A facile, one-pot and eco-friendly synthesis of gold/silver nanobimetallics smartened rGO for enhanced catalytic reduction of hexavalent chromium

Abstract

A one-pot synthesis of rGO, AgNPs, rGO/AgNPs, AuNPs, rGO/AuNPs, Ag-AuNPs and rGO/Ag-AuNPs using Albizia saman leaf extract as a reducing and stabilizing agent is reported herein. The obtained nanomaterials were characterized by UV-Vis, FT-IR, XRD, TEM and EDX analyses, and were involved as innovative catalysts in the conversion of toxic Cr⁶⁺ to benign Cr³⁺, using formic acid as a reducing agent. The green synthesized rGO/Ag-AuNPs show superior catalytic activity, stability and reusability, due to the synergistic effect of rGO and Ag-AuNPs, compared to rGO, AgNPs, rGO/AgNPs, AuNPs, rGO/AuNPs and Ag-AuNPs. The kinetics, efficiency and mechanism of catalytic depollution process have been investigated and discussed. Hybrid materials of this kind are easy to prepare and can be used in the environmental remediation process.