▎ 摘　　要

NOVELTY - Nano-photocatalytic composite material comprises reduced graphene oxide and rare-earth ion-doped titanium dioxide nanoparticles, where the nanoparticles are uniformly distributed in both sides of the reduced graphene oxide sheet, the molar ratio of titanium dioxide and rare earth ions is 1:(0.0005-0.30), preferably 1:(0.005-0.02), and the mass ratio of rare earth ion doped titanium dioxide nanoparticles and reduced graphene oxide is 1:(0.0005-0.4), preferably 1:(0.002-0.02). USE - The nano-photocatalytic composite material is used for air purification, preferably degradation of volatile organic substance (claimed). ADVANTAGE - The nano-photocatalytic composite material can efficiently and stably remove low-concentration and flowing gas-phase volatile organic compounds, so as to effectively purify the air. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the composite nano-photocatalytic composite material, which involves (i) dispersing titanium source in an alcohol solvent to obtain a mixed solution, (ii) adding rare earth source and acid solvent to the mixed solution obtained in step (i), and stirring at ambient temperature until a sol is obtained, (iii) aging the sol in air to obtain a gel, and calcining and grinding the gel to obtain a rare earth-doped titanium dioxide nanopowder, (iv) dispersing the rare earth-doped titanium dioxide nanopowder in an alcohol/water mixed solvent and adding graphene to obtain a suspension, (v) adding a pH regulator to the suspension, stirring and washing at ambient temperature to obtain a composite nanopowder, and (v) calcining the composite nano powder to obtain a nano-photocatalytic composite material.