Architecting Bi2S3/graphene quantum dots/TiO2 photoelectrodes for aqueous Cr(VI)/methyl orange removal

Ternary shell/core/core Bi2S3/graphene quantum dots/TiO2 nanowire arrays (Bi2S3/GQDs/TNWs) photoelectrodes are constructed through electrophoretic deposition of GQDs onto TNWs followed by electrochemical deposition of Bi2S3 QDs. An interesting synergistic effect was observed in configuration of Bi2S3/GQDs/TNWs. Under irradiation, the photocurrent density of 50 μA/cm2 (an enhancement of ∼86%) and the removal efficiency of Cr (VI) is 97% (an enhancement of ∼76%) compared to that TiO2 nanowire array were obtained. Such significant enhancement is attributed to the strong photoabsorption ability of Bi2S3 QDs and excellent electron transport ability of GQDs.