Self-assembly of amine-functionalized gold nanoparticles on phosphonate-functionalized graphene nanosheets: a highly active catalyst for the reduction of 4-nitrophenol

Abstract

Graphene nanosheet (GNS) supported gold nanoparticle (Au-NP) composites (Au-NP/GNS) have attracted a lot of attention due to their important applications in catalysis, sensing, optics, medicine, and fuel cells. In this study, based on the strong electrostatic and/or hydrogen bonding interactions between the amine-functionalized Au-NP (Au-NP@NH₂) and phosphonate-functionalized GNS (GNS-PO₃H₂), a self-assembly strategy was used to synthesize Au-NP/GNS composites. The physical and chemical properties of Au-NP@NH₂, GNS-PO₃H₂, and the Au-NP/GNS composites were fully investigated using various physical characterization, including X-ray powder diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, transmission electron microscopy, and zeta potential analysis. The experimental results demonstrate that the phosphonate-functionalization of GNS was critical for the generation of high-quality Au-NP/GNS composites. The as-prepared Au-NP/GNS composites show improved catalytic activity for the degradation of 4-nitrophenol compared to functionalized Au-NP, which was ascribed to the amine-functionalization of the Au-NP and the introduction of the GNS with high electrical conductivity and large surface area.