Catalysis Under Alternating Magnetic Field: Rethinking the Origin of Enhanced Hydrogen Evolution Activities

Abstract Magnetic fields are proposed to be a clean and powerful tool to boost the heterogeneous reaction processes, from the simple two‐electron transfer hydrogen evolution to the complicated proton‐coupling of multi‐electron transfer reactions. Although many mechanisms are proposed to explain the field‐assistant enhancement of activities, it remains an open question of how to understand the contradictory experiment results. In this study, the interplay between the alternating magnetic field (AMF) and the working electrodes from the viewpoint of their relative geometric positions is investigated. It is found that the HER current is almost doubled at an AMF of 25 mT when Pt foil and AMF are parallelly arranged, which is more significant than the perpendicularly arranged configuration. A significant increase in solution resistance is observed, which is in contradiction to previous works. The changing of currents with the AMF strength is investigated for the diamagnetic Cu, ferromagnetic Ni, and paramagnetic Ti and Pt wire, all suggesting the vital role of the induced electromotive force, which is a result of the relative geometric positions between the electrode and AMF. The findings provide an alternative mechanism for the magnetic field‐assisted electrocatalytic processes, which is helpful for the rational design of high‐performance catalysts.