Synergistic surface charge channel and oxygen vacancy engineering in Sillén–Aurivillius Bi7Fe2Ti2O17Cl oxyhalides using in situ Ag clusters for boosting photocatalytic activity

Abstract

Bi-based Sillén–Aurivillius oxyhalides have attracted extensive attention from researchers owning to their wide range of light absorption, appropriate band structure, and excellent stability; however, their practical application is still limited by their rapid charge recombination. Herein, silver (Ag)-cluster-decorated novel Sillén–Aurivillius oxyhalides (bismuth iron titanium oxyhalide (Bi₇Fe₂Ti₂O₁₇Cl)) with abundant oxygen vacancies (OVs), were successfully synthesized to achieve efficient light absorption and interfacial charge separation. The optimal Ag/Bi₇Fe₂Ti₂O₁₇Cl composites showed excellent tetracycline hydrochloride (TCH) degradation and CO₂ reduction efficiencies. The theoretical and experimental results demonstrate that the superior activity is primarily due to the increased magnetic moment of Bi₇Fe₂Ti₂O₁₇Cl induced by the interactions between Ag and O atoms, which strengthens the built-in electric field at the Schottky junction interface and promotes the transfer of photogenerated electrons from Ag clusters to oxyhalides, thus enhancing the generation of charge carriers in the semiconductor and inhibiting bulk recombination. Simultaneously, the synergistic effects of the thermodynamics and kinetics of photocatalytic CO₂ reaction along with a lower Gibbs free energy are also responsible for the outstanding CO generation process. This work emphasizes the promising role of metal clusters as co-catalysts in the field of photocatalysis.