The regulation of multiple 3d orbits triggers the self-equilibrium effect of high-entropy oxide in seawater electrolysis

Seawater electrolysis is undoubtedly a more sustainable alternative to pure water electrolysis at present. However, it is hindered by the relatively slow kinetics of the oxygen evolution reaction and the detrimental effects of chloride ions in seawater that require resolution. In this study, we developed a straightforward synthesis method and successfully prepared FeNiCoMnCr high-entropy oxide (HEO). The strong coupling among multiple 3d orbitals of the transition metals allows for significant regulation of the catalyst’s electronic structure, enabling oxidation and reduction processes at the active site to spontaneously approach an equilibrium state. Additionally, Lewis acid Cr⁶⁺ selectively adsorbs OH⁻, further enhancing both activity and stability of the catalyst in alkaline seawater. This research provides valuable insights into utilizing HEOs for seawater electrolysis and elucidates the roles of metals within HEOs.