Reduction of CO₂ to solar fuels by artificial photosynthesis technology has attracted considerable attention. However, insufficient separation of charge carriers and weak CO₂ adsorption hamper the photocatalytic CO₂ reduction activity. Herein, we tackle these challenges by introducing oxygen vacancies (OVs) on the two-dimensional Bi₄Ti₃O₁₂ ultrathin nanosheets via a combined hydrothermal and post-reduction process. Selective photodeposition experiment of Pt over Bi₄Ti₃O₁₂ discloses that the ultrathin structure shortens the migration distance of photo-induced electrons from bulk to the surface, benefiting the fast participation in the CO₂ reduction reaction. The introduction of OVs on ultrathin Bi₄Ti₃O₁₂ nanosheets leads to enormous amelioration on surface state and electronic structure, thereby resulting in enhanced CO₂ adsorption, photoabsorption and charge separation efficiency. The photocatalytic experiments uncover that ultrathin Bi₄Ti₃O₁₂ nanosheets with OVs reveal a largely enhanced CO₂ photoreduction activity for producing CO with a rate of 11.7 μmol g⁻¹ h⁻¹ in the gas–solid system, ~3.2 times higher than that of bulk Bi₄Ti₃O₁₂. This work not only yields efficient ultrathin photocatalysts with OVs, but also furthers our understanding on enhancing CO₂ reduction via cooperative tactics.

通过人工光合作用技术将CO ₂还原为太阳能燃料已经引起了广泛的关注。然而，电荷载流子的分离不充分和弱的CO ₂吸附妨碍了光催化的CO ₂还原活性。在这里，我们通过结合水热和后还原工艺在二维Bi ₄ Ti ₃ O ₁₂超薄纳米片上引入氧空位（OVs）来解决这些挑战。Bi ₄ Ti ₃ O ₁₂上Pt的选择性光沉积实验美国专利No.5,864,837公开了超薄结构缩短了光致电子从块体到表面的迁移距离，有利于快速参与CO ₂还原反应。在超薄Bi ₄ Ti ₃ O ₁₂纳米片上引入OV可以极大改善表面态和电子结构，从而提高CO _2的吸附，光吸收和电荷分离效率。光催化实验发现，具有OVs的超薄Bi ₄ Ti ₃ O ₁₂纳米片显示出以11.7μmolg的速率生产CO的CO _2光还原活性大大增强。在气固系统中^-1 h ^-1，比块状Bi ₄ Ti ₃ O ₁₂高约3.2倍。这项工作不仅可以生产出具有OVs的高效超薄光催化剂，而且进一步增进了我们对通过合作策略提高CO ₂还原的认识。