▎ 摘　　要

NOVELTY - Preparing water-dispersible nano cuprous oxide/graphene composite powder comprises (i) ultrasonically dispersing graphite oxide, surfactant and copper salt in water to form a reaction solution at room temperature, where the concentration of graphite oxide is 0.5-1.5 mg/ml, mass ratio of surfactant and graphite oxide is 10:1:1, and copper salt to graphite oxide is 10:2:1, and (ii) adding reducing agent in a dropwise manner to reaction solution to obtain hydrazine hydrate solution, heating to 90-110 degrees C for 8-12 hours, cooling, filtering, collecting the filtrate, washing and drying. USE - The method is useful for preparing water-dispersible nano cuprous oxide/graphene composite powder. ADVANTAGE - The method is simple, economical and suitable for industrial production. The product has good dispersibility in water, excellent photocatalytic degradation ability of dye in the visible light with a wavelength of 500 nm and good photocatalytic killing ability of tumor cells, and is environmental friendly.