Engineering Co Single Atoms in Ultrathin BiOCl Nanosheets for Boosted CO₂ Photoreduction

Abstract Despite the development of a range of photocatalysts for CO 2 reduction, the practical applications are significantly limited by low conversion efficiencies and their reliance on sacrificial agents, which are rooted in thermodynamic and kinetic challenges related to CO 2 conversion. Here, the engineering of Co single atoms in ultrathin single‐crystal BiOCl nanosheets for boosted photocatalytic CO 2 reduction is reported. The engineering of Co atoms modulates the distribution of photogenerated charges at the catalyst surface, controlling key surface reaction dynamics and suppressing surface electron‐hole recombination. This modulation also improves light absorption and enhances CO 2 adsorption and activation, leading to more efficient surface reactions. Notably, CO 2 is stably adsorbed onto the (001) face of BiOCl through a Bi‐O‐C(= O)‐Co‐O coordination unit, which lowers the activation energy for CO 2 reduction and reduces the formation energy of COOH − intermediates. As a result, the BiOCl photocatalysts achieve a CO formation rate of 183.9 µmol g −1 h −1 , when irradiated with a 300 W Xe lamp without cocatalysts or sacrificial agents. It represents an ≈13‐fold increase compared to that of pristine BiOCl, and surpasses most reported Bi‐based photocatalysts to date. Current work provides valuable insights into engineering of single atoms for developing advanced CO 2 ‐reduction photocatalysts.