Synthesis of Bi₂Fe₄O₉/reduced graphene oxide composite by one-step hydrothermal method and its high photocatalytic performance

Visible-light-driven degraded organic pollutant with high efficiency is crucial in the current photocatalysis research. A new kind composite photocatalyst with high visible-light photocatalytic activity which consists of Bi₂Fe₄O₉ and reduced graphene oxide (RGO) has been synthesized through one-step hydrothermal method at low temperature. Pure Bi₂Fe₄O₉ was formed with the addition of graphene oxide (GO) when the concentration of NaOH is 12 mol/L (M) at 180 °C for 72 h hydrothermal reaction. At the same time, the GO was reduced to RGO and adsorbed on the surface of Bi₂Fe₄O₉. The resultant composite photocatalyst showed higher absorption not only in the UV range but also in the visible light than pure Bi₂Fe₄O₉ indicating more electron–hole pairs generated. The band gap of photocatalysis was reduced from 1.91 to 1.69 eV and recombination of photo-generated electron–hole pairs in composites were decreased through marrying RGO with Bi₂Fe₄O₉. As a result, the Bi₂Fe₄O₉/RGO composite photocatalyst displayed higher catalytic activity for the degradation of methyl violet under visible light irradiation than rare Bi₂Fe₄O₉, promising the use of the Bi₂Fe₄O₉/RGO composite in visible-light photocatalysis.