Constructing heterointerfaces to enhance electron transfer of CoFe/CoFe2O4 mediated electro-Fenton process for bisphenol A degradation: Mechanistic insights and performance evaluation

The inefficient electron transfer and Fe(III)/Fe(II) cycle remain significant obstacles in the electro-fenton process. Herein, a nitrogen-doped graphite felt (NGF)-supported CoFe/CoFe2O4 heterostructure is synthesized that achieves highly efficient interfacial electron transfer and stable Co/Fe redox cycle. Theoretical calculations demonstrate that the CoFe/CoFe2O4 heterointerfaces induce local charge redistribution benefiting from the electronic communication between electron acceptor (CoFe2O4) and electron donor (CoFe). Analysis of the Fermi level indicates that the introduction of CoFe alloy enhances the electron density of the catalyst. The CoFe/ CoFe2O4@NGF cathode can remove bisphenol A (BPA) completely in 90 min, and the pseudo-first-order kinetic constant (0.0625 min(-1)) is 23 times higher than the GF system. Notably, the CoFe/CoFe2O4@NGF electrode maintains excellent catalytic capability and stability within a broad pH range (3-11). The construction of the CoFe/CoFe2O4 heterostructure reduces the adsorption energy of oxygen, which ultimately increases the yield of reactive oxygen species (ROS). Quenching experiments revealed that hydroxyl radical (center dot OH) played a dominant role in the degradation of BPA, and significantly reduced the biotoxicity of intermediate products. This work offers a dependable approach for developing bimetallic catalysts with high catalytic activity.