A methodology to recover the oxygen evolution reaction (OER) kinetics of aged, electrodeposited Fe-Ni-Co thin films is presented. The electrodeposits were fabricated galvanostatically onto rotating copper electrodes and contained a small amount of Co. The OER characterized in 1 M KOH was a function of the deposit composition. The Tafel slope and the overpotential at 10 mA/cm2 observed with ohmically corrected linear sweep voltammetry were both a function of the deposit metal ratio, Fe/(Ni + Co), with the lowest values occurring at a ratio of 1.2. An Fe-rich deposit was purposely altered upon aging to degrade the OER kinetics. The Tafel slope and overpotential were largely recovered when the aged electrocatalyst was treated with a cathodic current density of -100 mA/cm2 for 10 min. Soft X-ray absorption spectroscopy provided insight into the changes of the electron density distribution upon aging and regenerating the electrocatalyst. Through X-ray absorption near-edge structure (XANES), the L-edge spectra of Fe, Ni, Co, and K-edge spectra of O, suggested that the recovery is due to the redistribution of the electron density from the oxygen to Fe and Ni.
Publication Source (Journal or Book title)
ACS Applied Energy Materials
Zhang, Y., Kizilkaya, O., Bilan, H., Kurtz, R., & Podlaha, E. (2020). Activity and Regeneration of Electrodeposited Fe-Ni-Co-Based Electrocatalysts for the Alkaline Oxygen Evolution Reaction. ACS Applied Energy Materials, 3 (8), 7239-7245. https://doi.org/10.1021/acsaem.0c00985