Preparation of La MnO_3/graphene thin films and their photocatalytic activity

A novel photocatalyst of LaMnO₃/graphene thin films with the perovskite-type was synthesized by sol-gel process assisted with spin-coating methods on glass substrates. The prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brumauer-Emmett-Teller (BET) surface area analyzer, X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy. Results showed that after the introduction of graphene, the perovskite structure was unchanged and the size of LaMnO₃ particles was about 22 nm, which uniformed growth in graphene sheet. Determination of contact angle indicated that the contact angle of glass substrate decreased and the hydrophilicity improved after treating with H₂SO₄ and APTES. The UV-Vis photocatalytic activity of the photocatalysts was evaluated by the degradation of diamine green B. LaMnO₃/graphene thin films had better photocatalytic ability than LaMnO₃ and TiO₂ films. The obtained k was 0.5627 and 0.3441 h^?1 corresponding to LaMnO₃/graphene films and TiO₂ films, respectively.