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.

Automated summary

In this study, cobalt-based hydroxide derived from ZIF-67 was incorporated with iridium on the surface of Ni-contained carbon nanofibers to enhance its alkaline oxygen evolution reaction (OER) property. The optimized sample displayed remarkable OER activity, with an overpotential of only 240 mV to reach 10 mA cm-2, compared to commercial IrO2 electrocatalyst (331 mV). The unique nanofibrous structure of Ni-CNFs provided desirable electrical conductivity, leading to excellent durability for OER testing. Furthermore, a water electrolyzer built using the prepared Ni-CNFs/Ir-Co(OH)2 and Pt/C electrodes showed superior performance compared to Pt/C||IrO2 cell.