▎ 摘　　要

NOVELTY - A palladium-doped reduced graphene oxide/zinc oxide-tin oxide heterojunction quaternary composite material comprises particle (B) formed by agglomeration of particles (A) with a particle size of 20-40 nm. The particles (A) are based on reduced graphene oxide with two-dimensional network structure. Sheet-like zinc oxide nanomaterials and sheet-like tin oxide nanomaterials are coated on the surface of the substrate. The zinc oxide and tin oxide composite form n-n type heterojunction. The zinc oxide, tin oxide and reduced graphene oxide form p-n heterojunctions, respectively. Palladium nanoparticles are doped in zinc oxide, tin oxide and reduced graphene oxide. The amount of reduced graphene oxide in the composite material is 1.5-6% of the total mass of zinc oxide and tin oxide. USE - Palladium-doped reduced graphene oxide/zinc oxide-tin oxide heterojunction quaternary composite material for hydrogen sensor as gas-sensing material (claimed). ADVANTAGE - The composite material provides hydrogen sensor with high selectivity, quick response and low concentration detection. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) preparation of the palladium-doped reduced graphene oxide/zinc oxide-tin oxide heterojunction quaternary composite material, which involves (1) adding sheet-like zinc oxide nanomaterial and stannous chloride to the water above the purity of deionized water, mixing, adding dimethylformamide, adding sodium hydroxide solution in drops, adding palladium chloride, stirring and mixing, obtaining mixture, (2) adding graphene oxide powder to water above the purity of deionized water, ultrasonically processing at 60-90 W for 1-3 hours, obtaining graphene oxide dissociation solution, (3) transferring the graphene oxide dissociation solution and the mixture to autoclave, reacting at 160-200degrees Celsius for 15-20 hours, cooling, washing and drying, and calcining at 450-550degrees Celsius for 2-6 hours. The added amount of the graphene oxide powder is 1.5-6% of the total mass of zinc oxide and tin oxide. The amount of tin oxide is obtained by theoretical calculation from the addition of stannous chloride; (2) use of the palladium-doped reduced graphene oxide/zinc oxide-tin oxide heterojunction quaternary composite material in hydrogen sensor as gas-sensing material; and (3) preparation of hydrogen sensor, which involves grinding the composite material to obtain a powder with a particle size of 0.5-5 microns, dissolving the powder in a mixed solvent of organic solvent and deionized water with a purity of above water, mixing to obtain slurry, applying the slurry to the test electrode area of the micro-hot plate chip, drying, annealing at 280-350degrees Celsius for 2-4 hours, obtaining gas sensor, placing in sealed air chamber, energizing heating electrode of micro-hot plate chip, and aging.