Magnetically-altered eg-orbital occupancy to boost the two-electron oxygen reduction electrocatalysis for faster water decontamination
Baojian Jing, Qi‐Wei Zhang, Minghui Liu, Shilin Yang, Jiayu Zhang, Shan Qiu, Ignasi Sirés, Fengxia Deng
Abstract
Herein, we demonstrate how the magnetic modulation of the e g -orbital occupancy of Co ions can become a novel approach to enhance the two-electron oxygen reduction reaction (2e - ORR) for advanced wastewater treatment by electro-Fenton (EF) process. Nickel foam (NF) substrate coated with ZIF67 was prepared and thermally treated to obtain ferromagnetic NF-supported Co/Co 3 O 4 cathodes, whose response to a small magnetic field was further evaluated in EF. The results show an increase of 62.3 % increase in H 2 O 2 yield and 46.5 % in faradaic efficiency, improving the degradation rate of the antibiotic sulfamerazine from 77.2 % to 92.4 % in 120 min. This enhancement is attributed to improved electron transfer facilitated by the alteration of e g -orbital occupancy of Co ions caused by spin regulation under the magnetic field, rather than to mass transport effects. Therefore, magnetic modulation of the e g -orbital occupancy emerges as a promising strategy to boost EF process for more efficient water decontamination. • Magnetoelectrocatalytic O 2 reduction reaction (ORR) using a ferromagnetic Co-MOF cathode. • The magnetic field-altered e g -orbital occupancy enhanced the ORR in electro-Fenton. • H 2 O 2 concentration rose by 62.3 %, along with Faradaic efficiency up to 46.5 %. • The enhanced electron transfer via spin regulation yielded a faster antibiotic degradation. • Magnetic field-assisted electrochemistry successfully combined with classical catalytic theory.