title: Shape tailored green synthesis and catalytic properties of gold nanocrystals.
abstract: The use of environmentally benign procedures is highly desirable for the synthesis of nanoparticles. Here we report a simple, versatile, economic, ecofriendly and reproducible green method for the size-tunable synthesis of stable and crystalline gold nanoparticles of varied shape using aqueous extract of Garcinia Combogia fruit. The predominant anisotropic nature in the morphology of synthesized particles at lower quantities of extract gradually shifted to spherical particles with larger quantity of extract and increase of temperature. The onset of reduction, the time-evolution of the Surface Plasmon Resonance (SPR) and the catalytic activity are studied using UV-Visible spectroscopy. The Selected Area Diffraction (SAED) pattern, the lattice fringes in the High Resolution Transmission Electron Microscopic (HRTEM) image and the X-ray Diffraction (XRD) pattern clearly show the pure crystalline nature of the synthesized gold nanoparticles. The role of carboxyl group present in Garcinia Combogia fruit extract in the reduction of chloroaurate ions is established using Fourier Transform Infrared (FTIR) spectra. The size dependent catalytic activity of the green synthesized gold nanoparticles on the reduction of 4-Nitrophenol to 4-Aminophenol using sodium borohydride is studied and reported for the first time. The first order kinetics is fitted and rate constants are calculated. Catalytically active green synthesized gold nanoparticles with controllable size and shape presents an advanced step in future biomedical and chemical applications.
authors.affiliation: Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, India.
authors.forename: Anish
authors.initials: A
authors.lastname: Rajan
authors.forename: M
authors.initials: M
authors.lastname: MeenaKumari
authors.forename: Daizy
authors.initials: D
authors.lastname: Philip
mesh_terms: D000627:Aminophenols / Q000737:chemistry; D002384:Catalysis; D029760:Garcinia / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D055772:Green Chemistry Technology / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D009596:Nitrophenols / Q000737:chemistry; D010084:Oxidation-Reduction; D020349:Surface Plasmon Resonance; D014961:X-Ray Diffraction
chemical_list: D000627:Aminophenols; D009596:Nitrophenols; D006046:Gold; C026729:4-aminophenol; C024836:4-nitrophenol
keywords: 4-Nitrophenol; Catalytic activity; Garcinia Combogia; Gold nanocrystals; Green synthesis; Surface plasmon resonance