Oxygen radical coupling on short-range ordered V sites for enhanced oxygen evolution reaction activity

Abstract

The development of efficient oxygen evolution reaction electrocatalysts is crucial for the sustainable conversion of clean energy sources. However, most catalytic materials that mainly adhere to the traditional adsorbate evolution mechanism or the lattice oxygen-mediated mechanism, often struggle to strike a balance between high activity and stability. Herein, we designed VN/C electrocatalyst that followed an unconventional oxide path mechanism. This catalyst triggered direct *O-O* radical coupling, resulting in a V-O-O-V intermediate and effectively bypassing the formation of *OOH species. It demonstrated excellent catalytic performance with low overpotentials of 221 and 280 mV at 10 and 50 mA cm⁻², a small Tafel slope of 62.8 mV dec^–1, a high Faraday efficiency of 98.6 % and remarkable stability under continuous 50 h operation (at 1.47 V vs. RHE). Furthermore, density functional theory (DFT) calculations and in situ infrared spectroscopy and Raman spectroscopy revealed that *O intermediates can be directly coupled to form *O-O* radical coupling at V sites, thus overcoming the limitations associated with the four-electron transfer steps in OER. This work offers valuable insights and foundation for the development of symmetric dual-site OER catalysts with oxide path mechanism.