▎ 摘　　要

NOVELTY - Preparing graphene-based photocomposite catalyst comprises e.g. (i) heating zirconium dioxide in a mixed gas atmosphere of nitrogen and ammonia, and cooling, (ii) calcining the nitrogen-doped zirconia in an N2 atmosphere at 400-500 degrees C for 4-6 hours, grinding, mixing the ground nitrogen-doped zirconia with 5-10 mol/l NaOH solution, heating, adding silver nitrate solution, reacting, cooling, filtering, drying, and finally calcining, (iii) grinding and dispersing the composite silver/nitrogen-doped zirconia in polyethylene glycol, and ultrasonicating, (iv) dispersing graphene into polyethylene glycol, adding the composite silver/nitrogen-doped zirconia suspension, ultrasonicating , centrifuging, washing and drying. USE - The photocomposite catalyst is useful for degrading organic pollutants in a water body (claimed). DETAILED DESCRIPTION - Preparing graphene-based photocomposite catalyst comprises (i) heating zirconium dioxide in a mixed gas atmosphere of nitrogen and ammonia at 950-1200 degrees C for 1-2 hours, and cooling to room temperature to obtain ZrO2-xNx type nitrogen-doped zirconia, (ii) calcining the nitrogen-doped zirconia in an N2 atmosphere at 400-500 degrees C for 4-6 hours, grinding, mixing the ground nitrogen-doped zirconia with 5-10 mol/l NaOH solution, heating and stirring at 150-180 degrees C for 1-2 hours, adding 5-10 mol/l silver nitrate solution, continuously reacting for 0.5-1 hour, cooling to room temperature, filtering, drying in an oxygen-free environment, and finally calcining the dried solid in a nitrogen atmosphere at 200-250 degrees C for 12-24 hours to obtain composite silver/nitrogen-doped zirconia, where the ratio of the nitrogen-doped zirconia to the sodium hydroxide solution is 0.3g: 20-40 ml, and the ratio of the amount of sodium hydroxide to silver nitrate is 1:1, (iii) grinding and dispersing the composite silver/nitrogen-doped zirconia in polyethylene glycol, ultrasonicating to obtain composite silver/nitrogen-doped zirconia suspension, where, the ratio of the composite silver/nitrogen-doped zirconia to polyethylene glycol is 0.01g: 100-200 ml, (iv) dispersing graphene into polyethylene glycol to obtain a polyethylene glycol suspension of graphene, adding the composite silver/nitrogen-doped zirconia suspension, ultrasonicating , centrifuging, washing, and drying, where the mass ratio of graphene to composite silver/nitrogen-doped zirconia is 0.5-1.2:100. An INDEPENDENT CLAIM is also included for graphene-based photocomposite catalyst is prepared by the above method.