CdSe Quantum Dots\nSupported on Sb<sub>2</sub>S<sub>3</sub> Nanorods as S‑Scheme\nHeterojunction Photoanode in\nPhotoelectrochemical Cells

The narrow bandgap semiconductor Sb<sub>2</sub>S<sub>3</sub> has\nbeen extensively utilized in solar cells for its impressive light\nabsorption coefficient and carrier mobility. However, a large number\nof deep energy defects provide carrier recombination sites that limit\nits photoelectrochemical (PEC) performance. In this study, Sb<sub>2</sub>S<sub>3</sub> nanorods (NRs) and CdSe quantum dots (QDs) were\nsuccessfully prepared, and Sb<sub>2</sub>S<sub>3</sub>/CdSe-annealed\nquasi-one-dimensional heterojunction photoanodes with the S-scheme\nwere constructed. The Sb<sub>2</sub>S<sub>3</sub>/CdSe-annealed composite\nphotoelectrode achieves a 12 times increase in photocurrent density\ncompared to the 0.4 mA cm<sup>–2</sup> of the Sb<sub>2</sub>S<sub>3</sub> photoelectrode. Overall, the synergistic effect of\nthe [hk1]-oriented Sb<sub>2</sub>S<sub>3</sub> NRs and the S-scheme\nheterojunction promotes carrier transport, achieving a spatial separation\nof photogenerated carriers and efficiently weakening the recombination\nof the electron–hole pair. This study provides a simple method\nfor the low-cost development of Sb<sub>2</sub>S<sub>3</sub> NRs with\n[hk1] orientation and an idea to enhance its development in the PEC\nwater splitting direction.