Facilitating Reconstruction of the Heterointerface Electronic Structure by the Enriched Oxygen Vacancy for the Oxygen...

Exploring high-performance non-precious metal-based electrocatalysts for the sluggish oxygen evolution reaction (OER) process is fundamentally significant for the development of multifarious renewable energy conversion and storage systems. Oxygen vacancy (V_o) engineering is an effective leverage to boost the intrinsic activity of OER, but the underlying catalytic mechanism remains anfractuous. Herein, we realize the construction of oxygen vacancy-enriched porous NiO/ln₂O₃ nanofibers (designated as Vo-NiO/ln₂O₃@NFs hereafter) via a facile fabrication strategy for efficient oxygen evolution electrocatalysis. Theoretical calculations and experimental results uncover that, compared with the no-plasma engraving component, the presence of abundant oxygen vacancies in the Vo-NiO/ln₂O₃@NFs is conducive to modulating the electronic configuration of the catalyst, altering the adsorption of intermediates to reduce the OER overpotential and promote O* formation, upshifting the d band center of metal centers near the Fermi level (E_f), and also increasing the electrical conductivity and enhancing the OER reaction kinetics simultaneously. In situ Raman spectra proclaim that the oxygen vacancy can render the NiO/ln₂O₃ more easily reconstructible on the surface during the OER course. Therefore, the as-obtained Vo-NiO/ln₂O₃@NFs demonstrated distinguished OER activity, with an overpotential of only 230 mV at 10 mA cm^-2 and excellent stability in alkaline medium, surmounting the majority of the previously reported representative non-noble metal-based candidates. The fundamental insights gained from this work can pave a new path for the electronic structure modulation of efficient, inexpensive OER catalysts via Vo engineering.