In-situ synthesis of Au/sulfonated electroactive polyimide nanocomposites and their application on catalytic reduction of 4-nitrophenol

Nanocomposites have been applied in the field of heterogeneous water pollution, where their efficiency in degrading organic pollutants is primarily attributed to the synergistic effects and interfacial interactions among nanomaterials. In this research, a facile strategy was employed to synthesize Au/sulfonated electroactive polyimide nanocomposites. Utilizing the in-situ redox activity of the electroactive structure, Au ions were directly reduced into Au nanoparticles (AuNPs) without need for additional reducing agents. Notably, the segmental structure of the electroactive polymer was modulated by varying the dianhydride precursors, thereby tuning the proportion of electroactive units and the coordination capacity of sulfonated groups, which in turn affected the anchoring efficiency of AuNPs and their catalytic activity toward 4-nitrophenol (4-NP) reduction. The nanocomposites were systematically characterized by FTIR, TGA, XRD, XPS, SEM, TEM and CV to confirm their surface chemical structures and properties. Catalytic performance was evaluated using UV–Vis spectroscopy with NaBH 4 as the hydrogen donor. The results revealed that Au/S-PEPI could completely reduce 4-NP to 4-aminophenol (4-AP) within 13 min, with a pseudo-first-order rate constant of 1.6 × 10 −3 s −1 . Based on ten consecutive cycles, the conversion efficiency remained 98%. This demonstrates that the nanocomposites possess excellent catalytic activity and outstanding reusability and highlights their potential for applications in water remediation.