Magnetic Field Enhances Interfacial Electron Redistribution to Promote Magnetoelectrocatalytic Hydrogen Evolution

Abstract

The rational design of efficient and cost-effective electrocatalysts for the hydrogen evolution reaction (HER) presents significant challenges. Enhancing the overall performance of electrocatalytic reactions mainly focuses on optimizing catalytic materials and structures. Furthermore, the implementation of external magnetic fields may also effectively stimulate electron transportation. In this context, a novel method was introduced to enhance the HER efficiency of layered ferro-catalysts (Mo2C/Fe3C) by integrating intrinsic driving forces and non-contact field stimulation through both interface engineering and external magnetic fields. Experiments combined with theoretical calculations indicated that the built-in electric field (BEF) induced by the work function (WF) is beneficial to the redistribution of interfacial charge, thereby optimizing the Gibbs free energy of H*, which enhances HER activity. Moreover, the integration of an external magnetic field into the electrochemical system has been shown to enhance the catalytic performance further. A significant reduction in overpotential of approximately 25% was observed at a current density of 10 mA·cm-2 when subjected to a micromagnetic field of 50 mT, resulting in a decrease to 91 mV. The results show that the conductivity and interfacial charge transfer of ferromagnetic catalysts assisted by magnetic field are enhanced due to the negative magnetoresistive (MR) effect. Additionally, the Lorentz force facilitates the escape of hydrogen bubbles from the electrode surface, thereby contributing to the enhancement of reaction efficiency. This work presents a promising strategy for enhancing the catalytic activity of HER through the integration of electrical and magnetic stimuli.