Defect and Carbon Coengineering of TiO ₂ Nanofibers for Highly Selective CO ₂ Photoreduction to CO

Constructing synergistic defect‐carbon couples on TiO ₂ nanofibers represents a promising yet challenging strategy for advancing photocatalytic CO ₂ reduction, as it enables simultaneous modulation of active sites and charge dynamics—key factors in achieving high activity and selectivity. Herein, we fabricate defect‐carbon‐coupled TiO ₂ nanofibers via a scalable electrospinning and reductive annealing method. The reductive annealing creates abundant oxygen vacancies, while the in situ generated graphitic carbon network serves as a highly conductive pathway, collectively improving charge separation and surface reactivity. The optimized catalyst exhibits a high CO evolution rate of 26.13 μmol·g ⁻¹ ·h ⁻¹ with ~89% selectivity in gas–solid CO ₂ photoreduction, along with excellent stability. In situ FTIR spectroscopy confirms the accelerated formation and accumulation of the key *COOH intermediate. DFT calculations further reveal that the defect–carbon coupling synergistically lowers the energy barrier for *COOH formation by 1.78 eV and effectively suppresses further hydrogenation toward CH ₄ . This work underscores the importance of dual defect–carbon engineering on TiO ₂ nanofibers as a versatile strategy for achieving efficient and selective solar‐driven CO ₂ conversion.