Synergistic electronic modulation in CoFeNi/CeO2 enabled by Se-induced surface reconstruction for oxygen evolution reaction

The oxygen evolution reaction (OER) is a pivotal step limiting the efficiency of hydrogen production via water splitting. Developing active and durable non-noble metal electrocatalysts remains challenging. Herein, we propose a strategy combining reconstruction-enabled electronic modulation with an integrated metal-support design. Selenium-modulated CoFeNi/CeO 2 electrocatalysts were synthesized via a cerium-assisted coordination strategy followed by a NaBH 4 -induced reductive surface etching and reconstruction process. The catalyst exhibits a flower-like nanosheet architecture, where oxygen vacancies in CeO 2 interact with selenium-related compositional deviation to regulate the electronic structure of metal centers and optimize the adsorption of reaction intermediates. In alkaline media, the catalyst achieves an overpotential of 247 mV at 10 mA cm −2 , outperforming commercial RuO 2 (322 mV), and a low Tafel slope of 37.91 mV dec −1 . It also demonstrates robust stability over 30 h. Density functional theory (DFT) calculations reveal that reduction-induced selenium redistribution and oxygen-vacancy-associated charge transport cooperatively facilitate proton-coupled electron transfer, accelerating key OER steps. This work establishes a dual-site electronic modulation strategy for efficient OER catalyst design and provides a promising pathway for developing economical and durable electrocatalysts for water-splitting technologies.