Evaluation of solanum nigrum leaf extract as a corrosion inhibitor and reductant for the green synthesis of gold nanoparticles.

ABSTRACT

Eco-friendly green methodologies have attracted the attention in every field of research owing to environmental pollution and the alarming development of global warming. In search for eco-friendly materials for the synthesis of metal nanoparticles and corrosion inhibition, the leaf-extract of Solanum nigrum have identified, as it displays remarkable antioxidant property. The leaf-extract was investigated by weight-loss method and potentio-dynamic polarization technique in carbon steel to study the corrosion inhibition. Surface and protective film analysis was carried out using scanning electron microscopy (SEM). The antioxidant property of the leaf-extract was exploited for synthesis of gold nanoparticles (GNPs). Excellent results were obtained when the leaf-extract was used to reduce AuCl4. The formation of GNPs was rapid and within a few hours AuCl4 was reduced into fine GNPs as evidenced by the appearance of deep ruby red colloidal dispersion. The UV–visible spectral analysis revealed the reduction of AuCl4 and showed a peak at ~545 nm originating from the surface plasmon resonance of GNPs. The GNPs were characterized using SEM with energy-dispersive X-ray spectroscopy, powder X-ray diffraction and zeta potential analysis. The average size, geometrical shape and the zeta potential were discussed.