Engineering BiVO4@Bi2S3 heterojunction by cosharing bismuth atoms toward boosted photocatalytic Cr(VI) reduction.

The photocatalytic efficiency is limited by poor charge separation efficiency and high carrier transport activation energy (CTAE) of photogenerated electron/hole pairs than traditional semiconductor. Hybridizing nanostructure with two staggered alignment band structure is proved as an effective strategy to mitigate these two challenges but still suffers a strong coulomb electrostatic repulsive force between two heterogeneous semiconductors. Here, we steer a friendly sulfurization process to construct BiVO 4 @Bi 2 S 3 heterojunction with a scenario of cosharing Bi atoms. The intimate atomic-level contact between BiVO 4 and Bi 2 S 3 not only enhances the visible-light absorption and lowers CTAE, but also accelerate carrier's separation efficiency, which enables it to deliver the best photocatalytic performance toward reduction of Cr(VI). BiVO 4 @Bi 2 S 3 only needs less than 40 min to completely reduce 50 ppm Cr(VI) solution. The type II heterojunction photocatalytic mechanism is systematically studied to decipher the carriers' transfer track between BiVO 4 and Bi 2 S 3. Our new finding of engineering inorganic heterojunction by cosharing atoms opens a new avenue to other similar materials for potential applications. ga1 • An in situ sulfurization method is proposed to engineer atomic-level BiVO 4 @Bi 2 S 3 heterojunction. • BiVO 4 @Bi 2 S 3 possesses enhanced visible light absorption, and exhibits faster exciton dissociation efficiency. • The CTAE of photogenerated electron/hole pairs was greatly reduced at BiVO 4 @Bi 2 S 3 compared to undecorated BiVO 4. • The photocatalytic Cr(VI) reduction rate of BiVO 4 @Bi 2 S 3 heterojunction is 35.5 times higher than that of BiVO 4. [ABSTRACT FROM AUTHOR]