Bi₂Fe₄O₉@ZnIn₂S₄ S-scheme laminated heterojunction photocatalyst towards optimized photocatalytic performance

Reasonable design of heterojunction photocatalysts can effectively promote charge separation, thus improving their photocatalytic performance. Herein, a Bi₂Fe₄O₉@ZnIn₂S₄ S-scheme laminated heterojunction photocatalyst with 2D/2D interface interaction is prepared via a hydrothermal-annealing-hydrothermal method. The photocatalytic hydrogen production rate of Bi₂Fe₄O₉@ZnIn₂S₄ is up to 3964.26 μmol h^-1 g^-1, which is 12.1 times higher than that of pristine ZnIn₂S₄. In addition, its photocatalytic tetracycline degradation efficiency (99.9%) is also optimized. The enhanced photocatalytic performance can be attributed to the formation of S-scheme laminated heterojunctions that facilitate charge separation as well as strong 2D/2D laminated interface interactions favoring charge transfer. By combining in situ irradiation X-ray photoelectron spectroscopy with other characterization methods, the photoexcited charge transfer mechanism of S-scheme heterojunctions has been proved. Photoelectric chemical tests demonstrate the effectiveness of the S-scheme laminated heterojunction in improving the charge separation. This strategy provides a novel perspective for designing other high-efficient S-scheme laminated heterojunction photocatalysts.