Titanium dioxide composite nanoparticles as well as preparation method and application thereof

The invention discloses titanium dioxide composite nanoparticles as well as a preparation method and application thereof, and relates to the technical field of photocatalytic materials. The preparation method of the titanium dioxide composite nanoparticles comprises the following steps: S1, heating a first solution to 85-95 DEG C, and then adding a second solution into the first solution to obtain a third solution; s2, aging after the third solution is naturally cooled to room temperature, and then removing impurities, washing and drying to obtain an intermediate product; s3, calcining the intermediate product to obtain titanium dioxide composite nanoparticles; wherein in S1, the first solution comprises a metal salt, a titanium dioxide precursor and an organic solvent; the second solution comprises urea and water; the metal salt is mixed salt of ferric salt and lanthanum salt, and/or zinc salt. The titanium dioxide composite nanoparticles prepared by the method disclosed by the invention are more uniform in