R.Z. Jiang, J.F. Zhang, Y.P. Xie *, L.Y. Wu, J.J. Gao *, Y. Wang, Z.C. Xu, F.B. Su *, Z.-S. Wu *, S.S. Yuan and G.W. Xu *

Small, 2024, Accepted.

Understanding the reconstruction mechanism to rationally design cost-effective electrocatalysts for oxygen evolution reaction (OER) is still challenging. Herein, a defect-rich NiMoO4 precatalyst was developedused to explore its OER activity and reconstruction mechanism. In-situ generated oxygen vacancies, distorted lattices, and edge dislocations expedite the deep reconstruction of NiMoO4 to form polycrystalline Ni (oxy)hydroxides for alkaline oxygen evolution. It only needs ~ 230 and ~ 285 mV to reach 10 mA/cm2 and 100 mA/cm2, respectively. The reconstruction boosted by the redox of Ni was experimentally confirmed experimentally by sectionalized CV activations at different specified potential ranges combined with ex-situ characterization techniques. Subsequently, the reconstruction route was elucidated presented based on the acid-base electronic theory. Accordingly, the dominant contribution of the adsorbate evolution mechanism to reconstruction during oxygen evolution was revealed. This work developed a novel route to synthesize defect-rich materials and provided new tactics to investigate the reconstruction.