Synthesis of nanostructured ZnO, AgZnO and the composites with reduced graphene oxide (rGO-AgZnO) using leaf extract of Stigmaphyllon ovatum

Abstract

A green method is reported for the synthesis of reduced graphene oxide (rGO), zinc oxide nanoparticles (ZnO), AgZnO and rGOAgZnO nanocomposites. The optical properties of the as-synthesized nanomaterials showed bands around 370 nm for ZnO, which red shifted for the nanocomposites with additional band ascribed to the surface plasmon band of Ag around 410–420 nm. The band gap energies were obtained as 3.95, 3.15, 2.45 and 2.75 eV for the rGO, ZnO, AgZnO and rGOAgZnO respectively. The photolumniscent (PL) measurement, at excitation wavelength of 320 nm, showed about four emission peaks for the ZnO nanoparticles with some differences in the spectra of the composites due to reduced surface defects as a result of Stern-Volmer quenching. The photocatalytic studies measured over 120 min reaction time using methlyene blue, showed that the nanomaterials were effective photocatalysts with efficiency of 68.1, 62.7, 61.7 and 57.4% for the rGOAgZnO, ZnO, rGO, and AgZnO respectively.