Amorphous\nNiFe Nanotube Arrays Bifunctional Electrocatalysts\nfor Efficient Electrochemical Overall Water Splitting

Abstract

It is still a challenge\nfor design and fabrication of cost-effective\nand efficient bifunctional electrocatalysts for both cathodic hydrogen\nevolution reaction (HER) and anodic oxygen evolution reaction (OER)\nfor overall water splitting. Herein, we design and synthesize amorphous\nNiFe nanotube arrays on nickel foam (NiFe NTAs-NF) with high electrocatalytic\nactivity and excellent durability for both OER and HER in overall\nwater splitting. The as-synthesized NiFe NTAs-NF only requires relatively\nlow overpotentials of 216 mV for the OER and 181 mV for the HER to\nreach current densities of 50 and 10 mA cm^–2, respectively.\nMoreover, when used as bifunctional catalysts for water splitting,\nthe designed electrode only needs a low cell voltage of 1.62 V to\nobtain 10 mA cm^–2 for the overall water splitting,\nwith an extremely excellent durability. The excellent performance\nof the NiFe NTAs-NF might be attributed to the synergistic effect\nand amorphous phase of NiFe alloy as well as the well-defined nanotube\narray architecture with large surface area, abundant active sites,\nand sufficient gas and electrolyte diffusion channels.