In situ polymerization-induced confined aggregation of poly(ionic liquid)-BiOBr nanosheets for enhanced photocatalytic activity.

Two-dimensional semiconductor nanosheets represent a kind of promising photocatalysts for environmental improvement and clean production, however, insufficient interface defects and weak built-in electric field limit resultful electron-hole separation and photocatalytic performance. Herein, we propose a novel strategy involving in situ confined aggregation of bismuth oxybromide (BiOBr) using poly (ionic liquid) (PIL) networks. By employing a bromine-containing imidazolium ionic liquid as both Br source and monomer, PIL networks confined defective BiOBr composite (BiOBr-PIL) is synthesized through in situ polymerization that spatially restricts the aggregation of BiOBr nanosheets. At the optimal Bi/VBImBr ratio of 1:3, the positively charged PIL layer around BiOBr nanosheets establishes a built-in electric field and induces the electrostatic repulsion, effectively suppressing nanosheet aggregation and promoting the formation of oxygen vacancies. These features collectively enhance charge separation and accelerate reactive radicals production, leading to significantly improved photocatalytic activity in both tetracycline degradation and CO2 photoreduction, coupled with excellent stability and practical application potential.