Design of 2D/1D Bi2MoO6/Bi19S27Br3 direct Z-scheme heterojunction with built-in internal electric field for enhanced CO2 photocatalytic reduction performance

Abstract

Bi-based heterojunctions have garnered extensive attention in photocatalytic carbon dioxide (CO2) reduction due to their efficient charge separation and strong redox ability. The built-in internal electric field (IEF) at the interface of the direct Z-scheme heterojunction interface serves as the driving force for charge transfer, however, suboptimal interfacial contact often restricts the carrier migration efficiency. Herein, we meticulously tune the contact interface over a Bi-based heterojunction by modulating the morphologies of the semiconductor components. Specifically, we synthesize a 2D/1D Bi2MoO6/Bi19S27Br3 (BMO/BSBr) direct Z-scheme heterostructure by embedding 1D BSBr nanorods onto 2D BMO nanosheets. Such a contact interface can optimize the photogenerated charge carrier migration across the BMO and BSBr, thereby significantly promoting their separation. As a result, the photocatalytic CO2 conversion performance of the optimized BMO/BSBr reaches 34.4 μmol g−1 h−1, exceeding those of BMO and BSBr by 4.5 and 19.8-folds, respectively. The mechanisms underlay this enhanced photocatalytic performance are revealed via in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), X-ray photoelectron spectroscopy and radicals trapping tests, showing that the internal electric field along with the fine-tuned contact interface hold the key for momentously boosting the photogenerated charge carrier utilization efficiency. This study provides a novel design strategy for constructing high-performance photocatalysts via chemical bonding interfacial, offering efficient charge transfer and high catalytic activity.