N-doped-carbon encapsulated FeMoxOy nanoparticles for efficiently removing rhodamine B by oxidation of 1O2 generated from H2O2

Abstract

In advanced oxidation processes (AOPs), the degradation of organic pollutants by the oxidation of reactive oxygen species (ROS) generated from the interaction between H₂O₂ and active species Fe²⁺/Fe³⁺ has gained significant attention. The cycle of Fe²⁺/Fe³⁺ in the catalytic oxidation plays a key role. Herein, a kind of N-doped carbon encapsulated FeMo_xO_y nanocrystalline material (FeMo@NC) was fabricated using a precipitation–calcination approach and applied to degrade organic pollutants in AOPs. The composite catalyst presents efficient catalytic activity for removing rhodamine B (RhB), methylene blue (MB), congo red (CR) and methyl orange (MO). The facilitating effect of Mo on the Fe²⁺/Fe³⁺ cycle and the phase structure and composition of the catalyst on the degradation was explored. Meanwhile, the recovery and reusability of the catalyst were assessed, proving its excellent stability in the degradation process. Quenching experiments demonstrate that the catalyst can activate H₂O₂ to generate singlet oxygen (¹O₂) that serves as the main ROS to degrade RhB, and the degradation pathway and mechanism are then proposed.