LAUSR

Abstract An efficient, cost-effective, and more readily available electrocatalysts that can lower the overpotential associated with oxygen evolution reaction (OER) is a prerequisite for the application of water splitting for hydrogen production at a larger scale. Herein, we demonstrate a composite electrode obtained by anchoring polyhedral Fe3O4 particles on nickel foam (NF) is a highly active catalyst for OER. Notably, this catalyst was able to achieve a current density of 10 mA cm−2 and 100 mA cm−2 at a low overpotential of 251 and 310 mV. Also, Fe3O4-NF displayed a low Tafel slope of 45 mV dec−1. Moreover, at an overpotential of 300 mV Fe3O4-NF showed a turnover frequency (TOF) of 3.12 × 10−3 s−1 suggesting that Fe3O4-NF has a high intrinsic catalytic activity which is on par with commercial RuO2 catalyst. Furthermore, due to the close contact and strong adhesion between Fe3O4 and NF, the Fe3O4-NF displayed good stability during OER. The post-activity characterizations indicate that iron oxyhydroxide (Fe(O)OH) formed due to in-situ oxidation of Fe3O4 surface functions as the active catalytic phase whereas, bulk of the catalyst acts as a conducting scaffold.