Promoting selective dephosphorylation and aromatic nitroreduction by in-situ anchoring gold/silver bimetallic nanoparticles on ceria/polyethyleneimine nanosheets

Abstract

Addressing the dual challenges of phosphorus resource scarcity and organic pollutant treatment, this study develops a bifunctional ceria/polyethyleneimine/AuAg (CeO₂/PEI/AuAg) catalyst through self-assembly and in-situ reduction anchoring strategies for both efficient dephosphorylation and aromatic nitroreduction. Its components optimize the catalytic process through multilevel synergy: i) the oxygen vacancies in the CeO₂ component interact with H₂O to generate lots of protonated hydroxyl groups, which not only enhance the adsorption for phosphates but also facilitate continuous electron enrichment through the Ce³⁺/Ce⁴⁺ redox cycle, ii) the PEI component enhances the interfacial enrichment of phosphates, BH₄⁻, and p-nitrophenol through amino group protonation and serves as a green reductant to drive the in-situ uniform anchoring of AuAg bimetallic nanoparticles onto the CeO₂ support, iii) the AuAg bimetallic component directs the electrons enriched in CeO₂ oxygen vacancies and the reducing electrons provided by BH₄⁻ to dual reaction sites via strong metal-support interactions and hierarchical electron transfer channels, thereby improving reaction kinetics. Experimental results show that this catalyst achieves a 3.645 × 10⁻³ μmol g⁻¹ min⁻¹ dephosphorylation efficiency at 25 °C, with a 4.5 mol g⁻¹ min⁻¹ p-nitrophenol reduction rate (turnover frequency: 539 h⁻¹), outperforming most previously reported catalysts. This study provides a novel multifunctional material platform for sustainable phosphorus management and organic pollutant degradation.