Catalytic reduction of methylene blue using biogenic gold nanoparticles from Sesbania grandiflora L

•Single step and rapid synthesis of AuNPs using Sesbania gandiflora was described.•TEM analysis showed the distribution of spherical and triangle shaped AuNPs.•Au nanoparticles have catalytic activity on reduction of methylene blue.•The reduction of methylene blue followed pseudo-first-order kinetic model.

In the present investigation, we report the synthesis of gold nanoparticles (AuNPs) using leaf extract of Sesbania grandiflora. The processes of nucleation and growth of AuNPs were followed by monitoring the absorption spectra during the reaction. UV–vis spectrum of the aqueous medium containing AuNPs showed a peak at around 534 nm. FE-SEM and TEM micrograph analysis of the AuNPs indicated that they were predominantly spherical, well-dispersed within 7–34 nm. The synthesized AuNPs are observed to have an excellent catalytic activity on the reduction of methylene blue by S. grandiflora extract which is confirmed by the decrease in absorbance maximum values of methylene blue (MB) with respect to time using UV–vis spectrophotometer and is attributed as an effective catalyst for degrading chemical dyes.