Enhanced degradation performance of organic dyes removal by bismuth vanadate-reduced graphene oxide composites under visible light radiation

As a photocatalyst, bismuth vanadate coupled with reduced oxide graphene (BiVO4-rGO) has been reported for dye degradation. However, this catalyst faced the disadvantages of low catalytic efficiency and long catalytic time. In this paper, BiVO4-rGO composites were synthesized by a modified hydrothermal method, and characterization results showed the monoclinic BiVO4 surface successfully coupled with a layer of rGO. The dye removal performance of BiVO4-rGO composites were evaluated by the degradation of malachite green and rhodamine B under visible light irradiation and photocatalytic results showed that the BiVO4 with rGO modification could effectively enhance the dyes removal performance. In a specific photocatalytic experiment, BiVO4-rGO-300 could remove 99.5% MG in two hours and 99.84% RhB in four hours, which was superior to previous studies. Furthermore, application of catalyst in practical wastewater was also taken into account. MG and RhB were degraded by BiVO4-rGO in several kinds of actual wastewater and experimental results showed that this catalyst could efficiently remove dye in actual environment. This improvement could be ascribed to the increase of special surface area, efficient charge transfer and reduction of electron-hole pair recombination with the incorporation of rGO. The influences of pH, supporting electrolyte and mechanism of the dye degradation were also investigated in details.