Ni Foam-Supported Fe-Doped β-Ni(OH)₂ Nanosheets Show Ultralow Overpotential for Oxygen Evolution Reaction

Oxygen evolution reaction (OER) involves multiple electron-transfer processes, resulting in a high activation barrier. Developing catalysts with low overpotential and high intrinsic activity toward OER is critical but challenging. Here we report a major advancement in decreasing the overpotential for oxygen evolution reaction. Ni foam-supported Fe-doped β-Ni(OH) 2 nanosheets achieve an overpotential of 219 mV at the geometric current density of 10 mA cm -2 . To our knowledge, this is the best value reported for Ni- or Fe hydroxide-based OER catalysts. In addition, the catalyst yields a current density of 6.25 mA cm -2 at the overpotential of 300 mV when it is normalized to the electrochemical surface area of the catalyst. This intrinsic catalytic activity is also better than the values reported for most state-of-the-art OER catalysts at the same overpotential.