In situ green synthesis of Ag nanoparticles on tea polyphenols-modified graphene and their catalytic reduction activity of 4-nitrophenol.

In this work, a complete green synthesis approach to reduced graphene oxide-Ag nanoparticles hybrid by using tea polyphenol as both reducing and stabilizing agent is reported. On the one hand, tea polyphenols can efficiently reduce graphene oxide and adsorb on the surface of the reduced graphene oxide. On the other hand, the surface adsorbed tea polyphenols can further in situ reduce Ag ions to Ag nanoparticles and stabilize them. The structure and physicochemical properties of the resulting nanohybrid were characterized in detail by UV–vis spectroscopy, Fourier transformation infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. The obtained results indicated that Ag nanoparticles distributed uniformly on the surface of the functionalized graphene. Meanwhile, the so-formed hybrid material could be well dispersed in water forming a homogeneous dispersion due to the stabilization of tea polyphenols. This nanohybrid, combining the unique catalytic properties of Ag nanoparticles with the excellent adsorption and electron transfer ability of graphene, exhibited enhanced catalytic activity toward the reduction of 4-nitrophenol by NaBH 4 . [ABSTRACT FROM AUTHOR]