ZnO nanosheet-assisted immobilization of Ag nanoparticles on graphene/Ni foam for highly efficient reduction of 4-nitrophenol

Abstract

The excellent catalytic properties of silver (Ag) nanoparticles (AgNPs) are generally deteriorated during use because of their irreversible agglomeration and the surfactants coating them. In this research, a novel hybrid structure of as-synthesized silver nanoparticles/zinc oxide nanosheets/graphene/nickel foam (AgNPs/ZnO/Gr/NiF) was prepared using chemical vapor deposition (CVD) combined with a hydrothermal reaction and in situ reduction with ascorbic acid. The as-prepared AgNPs/ZnO/Gr/NiF hybrid structure was characterized using Raman spectrometry, scanning electron microscopy, and X-ray diffraction. The ZnO nanosheets were identified as an effective buffer layer to improve the homogeneity and stability of the as-synthesized AgNPs on the surface of Gr/NiF hybrid structure because of its assisted role in carrying and immobilizing the AgNPs to the surface of Gr/NiF via chelation and complexation of arginine to both ZnO and Ag ions during the in situ reduction process of Ag ions. The as-prepared AgNPs/ZnO/Gr/NiF hybrid structure is flexible and exhibits high efficiency and recyclability for the reduction of 4-nitrophenol to 4-aminophenol.