Iridium incorporated cobalt-based hydroxide on nickel-contained carbon nanofibers renders highly efficient oxygen evolution reaction

The construction of high-performance oxygen evolution reaction (OER) electrocatalysts is crucial for energy applications. Here, we demonstrate a reliable route to incorporate iridium (Ir) into cobalt (Co)-based hydroxide derived from ZIF-67 on the surface of Ni-contained carbon nanofibers (denoted as Ni-CNFs/Ir-Co(OH)2) as an electrocatalyst to boost its alkaline OER property. The optimized Ni-CNFs/Ir-Co(OH)2 sample exhibits an extraordinary OER activity with an overpotential of only 240 mV to reach 10 mA cm-2, much lower than that of commercial IrO2 electrocatalyst (331 mV). The theoretical results illustrate the highly active Co sites of Iredge-Co (OH)2 for OER. Furthermore, the distinct nanofibrous architecture of Ni-CNFs endows with a desirable electrical conductivity of the catalyst, thus the Ni-CNFs/Ir-Co(OH)2 sample presents a desirable durability for OER testing. In addition, a total water electrolyzer is built by using the prepared Ni-CNFs/Ir-Co(OH)2 and Pt/C as electrodes, which requires only 1.50 V at 10 mA cm-2, superior to the value of Pt/C||IrO2 cell (1.62 V). This study puts forward an effective route to explore superior OER electrocatalysts by engineering the electronic structure of metal hydroxide for energy applications.