Synergistic effects of water content and synthesis temperature on tailoring oxalate-derived nickel-iron (Oxy)hydroxide for improving oxygen evolution reaction

The oxygen evolution reaction (OER) is a primary bottleneck that disturbs the efficient hydrogen production from water using renewable electricity. Despite extensive studies, current benchmark NiFe oxyhydroxide catalysts need further development to reduce significant overpotentials for efficient OER. Here, we show that an oxalate-derived OER catalyst immediately converted to NiFe hydroxides in KOH is a promising candidate as a suitable OER catalyst. We find the significant influence of varying water content on morphological changes and Fe dispersion, impacting the intrinsic OER kinetics of the catalysts. Furthermore, the synthesis temperature proves crucial in controlling oxalate growth rates and suppressing Fe penetration into the bulk region of oxalates, resulting in a more uniform formation and widespread distribution of surface Fe sites. The optimized catalyst exhibits remarkable and stable catalytic performance, recording a current density of 200 mA cm-2 at an overpotential of 320 mV for 300 h.