Facile synthesis of biogenic gold nanocatalyst for efficient degradation of organic pollutants

Abstract

Mimosa pudica (M. pudica) leaves extract mediated environmental benign synthesis of gold (Au) nanoparticles (NPs) in aqueous medium at room temperature. The growth of these nanoscopic Au particles was monitored by UV–vis spectrophotometer. The particles have spherical shape with narrow size distribution. The average diameter of the Au NPs is 16nm as determined from HRTEM. The ensuing nanodimensional Au particles were used as an efficient nanocatalyst in the degradation of organic pollutants like dye such as rhodamine B (Rh B) and aromatic nitrocompound such as o-nitrophenol (ONP) in the presence of NaBH4 in aqueous medium at room temperature. Both the reactions were assayed spectrophotometrically and are of first order. In the absence of catalyst, the reactions occur extremely slow but enhance abruptly upon addition of Au NPs indicating their catalytic efficacy. Such significant catalytic behavior of the so-synthesis Au NPs can be attributed to their large number of active sites for the reactant molecules to interact by serving an electron relay effect.