Simultaneous Cr(VI) reduction and bisphenol A degradation by a 3D Z-scheme Bi2S3-BiVO4 graphene aerogel under visible light

Rational design strategy and facile synthesis method of photocatalysts with high efficiency and stability have been still a significant challenge for the removal of environmental contaminants. In this study, a three dimensional (3D) all-solid-state Z-scheme heterojunction photocatalytic system containing bismuth sulphide (Bi2S3) and bismuth vanadate (BiVO4) was constructed as Bi2S3-BiVO4 graphene aerogel (SVGA) by a facile hydrothermal method. The potential application of as-synthesized SVGA was demonstrated to remove Cr(VI) and bisphenol A (BPA) simultaneously in aqueous media via the synergy of adsorption and photocatalysis under visible light irradiation. The removal rates of Cr(VI) and BPA both nearly reached 100% after adsorption for 40 min and photocatalysis for 120 min under visible light (λ > 420 nm), which was much better than the removal efficiency of individual Bi2S3 and BiVO4, as well as Bi2S3 graphene aerogel (SGA) and BiVO4 graphene aerogel (VGA) samples. The rGO played an important role as photoinduced electron transfer mediator between Bi2S3 and BiVO4, which promoted the photogenerated electrons transfer efficiency and enhanced photocatalytic ability of SVGA efficiently. The harmful Cr(VI) was conserved into hypotoxic Cr(III) and BPA was degraded into CO2 and H2O after photocatalysis on SVGA, and the fabricated SVGA also presented favorable stability and satisfactory application effect in practical water samples, implied that such photocatalyst has a promising application for simultaneous removal of heavy metals and organics from aqueous environment.