Preparation of LaMnO3/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.

Graphical AbstractFE-SEM image and HRTEM image of LaMnO3/graphene (The morphology of the LaMnO3/graphene composite is shown in the figure. It shows that the perovskite nanoparticles are grown on the graphene sheets. The insert drawing is the HRTEM image of LaMnO3/graphene, in which the light gray is graphene, and the black spots are the LaMnO3 nanoparticles. Due to graphene's two-dimensional planar structure, the adsorptivity of dyes is improved compared to the bare LaMnO3. Because of its high conductivity, graphene can ensure holes and electron transfers fastly. Therefore, an effective charge separation can be achieved)Figure optionsDownload as PowerPoint slide