In this chapter, an environment‐friendly approach in synthesizing Au and Au@Ag metal nanoparticles using a microgel is demonstrated. Poly(N‐isopropyl acrylamide)/polyethyleneimine microgel was used as a multifunctional template to reduce metal ions to metal nanoparticles, stabilize and immobilize these metal nanoparticles, and regulate their accessibility within the template. Such multifunctional roles of microgel template were possible due to their unique properties (i.e., amino groups reducing capability, electrostatic and steric stabilizing properties, and swelling/deswelling properties). Characterizations of these metal/polymeric composite particles were also performed, such as scanning electron microscope (SEM), transmission electron microscope (TEM), Zeta‐potential, UV‐vis spectroscopy, X-ray Diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS). To test the catalytic activities of both gold and gold@silver nanoparticles in the microgel template, a model reaction (i.e., reduction of p‐nitrophenol to p‐aminophenol) was performed. Results showed that bimetallic gold@silver gave 10 times higher catalytic activity compared to monometallic gold nanoparticles. With the simple one‐step synthesis, a highly scalable process is possible.
Part of the book: Green Chemical