In situ synthesized α-FeO/BCN heterojunction for promoting photocatalytic CO reduction performance.

The conversion of CO into clean fuels by utilizing solar energy is still limited by a low photoconversion efficiency, and heterojunction photocatalysts are considered a very effective way to solve this problem. Herein, a heterojunction system consisting of hematite (α-FeO) and boron carbonitride (BCN) was fabricated through a one-pot ionothermal method. α-FeO nanoparticles were grown in situ on the surface of BCN nanosheets, forming an α-FeO/BCN heterojunction (FBCN) with tiny amounts of α-FeO (less than 2 wt%). The as-synthesized FBCN catalyst with 1.46 wt% α-FeO provides the highest CO photoreduction activity (55.1 µmol g for CO) without any cocatalyst or sacrificial reagents, which is 3.9 times higher than that obtained for pure BCN. The enhanced CO reduction activity can be attributed to the high surface area and effective interface-contacted heterostructure, which endows the catalyst with broadband visible light absorption, suppressed separation of photogenerated electron holes, and promoted charge transfer. Meanwhile, cycling experiments demonstrate that the FBCN photocatalyst shows good reusability and stability. This work can assist in the design and preparation of BCN-based heterojunctions with effective CO reduction performance.