Flash‐Combustion Synthesis of Self‐Anchored Spinel Oxides via In Situ Ni Diffusion for Robust Water Oxidation

Constructing robust, binder‐free electrodes with intimate substrate‐catalyst contact is pivotal for advancing alkaline water electrolysis but remains impeded by complex synthesis procedures and weak interfacial adhesion. Herein, we present a rapid flash combustion synthesis strategy to fabricate a self‐anchored Ni‐Co‐Fe spinel oxide electrode (Ni 1 Co 1 Fe 1 O‐NF) via in situ substrate diffusion. By exploiting the transient high‐temperature thermal shock generated by igniting Co/Fe precursors on Ni foam, Ni atoms from the substrate are driven to diffuse outwards and react with the precursor layer. This process simultaneously establishes a compositionally graded, metallurgically bonded interface and a hierarchical porous network formed by gas expansion. The resulting Ni 1 Co 1 Fe 1 O‐NF electrode exhibits exceptional oxygen evolution reaction (OER) performance, requiring an overpotential of 254 mV to deliver a current density of 100 mA cm −2 and maintaining industrial‐level stability for over 1 week. Density functional theory (DFT) calculations reveal that the in situ incorporated Ni optimizes the electronic structure and triggers a switch from the conventional adsorbate evolution mechanism (AEM) to the energetically favorable lattice‐oxygen‐mediated (LOM) pathway. This work provides a scalable, energy‐efficient paradigm for designing monolithic, high‐performance electrodes for sustainable hydrogen production.