Structured Selective Activation for Bubble-Controlled High-Rate Alkaline OER

Efficient gas bubble management is critical for advancing alkaline oxygen evolution electrodes, but scalable and cost-effective designs remain limited. Here we present an asymmetrically activated nickel-plate (NP) electrode that couples selective catalyst activation and structured geometry to guide bubble evolution and enhance mass transport. The electrode is fabricated through micromilling, polytetrafluoroethylene (PTFE) coating, and electrodeposition of amorphous nickel-iron (NiFe) catalysts, forming deactivated and activated regions that promote directional bubble release and electrolyte renewal through gridded microchannels. This asymmetric configuration mitigates transport overpotential at high current densities, achieving 408 mV at 1000 mA cm^-2 and a high electrochemically active surface area (ECSA)-normalized current density of 210 mA cm^-2. The monolithic framework, defect-rich amorphous catalysts, and stable PTFE coating ensure sustained performance for over 100 h. This work demonstrates a simple and scalable structural strategy to control interfacial bubble dynamics, providing both high activity and long-term durability for alkaline oxygen evolution reaction.