The use of Mimosa pudica flower extract in the synthesis of highly stable gold nanoparticles (AuNPs) is reported here. On treatment of aqueous chloroauric acid with crude aqueous extract of Mimosa pudica flowers, rapid reduction of Au³⁺ ions at room temperature was observed without the need of any additional reducing or stabilizing agent. The synthesized AuNPs were characterized by UV–Vis spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS) and Zeta potential, X-Ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR) spectroscopy. UV-Vis studies indicated the formation of AuNPs. The AuNPs were almost spherical in shape with an average particle size of 24 nm as determined by FESEM, TEM and DLS particle size analysis. XRD studies and high resolution TEM images ascertained the crystalline nature of the AuNPs. FTIR analysis of flower extract and AuNPs showed the possibility of phenolic group as responsible for the reduction of Au³⁺. The stability of the AuNPs was analyzed by Zeta potential measurements. A negative Zeta potential value of -33.4 mV proved the stability of the AuNPs. The as synthesized AuNPs exhibited good catalytic activity in the model reduction reaction of 4-Nitrophenol to 4-Aminophenol.

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