Oxygen Evolution Reaction Performance Of Co-based Single-atom Catalyst Under Alternating Magnetic Field

At present,single-atom catalysts（SACs）are considered to be the most promising catalysts for oxygen evolution reaction（OER）due to their maximum atom utilization and unique catalytic activity.So far,many efforts to improve their OER performance are focused on increasing single atoms（SAs）loading amount and the synergistic interactions.However,these approaches inevitably suffer from some problems,such as cluster formation and unclear synergistic mechanisms.Therefore,especially for kinetically slow four-electron coupled OER with sluggish kinetics,new alternative strategies aiming at enhancing the single-atom catalyst activity,which is a worth exploring challenge.Alternating magnetic field（AMF）,which have long been used in the medical field,have recently emerged as a new way to modulate electrocatalytic performance.Magnetic nanoparticles under AMF have been reported to induce magnetic heating associated with Néel relaxation due to internal flip of the spin relative to the crystalline lattice.The locally heated magnetic electrocatalysts are desired to optimize OER performance while avoid the expense of the overall reactor lifetime and energy consumption.The application of AMF to magnetic single-atom catalysts,using the local magnetic heating generated by the spin flip of magnetic catalysts,will provide great opportunities for further enhancement of OER performance.In this work,we first fabricated Mo S₂ monolayer by pulsed laser deposition technique,theoretical calculations showed that the cobalt（Co）SAs tends to be energetically anchored to the Mo top sites,and then the laser molecular beam epitaxy method was employed to directly anchor magnetic Co SAs at the Mo top sites of monolayer Mo S₂（Co@Mo S₂）.Theoretical calculation shows that the anchoring of magnetic Co SAs induces ferromagnetic properties and improves the OER performance,and the experimental results are consistent with the theoretical calculations that Co@Mo S₂ has lower overpotential and exists in-plane room temperature ferromagnetic properties.The spin polarization direction of magnetic Co@Mo S₂ is consistent with the direction of the applied static magnetic field,and it varies with the direction of the applied static magnetic field.On this basis,the magnetic Co@Mo S₂ achieves spin flipping by constantly changing spin polarization under AMF,which generates local magnetic heating and further improves its OER performance.This work is also applicable to other magnetic SACs,which provides a new idea to enhance the OER activity of magnetic SACs.