▎ 摘　　要

NOVELTY - The preparation method of composite nano-electromagnetic wave absorbing material involves (1) preparing yttrium oxide and tin dioxide composite nanoparticles, (2) performing azide modification on the composite nanoparticles to obtain azide-modified composite nanoparticles, (3) uniformly mixing the azide-modified composite nanoparticles and alkynyl-modified graphene oxide in a mass ratio of (3-4):1, and covalently chelating the azide-modified composite nanoparticles on a alkynyl-modified graphene oxide surface through ring addition reaction, and (4) reducing the graphene oxide. USE - Preparation method of composite nano-electromagnetic wave absorbing material. ADVANTAGE - The method enables preparation of composite nano-electromagnetic wave absorbing material with strong polarization relaxation and excellent absorbing performance. DETAILED DESCRIPTION - The preparation method of composite nano-electromagnetic wave absorbing material involves (1) preparing yttrium oxide and tin dioxide composite nanoparticles, (2) performing azide modification on the composite nanoparticles to obtain azide-modified composite nanoparticles, (3) uniformly mixing the azide-modified composite nanoparticles and alkynyl-modified graphene oxide in a mass ratio of (3-4):1, and covalently chelating the azide-modified composite nanoparticles on a alkynyl-modified graphene oxide surface through ring addition reaction, and (4) reducing the graphene oxide, where the yttrium oxide and tin dioxide composite nanoparticles are prepared by taking methanol as a reaction solvent, adding tin chloride and sodium hydroxide, stirring to dissolve under the action of dispersant, adding yttrium formate and acetylacetonate, and stirring uniformly to form transparent solution, transferring to a reactor, heat-treating at 130-150 degrees C for 50-60 minutes, centrifuging or filtering, washing and drying, calcining, and naturally cooling, where the amount of tin chloride, sodium hydroxide, yttrium formate, acetylacetonate and dispersant per liter of methanol is 0.05-0.06 mol, 3-4 mol, 3-4 mol, 0.02-0.03 mol, and 0.01-0.02 mol, increasing the temperature to 900-1000 degrees C at a heating rate of 50-55 degrees C, keeping the temperature for 5-6 hours, ultrasonically dispersing the composite nanoparticles in dimethyl formamide solution, adding sodium azide, heat-preserving at 50-60 degrees C for 18-24 hours, and post-processing, and the specific method of the step (3) involves ultrasonically dispersing azide-modified composite nanoparticles and ultrasonic dispersed in dimethylformamide solution, adding sodium ascorbate and copper sulfate as a catalyst, heating and refluxing for 4-5 hours, and filtering to obtain the product.