Abstract
The catalytic activity and stability of an iron-nickel based oxygen-deficient perovskite for the oxygen evolution reaction (OER) are drastically improved with the ppm additive of Fe ions to the alkaline electrolyte. The enhancement is attributed to a 1-2 nm restructured Ni0.5Fe0.5Ox(OH)2-x (oxy)hydroxide layer, as demonstrated with scanning transmission electron microscopy. La0.6Ca0.4Fe0.7Ni0.3O2.9 shows almost a four-fold increase in OER activity after Fe addition relative to the as-prepared pristine electrolyte, which demonstrates the low Tafel slope of 44 ± 2.4 mV dec-1 and the superior intrinsic activity of 706 ± 71 A g-1oxide at 1.61 V vs. RHE.