 This study proposes a one-step method to modulate oxygen defects in Ni-fail-air double hydroxide, Ni-fail-DH, Slash-Fail-OH heterostructure, which enhances the electrocatalytic activity of OER by promoting synergy between the adsorbate evolution mechanism and SLOM. The optimal Ni-Fail-DH Slash-Fail-OH heterostructure outperforms non-noble OER catalysts with an overpotential of 177 mV to deliver a current density of 20 mA Cm-2 and high stability. Demonstrating a facile and versatile approach to designing highly active TML-DH-based OER electrocatalysts for energy and environmental applications. This article was authored by Wuhan Wang, Laili, Jingwei Shui, and others.