Abstract: The use of the internal magnetic field of ferromagnets can effectively promote charge separation and transfer (CST) in photoelectrochemical energy conversion. However, photoelectrochemical materials with a ferromagnetic field are scarce, and the internal magnetic field is negligible in nonferromagnetic materials. To address this issue, we propose a rational method for preparing ferromagnetic TiO₂ powder using controllable oxygen vacancies in anatase TiO₂ with co-exposed {001} and {101} facets. Accordingly, an excellent saturation magnetisation of 0.0014 emu/g in TiO₂ is achieved owing to an asymmetric and uneven charge distribution. Compared with that of nonferromagnetic TiO₂, the efficiency of photocatalytic hydrogen generation of ferromagnetic TiO₂ is improved by 0.64 times. The enhancement of photocatalytic hydrogen generation is due to the different forces exerted on the electrons and holes in the magnetic field, which significantly improve the photogenerated CST efficiency of ferromagnetic TiO₂. This result highlights the significant role of the synergistic regulation of the crystal structure and defects in regulating the ferromagnetic characteristics of materials. The findings of this study provide guidance for leveraging point defects to promote CST for high-efficiency solar-energy conversion systems.

Key words: Photocatalysis, TiO₂ {001}-{101} surface heterojunctions, Oxygen vacancies, Ferromagnetic