▎ 摘　　要

NOVELTY - Preparing graphene-based composite wave absorbing material comprises e.g. (1) weighing 3-4 g graphite powder, 2.5-3.5 g persulfate and 2-4 g phosphorus pentoxide, and then adding into 15-18 ml concentrated sulfuric acid, and stirring at 80-85 degrees C for 6-8 hours, then cooling the reaction system to room temperature, diluting with distilled water to a pH of 4-5, allowing to stand for 20-24 hours, filtering, washing with water until the filtrate is neutral, and drying the obtained product to constant weight at room temperature to obtain pre-oxidized graphite; adding graphite to 120-150 ml concentrated sulfuric acid and uniformly stirring, and slowly adding 15-18 g strong oxidant in the ice water bath, stirring uniformly, slowly heating to 35-40 degrees C to react for 2-4 hours, slowly adding distilled water into the system, reacting for 2-3 hours, re-adding distilled water and stir until the system is uniform, adding hydrogen peroxide, the solution turns bright brown, centrifuging, and washing. USE - The method is useful for preparing graphene-based composite wave absorbing material. ADVANTAGE - The composite wave absorbing material has low preparation cost, simple technique, low density, strong absorbing ability and frequency bandwidth, and has important use value in microwave absorption and electromagnetic wave shielding. DETAILED DESCRIPTION - Preparing graphene-based composite wave absorbing material comprises (1) weighing 3-4 g graphite powder, 2.5-3.5 g persulfate and 2-4 g phosphorus pentoxide, and then adding into 15-18 ml concentrated sulfuric acid, and stirring at 80-85 degrees C for 6-8 hours, then cooling the reaction system to room temperature, diluting with distilled water to a pH of 4-5, allowing to stand for 20-24 hours, filtering, washing with water until the filtrate is neutral, and drying the obtained product to constant weight at room temperature to obtain pre-oxidized graphite; adding graphite to 120-150 ml concentrated sulfuric acid and uniformly stirring, and slowly adding 15-18 g strong oxidant in the ice water bath, stirring uniformly, slowly heating to 35-40 degrees C, continuously to react for 2-4 hours, slowly adding 250-300 ml distilled water into the system, followed by reacting for 2-3 hours, the temperature of the control system does not exceed to 50 degrees C, re-adding 300-350 ml distilled water and stir until the system is uniform, then adding 10-40 ml of 30% concentration of hydrogen peroxide, the solution turns bright brown, centrifuging, then washing with hydrochloric acid solution, and finally dialyzed against distilled water for 7-8 days, and then freeze-drying the obtained upper layer dispersion to obtain graphene oxide; (2) weighing strontium nitrate, iron(III) nitrate nonahydrate, and neodymium(iii) nitrate, according to the stoichiometric ratio of the samarium-cobalt-doped barium ferrite chemical formula (Sr0.85Nd0.15Co0.15Fe11.85O19.3), dissolving calcium nitrate tetrahydrate in distilled water, and stirring to obtain a clear solution, slowly adding citric acid solution in dropwise manner, and adjusting the pH is to 7 after stirring to obtain the sol, and evaporating the sol in water bath at 75-85 degrees C, and stirring to obtain the wet gel, drying the wet gel, and then igniting in the air to obtain a fluffy precursor, grinding and calcining to obtain SNCF, (3) using graphene oxide and samarium-cobalt-doped barium ferrite in dimethylformamide respectively to obtain graphene oxide solution and samarium-cobalt-doped barium ferrite suspension is added to the graphene oxide solution, and adding into cetyltrimethylammonium bromide to the graphene oxide solution, after being uniformly dispersed, it is slowly adding to the samarium-cobalt-doped strontium ferrite suspension in dropwise manner, and mixing uniformly, then carrying out reaction, adding the hydrazine hydrate into the system, stirring in a 95 degrees C water bath for 12-14 hours, then suction filtering, washing with water, washing with alcohol until the filtrate is neutral, and finally vacuum drying to obtain a graphene/samarium cobalt doped barium ferrite composite; and (4) using the graphene/samarium-cobalt-doped strontium ferrite composite material and 1-2 ml aniline monomer dissolving in 30-50 ml of hydrochloric acid solution, the mol ratio of graphene/samarium-cobalt-doped strontium ferrite composite material to aniline is 1:2.5, and uniformly dispersing to obtain a dispersion; dissolving 2.5-3.5 g ammonium persulfate in 20-30 ml hydrochloric acid solution to obtain a transparent solution, which is slowly added dropwise to the above solution, stirring the dispersion in an ice water bath for 12-15 hours, and then subjecting to suction filtration, water washing, alcohol washing, and vacuum drying to obtain a graphene-based composite absorbing material.