N-doped FeOOH/RGO hydrogels with a dual-reaction-center for enhanced catalytic removal of organic pollutants.

The stability and activity of the material are promoted by the formation of dual reaction center. • Macroscopic Fe-based graphene catalyst was facile prepared with N doping. • DFT indicated the enhanced formation of dual reaction center by N doping. • MD proved the hydrogen bonding enhanced the electron donor role of pollutant. • The N doping lowered the reduction potential of Fe(II)/Fe(III). A graphene-based hydrogel is prepared by a simple one-step method, establishing a strong dual reaction center and easy separation for efficient pollutant removal from aqueous solution. The FeOOH was grown in situ simultaneously with N doping in a graphene matrix during the self-assembly of graphene hydrogels, resulting in strong interactions in the resulting hydrogel. Density functional theory (DFT) calculation showed that the Fe–π interaction through the Fe–O–C linkage induced the formation of a dual-reaction-center around Fe and C, which was further enhanced by N doping. Furthermore, molecular dynamics (MD) simulations showed that the adsorption process was promoted due to the increase in hydrogen bonding and active sites, further enhancing the electron donor role of pollutant tetracycline for Fe(III) in the Fenton reaction. As revealed by the cyclic voltammetry results, N doping lowered the reduction potential of Fe(II)/Fe(III), which was a key factor in the Fenton reaction. In addition, high stability of the hydrogel was observed after five runs, which suggests promising applications for water treatment. [ABSTRACT FROM AUTHOR]