Three birds with one stone: A piezo-photocatalytic system for synergistic environmental remediation through simultaneous ionic liquids degradation, H2 production, and uranium reduction

Ionic liquids (ILs) have emerged as new persistent pollutants in aquatic environments due to their notable ecotoxicity. Herein, In2Se3@Ag3PO4 S-scheme piezo-photocatalyst with interfacial In-O and Se-P covalent bonds is prepared for efficient degradation of 1-butyl-2,3-dimethylimidazole bromide ([BMMIm]Br). The experimental results demonstrate that 98.3 % of [BMMIm]Br is degraded under piezo-photocatalysis. Notably, [BMMIm]Br functions as a hole sacrificial agent, leading to a simultaneous H2 production rate of 582.7 mu mol g-1 h-1 and a co-removal efficiency of 97.2 % for radioactive heavy metal ions of U(VI), achieving the "three birds with one stone" effect. Density functional theory (DFT) calculations indicate that the S-scheme structure, combined with the In-O and Se-P covalent bonds and the piezoelectric effect, effectively promotes the separation of electron/hole pairs while inhibiting carrier recombination dynamics, thereby enhancing piezo-photocatalytic performance. Moreover, systemic toxicity evaluations, including assessments of calculated toxicity, zebrafish growth, and bean sprout development, were conducted to verify the reduced toxicity of the degraded intermediates, highlighting the potential practical applications of this approach.