Boosting electrocatalytic water splitting by magnetic fields

Overall water splitting efficiency is retarded by the kinetics of the sluggish oxygen evolution reaction (OER). Recently, increasing attention has been attracted to the spin-sensitive nature of the OER and the utility of magnetic fields (MF) for enhancing catalytic performance. Actually, MF should have performed even better, if we had a correct and comprehensive understanding of its possible effects on the whole OER system. Herein, we comprehensively discuss all possible effects of MF on the OER, including the magnetohydrodynamic effect in the electrolyte, the spin selectivity effect in the interface, and the spin alignment and magnetothermal effects in electrocatalysts. We point out that the MF type/setup and the magnetism of electrocatalysts are the two primary determinants for the real effectiveness of MF. This perspective is expected to provide instructive guidance for utilizing magnetic fields to improve the performance of water splitting as well as other spin-sensitive energy conversion reactions.