Accelerated Proton Transfer Channel for Breaking the Bottlenecks of Activity and Stability at Industrial-Scale Anion...

Nickel-iron-based oxides are promising alkaline oxygen evolution reaction (OER) electrocatalysts, yet their practical implementation in anion exchange membrane (AEM) water electrolysis remains challenging for large-area membrane-electrode assembly (MEA) and stability due to complex synthesis and metal leaching issues. Herein, a scalable NiFeV_0.5O electrocatalyst achieves the single-batch production of tens of grams and facilitates the fabrication of a 100 cm² MEA using the catalyst-coated membrane (CCM) approach. Using various in situ characterization methods, we track the OER intermediates and identify the dynamic leaching and readsorption of VO_x ^- species. We pioneer an operando rotating ring-disk electrode (RRDE) methodology with IrO_x pH-sensing probes, which maps the interfacial acidity and demonstrates that these species elevate the local pH by 1.8 units via a hydrogen-bond-accelerated proton transfer channel. Experimental and computational analyses reveal that the readsorbed VO_x ^- species are anchored via directional Fe─O─V bonds, suppressing Fe leaching by eight-fold compared to conventional NiFeO. Notably, when the gram-scale synthesized NiFeV_0.5O is applied as an anode catalyst in a practical AEM water electrolyzer, it delivers 3.0 A cm^-2 at a cell voltage of 1.88 V and exhibits remarkable stability at 1 A cm^-2 over 500 h with a low decay rate of 0.12 mV h^-1.