Magnetic field enhanced surface reconstruction of Fe2P and the promotional effect in electrochemical oxygen evolution

In recent years, the utilization of magnetic fields to enhance the oxygen evolution reaction (OER) performance of catalysts has emerged as an effective approach. However, current research primarily focusing on the impact on magnetic transition metal oxides, and the relevant mechanisms are still worth further exploration. Here, the OER performance of Fe2P loaded on carbon paper (Fe2P/CP) and nickel foam (Fe2P/NF) substrates under in situ magnetic field was investigated. It is revealed that magnetic fields can substantially enhance the OER performance of Fe2P/CP and Fe2P/NF. With a magnetic field of 1.0 T, the current density of 75-Fe2P/CP increases by 28 times (1.8 V vs. RHE), leading to a maximum magnetic current density percentage of 2770%. According to our results, the magnetic enhancement effect is highly correlated with the surface reconstruction of Fe2P to alpha-FeOOH with lower OER energy barriers. Additionally, the spin pinning effect is observed on the alpha-FeOOH/Fe2P interfaces, which leads to the rapid alignment of spin electrons on the surface of catalysts under magnetic field, lowering the O-O coupling energy barrier, and therefore improve OER kinetics. These discoveries have the potential to contribute to a fundamental and comprehensive understanding of electrochemical reactions involving magnetic fields.