S‑Scheme Heterojunction\nEfficient Extraction\nof Hot Carriers in CsPbBr<sub>3</sub>/Bi<sub>4</sub>O<sub>5</sub>I<sub>2</sub> for Enhanced Photocatalytic H<sub>2</sub> Evolution and CO<su

This study investigates the photocatalytic capabilities\nof an S-scheme\nheterojunction formed by CsPbBr<sub>3</sub> and Bi<sub>4</sub>O<sub>5</sub>I<sub>2</sub> for H<sub>2</sub> evolution and CO<sub>2</sub> reduction. The heterojunction is designed to enhance the extraction\nof hot carriers and charge separation through interface engineering\nand an internal electric field. The initial <i>T</i><sub>c</sub> at higher pumping intensities indicates that CsPbBr<sub>3</sub> carriers injected into Bi<sub>4</sub>O<sub>5</sub>I<sub>2</sub> at\nhigher energies and temperatures cooled from 1800 to 800 K within\n200 fs after photoexcitation. Compared with CsPbBr<sub>3</sub>, CsPbBr<sub>3</sub>/Bi<sub>4</sub>O<sub>5</sub>I<sub>2</sub> showed substantial\nimprovement in photocatalytic H<sub>2</sub> production from 59.08\nto 1050.93 μmol h<sup>–1</sup> g<sup>–1</sup>.\nFurthermore, the S-scheme CsPbBr<sub>3</sub>/Bi<sub>4</sub>O<sub>5</sub>I<sub>2</sub> heterojunction displays outstanding photocatalytic\nCO<sub>2</sub> to CO performance, compared to pure CsPbBr<sub>3</sub>, from 2.84 to 83.6 μmol h<sup>–1</sup> g<sup>–1</sup>. These findings contribute to the understanding and development\nof S-scheme heterojunction extraction of hot carriers in perovskite\nmaterials for photocatalytic applications.