▎ 摘　　要

NOVELTY - Preparation of graphene photothermal conversion material involves placing 3-5 pts. wt. sodium nitrate, 4-6 pts. wt. flake graphite and 180-220 pts. wt. concentrated sulfuric acid in the reactor, stirring for 50-70 minutes, adding 40-45 g potassium permanganate, reacting at 15-20 degrees C for 3-4 hours, adding dilute sulfuric acid and sodium hydroxide solution and continuously stirring until free of bubbles. USE - Method for preparing graphene photothermal conversion material. ADVANTAGE - The method is energy-saving, environment-friendly, safe, simple and fast; and does not produce harmful substances. DETAILED DESCRIPTION - Preparation of graphene photothermal conversion material comprises: (A) placing 3-5 pts. wt. sodium nitrate, 4-6 pts. wt. flake graphite and 180-220 pts. wt. concentrated sulfuric acid in the reactor, stirring for 50-70 minutes, adding 40-45 g potassium permanganate, reacting at 15-20 degrees C for 3-4 hours, adding dilute sulfuric acid and sodium hydroxide solution and continuously stirring until free of bubbles; (B) taking khaki-colored solution and washing with dilute sulfuric acid and deionized water to neutrality; (C) ultrasonically crushing for greater than or equal to 2.5 hours to ensure complete stripping of graphene; (D) centrifuging to remove the graphene that has not been completely stripped with rotation speed of not lower than 12000 revolutions/minute and taking graphene oxide left in the supernatant; (E) mixing upper layer containing graphene oxide with ferrous sulfate and iron chloride where graphene oxide is used as carrier which forms iron oxide nanoparticle layer on its surface; (F) adding poly(N-isopropylacrylamide) hydrogel and stirring to obtain graphene hydrogel composite material containing iron oxide; and (G) inspecting by scanning electron microscopy and transmission electron microscopy and performing line characterization to obtain composite nanoparticles with particle size of 110-120 nm.