Expensive platinum group metals (PGMs) are used to enhance the anodic oxygen evolution reaction (OER) kinetics, and they represent a real bottleneck in the commercialization of anion exchange membrane water electrolyzers (AEMWEs). Therefore, we present a scalable and economical homogeneous precipitation method to synthesize Ni x Fe 1‐ x O nanoparticles with different Ni/Fe ratios, while reducing the dependence on expensive PGM‐based electrocatalysts. The effects of Ni/Fe ratios in the synthesized Ni x Fe 1‐ x O, along with morphological and surface chemical characteristics, on electrocatalytic performance were thoroughly investigated with half‐cell measurements. Furthermore, critical electrode design factors, that is, ink composition and electrocatalyst loading, were scientifically investigated and optimized. Among the explored compositions, amorphous Ni 0.28 Fe 0.72 O and crystalline Ni 0.66 Fe 0.34 O exhibited superior OER activity, achieving mean overpotentials of 359 mV and 359.1 mV at 10 mA cm −2 , respectively. This superior activity was attributed to a higher concentration of Ni 3+ (NiOOH), a highly active compound for OER. These high‐performing samples were integrated as anodes in a lab‐scale AEMWE for device‐level evaluation. Ni 0.28 Fe 0.72 O achieved the highest performance at 80 °C, by delivering the current density of 7.81 A cm −2 against a cell voltage of 2.2 V. Whereas, Ni 0.66 Fe 0.34 O achieved a current density of 6.49 A cm −2 at 2.2 V. Both samples exhibited excellent stability during short‐term durability tests (ca. 90 h) at 1 A cm −2 and 80°C.
Muhammad et al. (Fri,) studied this question.