Acoustic levitation synthesis and subsequent physicochemical properties of bimetallic composite nanoparticles

Bimetallic noble-metal nanoparticles were synthesized in a containerless state via acoustic levitation. We chose oleylamine as stabilizer and borane-t-butylamine complex as reducing agent to prepare the Au–Ag nanoparticles in organic phase. The synthesis process, particle size distribution, morphology, optical property, chemical composition, and catalytic performance of prepared bimetallic nanoparticles were characterized and analyzed. The Au–Ag nanoparticles synthesized in acoustic levitation exhibited a smaller size, narrower distribution range, and improved catalytic performance in 4-nitrophenol reduction compared with the normal container condition. In acoustic levitation, the catalytic activity of equiatomic Au–Ag nanoparticles was significantly enhanced due to synergistic effects.