Contact‐Electro‐Catalysis Enables Ultrasonic Synthesis of Gold Nanoparticles at Water‐PTFE Interfaces

The synthesis of gold nanoparticles (AuNP) using sustainable methods remains a significant challenge in nanotechnology. Traditional approaches often rely on toxic chemicals or complex procedures, leading to unavoidable environmental concerns. In this study, we present a novel, environmentally friendly method for preparing AuNP via contact‐electro‐catalysis (CEC) driven by ultrasonication at the water‐dielectrics interfaces. This strategy eliminates the need for external chemical reducing agents, making it a sustainable alternative for nanoparticle production. Under ultrasonic stimulation at 40 kHz and 150 W, polytetrafluoroethylene (PTFE) transfers electrons to AuCl4− ions, effectively reducing them to elemental gold. The mean size of AuNP increased from 74 nm to 220 nm as ultrasonication duration extended from 1 to 20 min, highlighting the impact of contact duration on nanoparticle growth. A comparative study of dielectric materials, including Nylon‐6, polyvinylidene difluoride, and PTFE, reveals that PTFE with its higher electron affinity greatly outperforms other materials in facilitating the electron transfer necessary for the synthesis of AuNP. Additionally, the presence of H2O2 generated during the process also contributed to the reduction, further boosting AuNP synthesis. This study offers insights into the influence of dielectric materials on CEC efficiency, providing a promising, scalable, and green alternative for nanoparticle production.