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.

利用太阳能将CO ₂转化为清洁燃料仍然受到光转化效率低的限制，异质结光催化剂被认为是解决这一问题的一种非常有效的方法。在此，通过一锅法离子热法制备了由赤铁矿（α-Fe ₂ O _{3 ）和碳氮化硼（BCN）组成的异质结系统。}α-Fe ₂ O ₃纳米颗粒在 BCN 纳米片表面原位生长，形成具有微量 α-Fe ₂ O ₃（小于 2 wt%）的 α-Fe ₂ O _{3 /BCN 异质结（FBCN）。}合成后的具有 1.46 wt% α-Fe ₂ O的 FBCN 催化剂₃在没有任何助催化剂或牺牲试剂的情况下提供最高的 CO ₂光还原活性（CO 为 55.1 µmol g ^-1），是纯 BCN 的 3.9 倍。增强的CO ₂还原活性可归因于高表面积和有效的界面接触异质结构，这赋予催化剂宽带可见光吸收、抑制光生电子空穴分离和促进电荷转移。同时，循环实验表明FBCN光催化剂具有良好的可重复使用性和稳定性。_{这项工作有助于设计和制备具有有效 CO 2}还原性能的 BCN 基异质结。