▎ 摘　　要

NOVELTY - Photocatalyst comprises graphene oxide supported nickel-doped titanium dioxide. USE - The photocatalyst is useful for treating water (claimed). ADVANTAGE - The photocatalyst has high efficiency under visible light wavelength. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) producing photocatalyst, comprising (a) preparing doped titanium dioxide supported graphene oxide from dispersion solution containing oxidized graphene oxide and nickel-doped titanium dioxide, and (b) heating; (2) treating water, comprising (i) absorbing organic compound from aqueous solution by subjecting the photocatalyst, and (ii) performing photolysis by irradiating light having wavelength of 200-800 nm; and (3) water treating device comprising an injection portion for injecting aqueous solution containing organic compound, a filtration portion provided with the photocatalyst for adsorbing organic compound, an outlet for discharging the aqueous solution, and a lamp for irradiating light to the filtration portion.