Dual Polarization Field Synergistic in Bismuth‐Based S‐Scheme Heterojunction for Efficient Photocatalytic H ₂ O ₂ Generation

Enhancing charge separation is an effective strategy for promoting the efficiency of photocatalysts.Because photocatalysts possess both polarization electric fields and interfacial built‐in electric fields, they can provide stronger driving forces for photogenerated charge carriers, thereby suppressing their recombination. Therefore, designing heterojunction photocatalysts that simultaneously possess polarization and interfacial electric fields is promising for achieving highly efficient photocatalysis. However, because of the difficulty of overcoming van der Waals interactions and surface energy, producing heterojunctions with stable built‐in electric fields in ferroelectric photocatalytic devices is still a challenging issue. In this article, an in situ surface activation salting method is proposed for synthesizing a bismuth‐based ferroelectric heterojunction photocatalyst (Bi 4 NbO 8 Br/BiVO 4 ) that possesses stable bridging bonds. The synergistic effect of the dual‐polarized electric field and the built‐in electric field at the interface greatly enhanced the separation and migration efficiency of photogenerated charges. Moreover, the nanoscale BiVO 4 modification broadened the visible light absorption range of the catalyst. As a result, Bi 4 NbO 8 Br/BiVO 4 achieved highly efficient photocatalytic synthesis of H 2 O 2 about 492.75 µmol L −1 h −1 , demonstrating excellent performance among similar photocatalysts. This article provides a certain experimental basis for the template design and construction of efficient bismuth‐based photocatalytic materials for synthesizing H 2 O 2 through artificial photosynthesis.