Autologous growth of Fe-doped Ni(OH)2 nanosheets with low overpotential for oxygen evolution reaction

Abstract

Highly active and durable electrocatalysts for oxygen evolution reaction (OER) play a vital role in water splitting. Despite numerous efforts, the strategies to prepare durable and effective electrocatalysts via scalable methods still remain a great challenge. In this work, we fabricated Fe-doped Ni(OH)2 ultrathin nanosheets (Fe–Ni–OH/Ni) via autologous growing of Ni(OH)2 from Ni foam, and in situ electrochemical-assisted doping Fe into Ni(OH)2. Benefiting from the unique structure with large surface areas and strong coupling effects between Fe and Ni, the optimal Fe–Ni–OH electrodes exhibit remarkable catalytic performance toward OER, which requires an overpotential of 220 mV to achieve a current density of 10 mA cm−2 with a Tafel slope of 48.3 mV dec−1. The Fe–Ni–OH electrodes also possess high stability even under a high current density of 500 mA cm−2 for 600 h with an ultralow overpotential of 290 mV. Using Ni–Fe–OH electrodes as both anode and cathode for overall water splitting, only a small overpotential of 1.57 V is required to reach a current density of 10 mA cm−2. Moreover, the high catalytic performance and scalable preparation method can meet the emergency needs for the practical application.