▎ 摘　　要

NOVELTY - Method for preparing nitrogen-doped reduced graphene oxide/cobalt-zinc ferrite composite aerogel wave absorbing material, involves adding ferric chloride hexahydrate and zinc chloride, stirring, continuously adding quantitative polyethylene glycol to beaker to obtain first mixed dispersion, reacting to obtain product containing cobalt-zinc ferrite, cooling, separating the product to obtain water-containing cobalt-zinc ferrite and washing, pre-freezing the water-containing cobalt-zinc ferrite, drying, taking three beakers, adding deionized water to each beaker, adding graphite oxide while stirring to make graphene oxide aqueous dispersion, continuously adding cobalt-zinc ferrite to each beaker, ultrasonically treating and stirring, adding different volumes of ethylenediamine to each beaker, stirring, transferring the second mixed dispersion reaction kettle for hydrothermal reaction to obtain hydrogel, cooling, dialyzing, pre-freezing the aerogel product and drying. USE - Method for preparing nitrogen-doped reduced graphene oxide/cobalt-zinc ferrite composite aerogel wave absorbing material. ADVANTAGE - The method is simple to operate and environmentally-friendly, and does not generate any toxic substances, has excellent electromagnetic wave absorption capacity, wide absorption frequency band, low filling ratio and thin matching thickness, achieves effective absorption of electromagnetic waves in different bands and has important application value in the electromagnetic absorption and electromagnetic shielding. DETAILED DESCRIPTION - Method for preparing nitrogen-doped reduced graphene oxide/cobalt-zinc ferrite composite aerogel wave absorbing material, involves (i) taking 200 ml beaker, adding 60 ml ethylene glycol, 1.08 g ferric chloride hexahydrate, 0.24 g cobalt chloride hexahydrate and 0.14 g zinc chloride, vigorously stirring to make it completely dissolved, (ii) continuously adding quantitative 1.5 g polyethylene glycol to the 200 ml beaker to obtain the first mixed dispersion, (iii) transferring the first mixed dispersion to a reaction kettle with a volume of 100 ml, and thermally reacting at 200 degrees C for 8 hours to obtain product containing cobalt-zinc ferrite, (iv) after completing the reaction, cooling to normal temperature, magnetically separating the product to obtain water-containing cobalt-zinc ferrite, and washing it with deionized water several times to make the pH of the water-containing cobalt-zinc ferrite reach neutral, (v) pre-freezing the water-containing cobalt-zinc ferrite for 12 hours, transferring it to a freeze dryer and drying at low temperature for 24 hours to obtain pure cobalt-zinc ferrite, (vi) taking another three 100 ml beakers, adding 30 ml deionized water to each beaker, adding 90 mg graphite oxide while stirring to make graphene oxide aqueous dispersion, (vii) continuously adding 30 mg cobalt-zinc ferrite obtained in the step (v) to each 100 ml beaker, ultrasonically treating for 30 minutes and stirring for 30 minutes until the dispersion is uniform, (viii) adding different volumes of ethylenediamine to each 100 ml beaker, and stirring for 30 minutes to obtain a second mixed dispersion, where the added volume of ethylenediamine is 0, 250 and 350 mu l respectively, (ix) transferring the second mixed dispersion to a 50 ml reaction kettle for hydrothermal reaction to obtain hydrogel, (x) after completing the reaction, cooling to normal temperature, and dialyzing obtained hydrogel to obtain aerogel product and (xi) pre-freezing the aerogel product for 12 hours, transferring it to a freeze dryer and drying at low temperature for 48 hours to obtain the aerogel product.