Hollow-structured ruthenium-nickel-iron metal aerogels boost oxygen evolution reaction

Water splitting for hydrogen production is regarded as one of the essential technologies for sustainable hydrogen generation due to its high efficiency, simplicity, and cleanliness. Nonetheless, a severe constraint is imposed on the overall efficiency and practical implementation of water electrolysis by the slow reaction kinetics of the oxygen evolution reaction (OER). Therefore, designing and developing efficient electrocatalysts is crucial for enhancing OER performances. In this work, Ni₃Fe₂ metallic aerogels (Ni₃Fe₂ MAs) precursors are fabricated via a one-step method and subsequently transformed into hollow-structured Ru₂₄NiFe metallic aerogels (Ru₂₄NiFe MAs) electrocatalysts through an electrochemical displacement approach, which enhances transport of mass species and migration of electrons efficiency. The Ru₂₄NiFe MAs exhibit a reduced overpotential of 241 mV at 10 mA cm^-2 and a Tafel slope of 31.0 mV dec^-1. First-principles calculations further reveal the electrocatalytic mechanism, demonstrating that Ru incorporation significantly reduces the reaction energy barrier and optimizes the adsorption of reaction intermediates on NiFe sites. Moreover, the dual-electrode system composed of Ru₂₄NiFe MAs and PtNi₄ MAs achieves a cell voltage of only 1.51 V for overall water splitting at 10 mA cm^-2, exhibiting electrocatalytic performance and stability far superior to those of Pt/C//RuO₂.