The oxygen evolution reaction (OER) is critical for hydrogen production in water splitting. Nickel-iron spinel-type oxides have been considered as one of the OER electrocatalysts, however, their low conductivity limits broader application. Herein, we synthesized the Ir (5% atomic basis) doped nickel-iron spinel oxide nanoparticles deposited on nickel foam (Ir-NFO/NF) to overcome the existing limitations. The cyclic voltammogram using the Ir-NFO/NF presents a low overpotential of 251 mV at the current density of 100 mA cm-2 for OER which outperforms the IrO2/NF and bare nickel ferrite (NFO)/NF. Furthermore, Ir-NFO/NF exhibits not only electrochemical activity but also extraordinary durability of maintenance of the potential without decay at 100 mA cm-2 for 130 days. The enhancement of active metal sites from the Ir doping effect was observed using in situ X-ray absorption spectroscopy. Under the OER regime, an increased oxidation state was noted primarily on Ni on NFO, whereas concurrent shifts were observed both for Ni and Fe on the Ir-NFO. The experimental results were supported by theoretical calculation based on density functional theory (DFT), to reveal that Ir facilitates the conductivity of the spinel oxide, extends active metals in the electrocatalyst, and promotes OER kinetics on active sites.

Dynamic extension of active sites formation in nickel-iron spinel oxide with iridium doping for oxygen evolution reaction

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.