In situ synthesized α-Fe2O3/BCN heterojunction for promoting photocatalytic CO2 reduction performance

The conversion of CO2 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-Fe2O3) and boron carbonitride (BCN) was fabricated through a one-pot ionothermal method. α-Fe2O3 nanoparticles were grown in situ on the surface of BCN nanosheets, forming an α-Fe2O3/BCN heterojunction (FBCN) with tiny amounts of α-Fe2O3 (less than 2 wt%). The as-synthesized FBCN catalyst with 1.46 wt% α-Fe2O3 provides the highest CO2 photoreduction activity (55.1 µmol g-1 for CO) without any cocatalyst or sacrificial reagents, which is 3.9 times higher than that obtained for pure BCN. The enhanced CO2 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 CO2 reduction performance.