The thin films of TiO_2, ZnO, Fe_2O_3 and heterojunction thin films of ZnO/TiO_2, Fe_2O_3/TiO_2 were prepared on quartz glass by dip-coating technique. The photocatalytic degradation of methylene blue on these films(λ=254 nm) showed that the photocatalytic activities of three films were in the following sequence: TiO_2>ZnO>Fe_2O_3, TiO_2/ZnO>TiO_2>TiO_2/Fe_2O_3. Compared with the films of pure ZnO and Fe_2O_3, heterojunction films of ZnO/TiO_2 and Fe_2O_3/TiO_2 had smaller contact angles, while Fe_2O_3/TiO_...