Single Metal of Silver Nanoparticles in the Microemulsion for Recyclable Catalysis of 4-Nitrophenol Reduction

Size control of silver nanoparticles (Ag NPs) to improve monodispersity and recyclability is crucial for application in nanocatalysts. Hence, a novel and effective protocol for in-situ synthesis of Ag NPs in the microemulsion was proposed. The surfactant-stabilized microcavity in microemulsion can provide a nanoscale reactor that limits nucleation, growth, and agglomeration of the particles. Ag NPs of 540-640 nm were successfully grown and exhibited excellent catalytic activity with the apparent rate constant (k) of 0.59 min -1 and the activation energy (Ea) of 23.03 kJ mol -1 toward the reduction of 4-nitrophenol. Moreover, the catalyst could be easily recycled and showed excellent reusability after 6 cycles. So, the silver nanoparticles can be extended to an important metalcatalyzed reduction in chemical industry, which is of great significance for the sustainable development.