Study On Synthesis Of Graphene-Bi₂MoO₆Composite Photocatalysts And The Photocatalytic Activity Of Graphene-Bi₂MoO₆under Visible Light Irradiation

Photocatalytic technology is an ideal environment treatment technology, which can make full use of the sunlight. It has many superiorities,such as low cost and non-pollution. In order to utilize solar energy, it is meaningful to find and research photocatalysts which have high photocatalytic activity under visible-light.The visible-light photocatalyst graphene-Bi2MoO6composite has been successfully synthesized using graphite oxide, Bi(NO3)3·5H2O and (NH4)6Mo7O24·4H2O through a simple hydrothermal process. The prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible diffuse reflectance spectroscopy (UV-vis DRS) and Brunauer-Emmet-Teller (BET) surface area analysis. It found that the mass percentage of graphite oxide, pH value of hydrothermal reaction system, hydrothermal temperature and hydrothermal holding time could affect the photocatalytic activity of the graphene-Bi2MoO6composite photocatalysts.The photocatalytic activity of the graphene-Bi2MoO6composite was investigated by the degradation of direct fast scarlet4BS in aqueous solution at room temperature under visible-light irradiation. It turned out that graphene-Bi2MoO6composite which was synthesized synthesized at140℃and pH0.6for8h with1.6wt%of graphite oxide showed the highest photocatalytic activity due to the good crystallization and high specific surface area. The surface area was11.5m2/g for the photocatalyst.Photocatalytic degradations of4BS were performed to investigate the influence of different conditions. The results showed that:The optimum composite dosage was0.25g/L when the initial strength of4BS was20mg/L, the decolorization ratio was91.5%; with initial concentration of4BS aqueous solution increasing from20mg/L to80mg/L, the decolorization ratio decreased; and graphene-Bi2MoO6composite photocatalysts exhibited efficient decolorization at strong acid and alkali condition,which showed high adsorptivity at strong acid condition and high photodegradation at strong alkali condition. The reuse experiments indicated that the structure of graphene-Bi2MoO6composite photocatalysts was stable after being used for five times, with high photocatalytic activity.The recovery efficiency of graphene-Bi2MoO6composite photocatalysts was improved.