Enhancement of methylene blue catalytic reduction by novel green synthesized metal decorated reduced graphene oxide: Sn@rGO and Ag@rGO

Abstract

Carbon-based nanocomposites (NCs) attracted much attention in heterogeneous catalysis to remove organic dyes. Herein, a novel low-cost green approach was utilized to design a reduced graphene oxide (rGO) impregnated with Sn or Ag nanoparticles (NPs) using ginger extract as a green reducing agent. The synthesized NCs were characterized utilizing X-ray diffraction (XRD), Fourier transformation infrared (FTIR), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), Raman spectroscopy, and thermal gravimetric analysis (TGA). The synthesized NCs were assessed for their catalytic reduction activity towards methylene blue (MB) dye. XRD displayed the characteristic peaks of Sn- and Ag-NPs and the reduction of GO, referring to successful NC formation. FTIR and Raman confirmed the reduction of GO and the incorporation of Sn and Ag-NPs into the GO surfaces. TEM results proved that either Sn- or Ag-NPs was uniformly dispersed on rGO sheets with average sizes of 4.129 and 7.293 nm, respectively. EDX spectra of Sn@rGO- and Ag@rGO-NCs revealed the presence of C, O, Sn, and Ag. TGA confirmed the increased thermal stability of the NCs as compared to GO. Ag@rGO-NC exhibited stronger catalytic MB reduction (97% after 10 min) than Sn@rGO-NC (80% after 20 min). To the best of our knowledge, this is the first time Sn@rGO-NC has been designed for MB catalytic reduction, which gives rise to its promising capacity for future catalytic applications.