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Visible-light-active photoelectrodes are more responsive to high-energy conversion efficiency in photoelectrochemical (PEC) water splitting. In this work, we fabricated a bismuth sulfide@reduced graphene oxide (Bi2S3@rGO) nanocomposite photoanode via facile synthetic methods. Typical results show that the Bi2S3@rGO nanocomposite exhibited a high photocurrent density of 6.06 mA cm–2 and a maximum applied bias photon-to-current efficiency (ABPE) of 4.2% at 0.32 V. Moreover, Bi2S3 nanorods have more uniform dispersion on the surface of rGO sheets in the Bi2S3@rGO composite as demonstrated in the transmission electron microscopy images. In addition, photoluminescence and impedance studies reveal the enhanced charge-transfer properties in the Bi2S3@rGO photoelectrode. The enhanced PEC performance of the composite could be attributed to the effective visible-light absorption of Bi2S3 and the good electron-transfer properties of highly conductive rGO nanosheets, facilitating the charge separation and transportation, leading to the inhibition of charge recombination.

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The development of efficient and novel p-n heterojunctions for photoelectrochemical (PEC) water splitting is still a challenging problem. We have demonstrated the complementary nature of (p-type) BiSbS3 as a sensitizer when coupled with (n-type) TiO2/CdS to improve the photocatalytic activity and solar to hydrogen conversion efficiency. The as-prepared p-n heterojunction TiO2/CdS/BiSbS3 exhibits good visible light harvesting capacity and high charge separation over the binary heterojunction, which are confirmed by photoluminescence (PL) and electrical impedance spectroscopy (EIS). The ternary heterojunction produces higher H2 than the binary systems TiO2/CdS and TiO2/BiSbS3. This ternary heterojunction system displayed the highest photocurrent density of 5 mA·cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE) in neutral conditions, and STH of 3.8% at 0.52 V vs. RHE is observed. The improved photocatalytic response was due to the favorable energy band positions of CdS and BiSbS3. This study highlights the p-n junction made up of TiO2/CdS/BiSbS3, which promises efficient charge formation, separation, and suppression of charge recombination for improved PEC water splitting efficiency. Further, no appreciable loss of activity was observed for the photoanode over 2500 s. Band alignment and interfaces mechanisms have been studied as well.