S-scheme heterojunction AgCl/g-C3N4 with a unique electron transfer channel via a built-in electric field for enhanced H2 production

Abstract

The polyunsaturated edge Ag in a surface-modified catalyst plays a prominent role in the accumulation of electrons during photocatalytic H₂ production. Nevertheless, a moderate and straightforward method for efficiently baring edge Ag is still a grand challenge. Herein, cubic phase AgCl is prepared as an effective cocatalyst to modify the surface of g-C₃N₄, which restricts the agglomeration between g-C₃N₄ layers and results in efficient and sustainable photocatalytic H₂ production. The supreme AgCl/g-C₃N₄ catalyst realizes a H₂ evolution of 120.39 μmol in 4 h and good sustainability. The lifetime of photoexcited electrons in g-C₃N₄ is effectively prolonged within the S-scheme heterojunction. In addition, AgCl supplies extensive polyunsaturated edges of Ag as active sites. Meanwhile, the N₂ TPD data shows that chemisorption of H₂O abates dissociation energy for H₂O splitting, hence promoting H₂ production performance. This study emphasizes the importance of a built-in electric field and a unique electron transfer channel for improving electron utilization of AgCl/g-C₃N₄ to strengthen the H₂ evolution activity.