Atomically dispersed Co sites on BiOCl nanosheets for efficient CO₂ photoreduction

Efficient CO₂ photoreduction to produce fuel remains a great challenge, due to the fast recombination of photogenerated charge carriers and the lack of effective reactive sites in the developed photocatalysts. Herein, single Co atoms (Co_SA) were highly dispersed on hydrothermally synthesized BiOCl nanosheets (BOC) by a facile two-step electrostatic self-assembly and pyrolysis method. The obtained Co_SA-BOC could be performed for efficient CO₂ photoreduction to stoichiometrically produce CO and O₂ at the ratio of 2:1, with the CO evolution rate reaching 45.93 μmol g⁻¹ h⁻¹, ∼4 times that of the pristine BOC. This distinctly improved photocatalytic performance for Co_SA-BOC should benefit from the introduction of atomically dispersed Co–O₄ coordination structures, which could accelerate the migration of photogenerated charge carriers to surface by creating an impurity energy level in the forbidden band, and act as the reactive sites to deliver the photogenerated electrons to activate CO₂ molecules for CO production. This work provides a facile and reliable strategy to highly disperse single atoms on low-dimensional semiconductors for efficient CO₂ photoreduction to selectively produce CO.