High-entropy compounds for water electrolysis: insights into dynamic reconstruction behavior and its impact on oxygen evolution reaction catalysis

Component leaching plays a pivotal role in enhancing the activity and stability of high-entropy-based catalysts by triggering structural reconstruction during the oxygen evolution reaction (OER). In this study, we employed soluble V and Mo as sacrificial components alongside a Co stabilizer to synthesize NiFeCoVMo high-entropy catalysts, aiming to simultaneously modulate the reconstruction behavior and optimize catalytic performance. The synergistic interplay between dual-component dissolution and in situ deposition/adsorption mechanisms accelerates structural evolution, ultimately yielding MoO 4 2− -modified NiFeCo oxyhydroxide (NiFeCoOOH-MoO 4 2− ). Mechanistic studies reveal that the NiFeCo-based system is particularly conducive to the reconstruction process, while adsorbed MoO 4 2− function as electronic modulators that redistribute charge densities within the reconstructed layers and reduce surface energy. As a result, this reconstructed catalyst demonstrates exceptional OER activity, achieving an overpotential of 172 mV at 10 mA cm −2 , along with remarkable long-term durability (up to 500 h at 50 mA cm −2 ). This study provides fundamental insights into the origins of the superior electrocatalytic performance of high-entropy materials, paving the way for further exploration and optimization of these advanced catalysts.