Tuning the Active Sites of Atomically Thin Defective Bi₁₂O₁₇Cl₂ via Incorporation of Subnanometer Clusters

The introduction of subnanometer clusters as active sites on the surface of photocatalysts for efficiently tuning the selectivity and activity of the photocatalyts is still a challenge. Herein, the subnanometer Ag/AgCl clusters were incorporated on atomically thin defective Bi12O17Cl2 nanosheets via rebinding with unsaturated Cl atoms. Benefiting from the surficial Bi vacancies (VBi) and Bi–O vacancies (VBi–O) in this atomically thin architecture, the local atomic arrangement was tuned so that the subnanometer Ag/AgCl clusters were successfully incorporated. An enhancement of photocatalytic activity for NO removal was achieved in which the activity is 3 times higher than that of Bi12O17Cl2 and 1.8 times higher than that of defective Bi12O17Cl2. The substitution of the active sites from surficial VBi and VBi–O to be subnanometer Ag/AgCl clusters enables a tunable redox potential and different reaction mechanisms in NO removal. Moreover, the selectivity of the photoinduced redox reaction on NO oxidation and CO2 reduction was achieved via introducing an extra energy level.