Acoustic levitation supplies a containerless state to eliminate natural convection and heterogeneous crystal nucleation and thus provides a highly uniform and ultra clean condition in the confined levitating area. Herein, we attempt to make full use of these advantages to fabricate well dispersed metal nanoparticles. The gold nanoparticles, synthesized in an acoustically levitated droplet, exhibited a smaller size and improved catalytic performance in 4-nitrophenol reduction were synthesized in an acoustically levitated droplet. The sound field was simulated to understand the impact of acoustic levitation on gold nanoparticle growth with the aid of crystal growth theory. Chemical reducing reactions in the acoustic levitated space trend to occur in a better dispersed state because the sound field supplies continuous vibration energy. The bubble movement and the cavitation effect accelerate the nucleation, decrease the size, and the internal flow inside levitated droplet probably inhibit the particle fusion in the growth stage. These factors lead to a reduction in particle size compared with the normal wet chemical synthetic condition. The resultant higher surface area and more numerous active catalytic sites contribute to the improvement of the catalytic performance.

声悬浮提供无容器状态以消除自然对流和异质晶体成核，从而在受限悬浮区域提供高度均匀和超清洁的条件。在此，我们试图充分利用这些优势来制造分散良好的金属纳米粒子。在声悬浮液滴中合成的金纳米颗粒在声悬浮液滴中合成时具有较小的尺寸和改进的 4-硝基苯酚还原催化性能。借助晶体生长理论模拟声场，了解声悬浮对金纳米颗粒生长的影响。声悬浮空间中的化学还原反应趋向于以更好的分散状态发生，因为声场提供了连续的振动能量。气泡运动和空化效应加速了形核，减小了尺寸，悬浮液滴内部的内部流动可能会抑制生长阶段的颗粒融合。与正常的湿化学合成条件相比，这些因素导致粒径减小。由此产生的更高的表面积和更多的活性催化位点有助于提高催化性能。