Enhancing photocatalytic CO2 reduction via constructing a tightly contacted Bi3O4Br/Bi2WO6 type-II heterojunction photocatalyst

Successful synthesis of Bi 3 O 4 Br/Bi 2 WO 6 type-II heterojunction photocatalyst. • Stability and CO₂ reduction activity of the as-prepared materials. • Bi 3 O 4 Br/Bi 2 WO 6 –20 exhibits best performance, achieving CO production rate of 13.73 μmol·g −1  h −1 . • Demonstration of closed junctional contact and synergistic effect of type-II heterojunction. The development of efficient, stable, and highly selective catalysts is of great importance for the photocatalytic reduction of CO 2 . However, the inefficient separation and transfer of photogenerated charge carriers remain a major challenge for Bi-based photocatalysts. In this work, Bi 3 O 4 Br/Bi 2 WO 6 type-II heterojunction photocatalyst via a two-step approach, and its photocatalytic CO 2 reduction performance was systematically investigated. The results shin that Bi 3 O 4 Br/Bi 2 WO 6 –20 exhibits best performance, achieving CO production rate of 13.73 μmol·g −1  h −1 and is approximately 2.09-fold compared with pure Bi 3 O 4 Br and 2.05 -fold compared with pure Bi 2 WO 6 , while maintaining nearly 100% CO selectivity. Based on the experimentally determined band structures and complementary spectroscopic and photoelectrochemical results, a possible type-II charge-transfer pathway is proposed to account for the enhanced CO 2 photoreduction performance. In addition, composite demonstrates excellent stability during photocatalytic process. This study provides an effective strategy for facile construction of efficient CO 2 reduction photocatalysts. Download: Download high-res image (176KB) Download: Download full-size image