A 2D porous Fe2O3/graphitic-C3N4/graphene ternary nanocomposite with multifunctions of catalytic hydrogenation, chromium(vi) adsorption and detoxification

Abstract

A facile and green approach for the preparation of a multifunctional ternary Fe₂O₃/graphitic-C₃N₄/graphene (FeCNG) nanocomposite with a porous structure is reported. This entails the growth of Prussian blue (PB) and adsorption of urea on graphene oxide (GO), followed by thermal pyrolysis of PB and urea leading to in situ formation of a porous N-doped graphene/iron oxide architecture. This strategy for the generation of FeCNG requires no structure-directing surfactants and gives rise to an N-doped composite capable of separation for recycling. The FeCNG architecture is capable of both rapid reduction of p-nitrophenol (4-NP) and efficient scavenging of Cr(VI) in aqueous media. The reduction of 4-NP to p-aminophenol by NaBH₄ could be achieved within 3 min at 25 °C, using catalyst loadings as low as 1 mg. Cr(VI) adsorption was evaluated by Langmuir and pseudo-second-order models, offering a maximum equilibrium adsorption capacity of 149 mg g⁻¹. In particular, Cr(VI) could be effectively adsorbed by the FeCNG nanocomposite and thereby reduced to less toxic Cr(III). By virtue of the enhanced catalytic performance and highly efficient adsorption of Cr(VI) across a wide pH range, the FeCNG nanocomposite possesses a broad application potential in energy and environmental sciences.