In Situ Derived Ni_<i>x</i>Fe_1–<i>x</i>OOH/NiFe/Ni_<i>x</i>Fe_1–<i>x</i>OOH Nanotube Arrays\nfrom NiFe Alloys as Efficient Electrocatalysts for Oxygen Evolution

Abstract

Herein, Ni_<i>x</i>Fe_1–<i>x</i>OOH/NiFe/Ni_<i>x</i>Fe_1–<i>x</i>OOH\nsandwich-structured nanotube arrays (SNTAs) supported on carbon fiber\ncloth (CFC) (Ni_<i>x</i>Fe_1–<i>x</i>OOH/NiFe/Ni_<i>x</i>Fe_1–<i>x</i>OOH SNTAs–CFC) have been developed as flexible\nhigh-performance oxygen evolution reaction (OER) catalysts by a facile\nin situ electrochemical oxidation of NiFe metallic alloy nanotube\narrays during oxygen evolution process. Benefiting from the advantages\nof high conductivity, hollow nanotube array, and porous structure,\nNi_<i>x</i>Fe_1–<i>x</i>OOH/NiFe/Ni_<i>x</i>Fe_1–<i>x</i>OOH SNTAs–CFC exhibited a low overpotential of ∼220\nmV at the current density of 10 mA cm^–2 and a small\nTafel slope of 57 mV dec^–1 in alkaline solution,\nboth of which are smaller than those of most OER electrocatalysts.\nFurthermore, Ni_<i>x</i>Fe_1–<i>x</i>OOH/NiFe/Ni_<i>x</i>Fe_1–<i>x</i>OOH SNTAs–CFC exhibits excellent stability\nat 100 mA cm^–2 for more than 30 h. It is believed\nthat the present work can provide a valuable route for the design\nand synthesis of inexpensive and efficient OER electrocatalysts.