The Degradation Mechanism of Nonprecious Ni ₄ Mo-MoO ₂ Cathode during Intermittent Alkaline Water Electrolysis

) during intermittent AWE. First, the dissolved oxygen that inevitably diffuses from the anode to the cathode chemically corrodes the NiMo catalyst in concentrated alkaline electrolyte at high temperature, thus reducing active sites and leaching critical components, notably Mo. Simultaneously, the reverse current generated during start-stop operations induces anodic polarization of the NiMo cathode, accelerating its degradation through electrochemical oxidation. Moreover, driven by external gas-liquid flow scouring and internal stress from redox-induced phase transformation, the catalyst layer separates from the substrate, leading to serious mechanical detachment. These factors collectively cause severe degradation in the activity of the NiMo cathode. This work provides important guidelines for developing next-generation nonprecious metal cathodes with lasting stability.