▎ 摘　　要

NOVELTY - Preparing a composite photocatalyst comprises (1) dissolving gadolinium oxide, ytterbium oxide and terbium oxide in concentrated nitric acid, completely reacting, adding a small amount of deionized water to form a rare earth nitrate solution, removing excess nitric acid in the solution, and placing in an oven, drying until it is completely dry, adding a citric acid monohydrate and ethylene glycol to the rare earth nitrate solution, stirring evenly, adding the orthoboric acid aqueous solution, forming homogeneous solution to remove water to form a dry gel, and performing calcination of the dry gel resin in a muffle furnace to obtain a white powder, (2) adding urea into the muffle furnace, increasing the temperature, maintaining the temperature for a period of time, cooling to room temperature to obtain the target compound graphene carbon nitride, and (3) dissolving sodium hydroxide and vanadium oxide in deionized water. USE - The method is useful for preparing a composite photocatalyst. ADVANTAGE - The method: is simple and environmentally friendly; has high yield; and saves energy. The composite photocatalyst has more efficient visible light response capability and photocatalytic performance. DETAILED DESCRIPTION - Preparing a composite photocatalyst comprises (1) dissolving of gadolinium oxide, ytterbium oxide and terbium oxide in concentrated nitric acid, completely reacting, adding a small amount of deionized water to form a rare earth nitrate solution, removing excess nitric acid in the solution, and placing in an oven, drying until it is completely dry, adding a citric acid monohydrate and ethylene glycol to the rare earth nitrate solution, stirring evenly, adding the orthoboric acid aqueous solution, forming homogeneous solution to remove water to form a dry gel, and performing calcination the dry gel resin in a muffle furnace to obtain a white powder, (2) adding urea into the muffle furnace, increasing the temperature, maintaining the temperature for a period of time, cooling to room temperature to obtain the target compound graphene carbon nitride, (3) dissolving sodium hydroxide and vanadium oxide in deionized water, keep stirring until completely dissolved to obtain a mixed solution, dissolving silver nitrate in deionized water, pouring the silver nitrate solution into the mixed solution, observing the yellow precipitate to generate, allowing to stand the precipitate, filtering, washing, and drying to obtain silver vanadium oxide, (4) mixing graphite carbon nitride and silver vanadate in proportions, adding absolute ethanol, stirring, ultrasonically cleaning and then drying to obtain silver vanadium oxide/graphitic carbon nitride composite photocatalyst, where the label is AC, (5) preparing sodium sulfide nonahydrate solution, configuring the AC composite photocatalyst, ultrasonically processing, slowly adding sodium sulfide nonahydrate solution to the AC composite photocatalyst, stirring in the dark, filtering, washing and drying to obtain silver vanadium oxide/graphitic carbon nitride/silver sulfide, where the label is ASC1, and (6) dissolving the up-down bidirectional conversion luminescent agent: ytterbium ion/ terbium ion nanoparticles in a absolute ethanol, stirring, dissolving, adding a ASC1, continuously stirring , ultrasonically mixing and then drying to obtain a composite photocatalyst.