Anion exchange membrane water electrolysis (AEMWE) is an attractive technology for the production of green hydrogen and has advantages in terms of cost owing to the use of non-precious catalyst materials. NiFe-based materials are the best-in-class electrocatalysts for the alkaline oxygen evolution reaction. Defining the active sites of NiFe-based materials has been a controversial issue over the past decades. Previously, Ni was regarded as an active site; however, active sites, such as Fe or Ni–Fe dual active sites have been considered in recent studies. Despite the complexity of heterogeneous catalysis, with the aid of in situ/operando measurements and density functional theory (DFT) calculations, Fe was selected as the ultimate active site in state-of-the-art materials. However, the electrocatalyst suffers from rapid degradation in Fe-purified KOH. Herein, we report a catalyst/electrolyte interface engineering strategy using tetraphenylporphyrin (TPP) to alleviate the destabilization of NiFe-based catalysts. The online electrochemical flow cell inductively coupled plasma-optical emission spectroscopy proved that thermodynamically unstable Fe liberation was the primary cause of deactivation. TPP acts as a protective layer and suppresses hydrated metal dissolution at the catalyst/electrolyte interface. The stable TPP layer on NiFe elongates the lifetime near the electrode, enhancing the redeposition kinetics of the active site, Fe. As a proof of concept, the role of TPP was validated at the half-cell and 2.4 times suppression of degradation rate in AEMWE scale at a constant current density of 500 mA cm^-2. This strategy of using a TPP as a protective layer may serve as a new platform for stable oxygen evolution electrocatalysts.