Facet engineering of semiconductors for boosting photo-charge separation in solar fuel production

Photocatalysis promises green production of chemicals by using the inexhaustible solar energy, but the low photocatalytic activity of most semiconductors due to charge recombination remains a key barrier to their application. Recently, facet engineering of single semiconductor particles has emerged as an effective strategy to precisely tune the energetic structure, thereby lowering the charge recombination and enhance solar fuel production. Multiple approaches for facet engineering have been developed to construct efficient photocatalysts. In this review, the fundamental principles and the common facet-engineering approaches for improving the photo-charge separation and solar fuel production of semiconductors are summarized, focusing on how the various faceted particles modification strategies tune the inbuilt electric field and reaction kinetics. Additionally, the challenges and future trends in development of facet-engineered photocatalysts were discussed.