Silver chloride enwrapped silver grafted on nitrogen-doped reduced graphene oxide as a highly efficient visible-light-driven photocatalyst

Abstract

The visible-light-driven plasmonic photocatalyst silver chloride enwrapped silver/nitrogen-doped reduced graphene oxide (AgCl@Ag/N-rGO) was prepared by a facile hydrothermal-in situ oxidation method and characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). The characterization results reveal that Ag nanoparticles (NPs) were first grafted on N-rGO via N-groups as anchor sites and then enwrapped by AgCl by in situ oxidation. Close interfacial contact favors efficient electron transfer, leading to high photoactivity and photostability for the degradation of various toxic organic pollutants. The photocatalytic performance of this photocatalyst was significantly higher than that of AgCl@Ag/rGO and other related photocatalysts due to the in situ introduction of N-groups. Additionally, the used catalyst can be recycled without an appreciable loss of catalytic activity. Based on electron spin resonance and cyclic voltammetry analyses, the electron transfer processes were confirmed to occur from plasmon-induced Ag NPs to AgCl and from N-rGO to Ag NPs, and pollutants could be oxidized through the loss of electrons to N-rGO by the interaction between the pollutants and N-rGO. The active species of superoxide anion radicals (O2−), photogenerated holes (h+) and surface-adsorbed OH played roles in pollutant photodegradation. Accordingly, the plasmon-induced electron transfer processes elucidated photostability of AgCl@Ag/N-rGO. AgCl@Ag/N-rGO has a potential application in water purification due to its high photoactivity and photostability.