3 seconds, and the response sensitivity to 10 ppm nitrogen dioxide reaches 97%.