Harnessing persistent magnetism on intermetallic PtCo hard magnets for enhanced hydrogen evolution

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Magnetoelectrochemistry has emerged as a promising approach for enhancing hydrogen production performance via water electrolysis. However, despite enabling multifunctional control, the inherent structural complexity of external magnetic field configurations significantly complicates device integration and scalability in electrochemical systems. Herein, we introduced hard magnetic catalysts that provide persistent magnetism to manipulate the reaction. In this case, the electrocatalysis device requires no external magnetic field configuration, as the magnetized catalyst internally supplies a persistent one. As a model, we employed hard-magnetic L10-ordered PtCo (L10-PtCo) nanoparticles to harness the persistent magnetism of the catalyst itself for boosting hydrogen evolution reaction (HER) performance. As a result, the magnetized L10-PtCo (L10-PtCo-AM) with built-in magnetic field demonstrated superior performance compared to its non-magnetized counterpart (L10-PtCo-NM) and even outperforms the catalyst under the application of an external magnetic field (L10-PtCo-UM). Detailed analysis reveals that the enhanced HER kinetics arise from the modulation of the solid–electrolyte interface by persistent magnetism. Upon removal of the external magnetic field, the magnetic domains at the surface of the magnetized L10-PtCo catalyst exhibit a high degree of conformity with its anisotropic catalyst surface. Consequently, this highly matched micro-local surface and magnetic structure can significantly enhance the magnetic catalytic gain. This approach of leveraging the intrinsic magnetism of catalysts holds significant potential for enhancing the efficiency of catalytic applications.