Facile Synthesis of AuPt Alloy Nanoparticles in Polyelectrolyte Multilayers with Enhanced Catalytic Activity for Reduction of 4‑Nitrophenol

In this work, bimetallic AuPt alloy nanoparticles were synthesized <i>in situ</i> in polyelectrolyte multilayers (PEMs) via an ion-exchange and coreduction process, in which the PEM support also served to suppress the Au–Pt phase separation, and thus enabled formation of AuPt alloy nanoparticles over a wide composition range. The PEM supported AuPt alloy nanoparticles exhibited higher catalytic activity than Au and Pt monometallic ones for the reduction of 4-nitrophenol by NaBH₄, showing synergistic effects between Au and Pt. This work provides a facile approach to <i>in situ</i> synthesis of polymer supported bimetallic nanoparticles of tailored composition for optimum performance in catalysis and other applications