3D porous and redox-active prussian blue-in-graphene aerogels for highly efficient electrochemical detection of H2O2

Abstract

3D porous and redox-active prussian blue-in-graphene (PB@G) aerogels with mass ratios of graphene to PB from 2.5 : 1 to 1 : 2.5 have been fabricated for the first time by supercritical fluid drying of its hydrogel precursors, which have been synthesized by co-reduction of graphene oxide and FeCl₃ with L-ascorbic acid as the reducing agent in the presence of ferricyanide. The chemical composition and crystalline structure of the resulting PB@G aerogels, as well as the strong interaction between graphene sheets and PB nanoparticles, have been disclosed by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and X-ray powder diffraction (XRD). The morphology and hierarchically porous attributes of the resulting PB@G aerogels have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption–desorption tests. The electrical conductivity and electrochemical performance of the resulting PB@G aerogels have also been revealed in this study. The as-synthesized PB@G aerogel monoliths possess large surface area (601 m² g⁻¹), abundant pore volume (3.8 cm³ g⁻¹) and high conductivity (38.4 S m⁻¹), and the electrodes modified with the as-synthesized PB@G aerogels have performed very well in the electrocatalytic reduction of H₂O₂ with a very low limit of detection (5 × 10⁻⁹ M) and a wide linear range (0.005–4 mM). These results imply that in situ encapsulation of different nanoscale materials into 3D graphene aerogel framework may open up a significant avenue to fabricate a series of graphene-based 3D porous materials with promising applications.