CdS/Bi2S3 heterojunction for boosted photocatalysis via synergistic H2O adsorption and charge separation

Simultaneously harnessing photogenerated electrons for water splitting (to produce H 2 ) and holes for benzyl alcohol oxidation (to synthesize high-value chemicals) offers a promising strategy to address the energy crisis. However, charge rapid carrier recombination and weak H 2 O adsorption capacity severely limit the efficiency of this approach. Herein, we employ electrostatic self-assembly to construct a CdS/Bi 2 S 3 composite photocatalyst featuring an S-scheme electron migration pathway and a robust built-in electric field (BEF). This work demonstrates that the strong BEF of the CdS/Bi 2 S 3 composite photocatalyst significantly enhances the chemisorption capacity of H 2 O molecules and the carrier separation efficiency. The optimal CdS/Bi 2 S 3 -3 composite achieves H 2 and benzaldehyde production rates of 17.9 and 16.1 mmol g −1  h −1 , respectively. Comprehensive characterization and theoretical calculations elucidate the mechanisms underlying the S-scheme electron transfer pathway and the formation of the BEF. This study offers a new perspective for designing photocatalytic systems that simultaneously utilizing photogenerated electrons and holes.