Unprecedented Wall‐Atomically Thick Bi ₅ O ₇ Br Nanotubes Embedding Abundant Bi Nanodots Boosting Efficiently Photothermal Coupling Catalytic CO ₂ Conversion

ABSTRACT Unprecedented wall‐atomically thick Bi 5 O 7 Br nanotubes (NTs) embedding abundant Bi nanodots (NDs) were synthesized. A rolling‐up and following in situ reduction process was proposed for the formation mechanism of the Bi@Bi 5 O 7 Br. This unique nanostructure displays encouraging performance for photocatalytic CO 2 reduction into CO yield of 95.1 μmol·g −1 for the first hour with light illumination at ambient temperature in the presence of water vapor, 13.5‐time enhancement relative to bulk Bi 5 O 7 Br. With synergistic effect of light and auxiliary heat, Bi@Bi 5 O 7 Br shows the CO production as high as 1.3 mmol·g −1 at the first hour at 160°C, and 13.7 times of that with only light illumination. Such remarkable performance enhancement clearly demonstrates the strong photothermal synergy between solar light and mild thermal field. Implanting thermal field proves to allow the photo‐excited electrons to be heated to high‐energy states, through which these hot electrons can cross the Schottky barrier via quantum tunneling effect and efficiently transfer from Bi 5 O 7 Br NTs to Bi NDs as electron traps, improving the separation ability of electron‐hole pairs. The atomic thickness of Bi 5 O 7 Br NTs also enables the photo‐excited carriers to easily transfer from the interior to the surface with shortened charge transfer distance, improving utilization rate of carriers.