Pr6O11-driven electron modulation via d-f orbital hybridization for alkaline seawater electrolysis

Abstract

Rare-earth modulation provides an effective route to tune electronic structure of transition metals for oxygen release. However, the role of d-f orbital hybridization in governing interfacial charge behavior on the electrochemical oxygen evolution reactions (OER) remains unclear. Herein, an in situ electrochemical reconstruction strategy is developed to transform Pr-doped CoP/Fe2P nanoparticles into a threedimensional CoFeOOH nanosheet network decorated with Pr6O11 clusters under operating conditions, where Pr6O11 acts as an electron modulator to regulate interfacial charge behavior. Strong d-f orbital hybridization between Pr 4f and Co/Fe 3d orbitals delocalizes electrons and accelerates interfacial charge transfer, enhancing oxygen evolution kinetics. Consequently, charge redistribution between Pr6O11 and CoFeOOH modulates the electronic structure to optimize intermediate adsorption for lowering energy barrier. Meanwhile, dynamically evolved Pr6O11 clusters suppress Cl− adsorption while enhancing OH− binding affinity, thereby ensuring outstanding activity under simulated seawater conditions. The Pr6O11-CoFeOOH electrode exhibits improved OER performance, requiring overpotentials of 223 and 233 mV at 100 mA cm-2 in alkaline freshwater and simulated seawater, respectively. When applied in a Pt/C || Pr6O11-CoFeOOH anion-exchange membrane electrolyzer, the system consistently delivers 500 mA cm-2 at 1.7 V and operates stably over 500 hours. This work reveals a feasible strategy for constructing robust electrocatalysts through d-f orbital hybridization, enabling efficient electrochemical energy conversion.