Facile Preparation of Amorphous Fe-Co-Ni Hydroxide Arrays: A Highly Efficient Integrated Electrode for Water Oxidation.

Facile and fast synthesis of functional materials with high catalytic activity is highly demanded to meet the industrial production and applications such as electrolysis. In this study, Ni foam is employed as the current collector and Ni source, which is dipped into the mixture of Fe and Co metal ions solution at room temperature for several minutes, to in situ grow Fe-Co-Ni hydroxide arrays and construct the three-dimensional integrated electrode. This short-time preparation at room temperature is beneficial to avoid the rapid growth of the generated primary nanocrystallites and cause intimate interactions between Fe, Co, and Ni atoms. The obtained self-supported and vertically aligned Fe-Co-Ni hydroxides present an amorphous phase, which exhibit high activity with low overpotentials of 212 mV at 10 mA cm-2 and 319 mV at 100 mA cm-2, associated with a small Tafel slope of 52 mV dec-1 toward the oxygen evolution reaction.