Breaking the activity-stability trade-off via dual-mechanism induced by rare earths for lasting seawater electrolysis

Triggering the adsorbate evolution and lattice oxygen mechanisms coupled path holds promise for overcoming the activity-stability trade-off of oxygen evolution reaction (OER). However, achieving precise regulation and activation of multiple OER pathways via 3d-metal modification strategy remains challenging due to the external effects of crystal fields and coordination environments. Herein, we propose an atomic-dispersed rare earth substitution strategy to construct a spatially partitioned reaction mechanism, and achieve dual activation between adsorbate evolution and lattice oxygen mechanisms. The strong shielding effect of 5 s/5p electrons in RE significantly reduces the influence of the external environment on the 4 f orbitals, thereby enhancing the controllability of the reaction pathway. The optimized Sm-NiMoO4 exhibits favorable OER performance. At an industrial temperature of 70 °C, the OER in simulated seawater exhibits an overpotential of only 214 mV at 0.5 A cm−2, while maintaining stability for 1500 h. Preliminary techno-economic analysis reveals that the cost of hydrogen produced from the Sm-NiMoO4 is US$2.56 kg−1. This synthetic strategy and mechanism analysis represent a valuable contribution towards achieving industrial-scale seawater hydrogen production. Seawater electrolysis is promising for sustainable hydrogen production but is limited by the activity-stability trade-off of oxygen evolution catalysts. Here, the authors report a rare-earth substitution strategy that couples oxygen evolution pathways, enabling efficient and durable seawater electrolysis.